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Fishing and Benthic Habitats 2002: Abstracts

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ABSTRACTS
(alphabetical by first author)
See the original Abstracts document here

ALLEN, Y. (allenyc@lsu.edu)*, C. WILSON, H. ROBERTS, AND J. SUPAN; Oyster Geophysics Program, Department of Oceanography and Coastal Sciences, SC&E, Louisiana State University, Baton Rouge, LA. Using sidescan sonar to assess the impact and persistence of natural and anthropogenic disturbance to low-relief oyster habitats in coastal Louisiana.

Traditional methods used to assess oyster reef distribution and condition are only able to provide subjective point information, which is often poorly georeferenced.  Maps of oyster habitat in shallow waters are therefore typically extremely generalized, giving few details about the true distribution, character and dynamics of reefs.  Sidescan sonar offers a significant advantage for oyster reef assessment in the turbid waters of coastal Louisiana.  We used sidescan sonar in ultra-shallow (<2m) waters to completely image over 19,000 ha in Louisiana estuaries in advance of an impending freshwater diversion project.  We also conducted four years of intense annual surveys in a more restricted area (320 ha) with a diversity of reef types and culture intensity to examine natural and anthropogenic impacts on oyster reef extent and character.  Our intensive surveys identified older stable reefs that had not been actively worked.  Shell abundance and structure on these reefs were high, but oyster meat productivity was low.  Areas of intense oyster culture were characterized by low relief reefs that frequently showed distinct evidence of scarring from dredging and other anthropogenic sources.  Smaller scars caused by oyster dredging typically healed through the within time period of our study while larger anthropogenic scarring did not diminish over the four years.  We also deployed the sonar towfish over an area immediately before and after both seeding and harvesting to establish a quantitative relationship with sonar reflectance.  These relationships can be further used to predict the impact of harvesting and seeding on the extent oyster habitat.

ALEXANDER, C. (clark@skio.peachnet.edu)*¹, G. MCFALL², T. BATTISTA³, AND R. BOHNE²;  ¹Skidaway Institute of Oceanography, Savannah, GA, ²Grays Reef National Marine Sanctuary, Savannah, GA, ³National Ocean Service, Silver Spring, MD. Benthic habitat characterization of the Grays Reef National Marine Sanctuary using sidescan, multibeam and GIS techniques.

NOAA's Grays Reef National Marine Sanctuary has been completely mapped by the NOAA ship Whiting using multibeam and sidescan sonar techniques.  The resulting data mosaics portray the geologic controls on the character of reef habitat as well as the signatures of modern processes affecting the reef.  The multibeam data differentiate between the rocky and sandy habitats and illustrate the influence of pre-existing geologic structure on the general morphology of the reef.  Sidescan data highlight the fine-scale detail of the rugged reef surface, the influence of bioerosion on the reef surface and the dynamics of mobile, unconsolidated sediments, which periodically alter reef benthic habitats by covering and exposing rocky substrate.  GIS techniques, coupled with the high-resolution sidescan data, are being employed to automatically resolve and classify benthic habitats.  Diver observations of fish distributions will be compared to benthic habitat distribution determined from the sidescan and multibeam datasets.

ALMEIDA, F. (frank.almeida@noaa.gov)*¹, P. VALENTINE⁴, R. REID², L. ARLEN², P. AUSTER³, J. CROSS², V. GUIDA², J. LINDHOLM³, J. LINK¹, D. PACKER², J. VITALIANO², and A. PAULSON²;  ¹National Marine Fisheries Service, Northeast Fisheries Science Center, Woods Hole, MA, ²National Marine Fisheries Service, Northeast Fisheries Science Center, Highlands, NJ, ³NOAA, National Underwater Research Program, University of Connecticut, Groton, CT, ⁴U.S. Geological Survey, Woods Hole Field Center, Woods Hole, MA. The effectiveness of marine protected areas on fish and benthic fauna: the Georges Bank closed area II example.

In late 1994, a substantial portion of eastern Georges Bank was closed to commercial fishing (Closed Area II) to assist with stock rebuilding.  After about five years of closure, the southern portion of CAII (south of 41°30'), exhibited a substantial increase in biomass and density of sea scallops, Placopecten magellanicus, and was reopened to the scallop fishery.  Before the industry was allowed entry into this area, we conducted a survey to monitor the recovery of benthic habitat and fauna inside CAII.  Sampling sites were selected in a paired station design for an inside/outside comparison; a grid design was used to monitor the remainder of the inside area.  At each station, we conducted video transects, collected still photos, CTD casts, and sediment samples for physical and chemical analysis.  A Smith-McIntyre bottom sampler was then used to sample the benthic community, followed by an otter trawl.  Trawl catches were sorted to species and all fish and invertebrates were weighed, enumerated, and measured.  Stomach contents, maturity observations, and age structures were collected for selected species at each station.  Our results suggest limited differences between the inside/outside paired stations for species composition, community diversity, species richness, and trophic ecology.  Fish abundance and biomass was also similar inside and outside the area; however, most individuals of a species were larger inside than outside.  The lack of other major differences is likely a result of the fact that the seabed in the southern portion of CAII is a relatively high-energy sand habitat of low to moderate complexity and has a relatively low vulnerability to trawling and dredging.  Other parts of closed areas on the northeast shelf may exhibit stronger gradients for the same metrics due to the presence of higher complexity gravel habitats and increased vulnerability to bottom tending fishing gear.  The subtle differences in the size structure of fish species we observed in CAII may have significant implications for the population dynamics of commercially valuable species.

ANDERSON, JOHN T. (andersonjt@dfo-mpo.gc.ca); Northwest Atlantic Fisheries Centre, Department of Fisheries and Oceans, St. John's, Newfoundland, Canada. Linking fisheries to benthic habitats requires observations at multiple scales.

Management of commercial fisheries typically occurs at the scale of fishing banks for annual periods. Spatial structure within management areas is usually ignored. Historically, fisheries observations have been at the scale of individual bottom trawl tows allocated randomly within strata. Analyses of these data can reveal spatial structures within bank-scale management units that are consistent over many years. We interpret spatial stationarity as an indication of preferred habitats. In Atlantic cod (Gadus morhua), we have found that spatial structure is size dependent, where small juveniles occupied different areas than larger conspecifics. Within these large areas of occurrence we ask: how are juvenile cod distributed? Recent research on juvenile cod has revealed spatial structure can be on the order of meters. However, relating observations at small scales to larger areas remains a central problem facing fisheries ecologists. Scaling-up requires definition of the spatial and temporal heterogeneity of the fine-scale information and, secondly, correctly integrating this heterogeneity to the larger scale. Integration requires information on the spatial distributions of fish and their habitat associations from meters to kilometres. Current technologies exist to carry out such observations. Our recent research has combined acoustic and optical observational systems that are capable of measuring fish and habitat distributions from meters to kilometres in scale. Such combined observational systems should provide the descriptive basis towards defining spatial heterogeneity and modeling this heterogeneity at larger scales.

ANDERSON, T.J.(tara.anderson@noaa.gov); NOAA National Marine Fisheries Service. Santa Cruz Laboratory, Santa Cruz, CA, and U.S. Geological Survey, Coastal and Marine Geology, Menlo Park, CA. Understanding the complex nature of fish-seagrass associations.

Seagrass beds are rarely homogenous entities. Instead, they form a mosaic that is structured at many different scales. This has important implications for fish communities. However, while seagrass beds are known to have higher abundances of fishes and greater richness of species than unvegetated habitats, few studies have identified how fish dispersions are modified by the spatial structure inherent in most habitats.  In this study a multi-scaled observational (meters to 30 km) and experimental approach was used to quantify the relationship between demersal fishes and subtidal seagrass areas in Port Phillip Bay, Melbourne, Australia.  While most species were correlated with seagrass, either directly (e.g. seagrass density and length) or indirectly (e.g. patchiness), seagrass alone did not explain species distributions.  Instead, the association of a fish with it's 'preferred' habitat was conditional on the spatial structure of the habitat and the spatial location along the shore, and that these landscape elements operated additively, or synergistically.  Additionally, a large-scale temporal dynamic both in the supply of larvae and in seagrass health and presence also operated across all scales examined. This study highlights that measuring the association between organisms and their habitat requires many levels of information, ranging from understanding individual habitat preferences at fine-scales, to understanding the spatially-explicit structure of fish and habitat at landscapes.  Understanding and predicting fish assemblage structure in the face of habitat change is no simple task, and relies heavily on the integration of fine-scale empirical and landscape-level studies, but this study demonstrates it is achievable.

ANDERSON, T.J. (tara.anderson@noaa.gov)*^1,2, M.M. YOKLAVICH¹, S. EITTREIM², R. STARR³, L. SNOOK⁴; NOAA National Marine Fisheries Service. Santa Cruz Laboratory, Santa Cruz, CA, ² U.S. Geological Survey, Coastal and Marine Geology, Menlo Park, CA, ³California Sea Grant Extension Program, Moss Landing, CA, ⁴Moss Landing Marine Laboratory, Moss Landing, CA. Fine-scale distribution of groundfish populations: does habitat configuration and patchiness matter?

At a local scale, mobile organisms can exert considerable choice about their occupancy of microhabitats. Fine scale habitat structure and patchiness can modify the local distribution of fishes, and hence alter the strength of interactions with each other and their environment. In this study we evaluated the association of groundfishes with fine scale habitat composition and structure. We integrated in situ fish counts and habitat measures collected from the Delta submersible during September 1994 with multibeam sonar data to explore how fine scale habitat associations can be scaled to the larger landscape. This initial study highlights both the importance of measuring fish-habitat associations at multiple scales and the implications for 'scaling up' groundfish abundances from fine scale transects to landscapes derived from broader scale habitat maps.

ARCHAMBAULT, P. (archambaultp@dfo-mpo.gc.ca)* and L. GENDRON; Department of Fisheries and Oceans Canada, Institut Maurice-Lamontagne, Mont-Joli, Québec, Canada. The impact of scallop dredging on the American lobster (Homarus americanus) in the Baie des Chaleurs, Canada.

Lobster fishers in eastern Canada often complain that scallop dredging is responsible for local declines in lobster landings of the American lobster through destruction of lobster habitat. In Baie des Chaleurs, although scallop dredging is restricted to depths over 18 m to 27 m, depending on the season, it nevertheless occurs in areas where lobster is known to be present at certain times of the year. The aim of this project was to determine to what extent scallop fishery spatially overlaps lobster grounds and to examine the impact of scallop dredging on lobster habitat, more specifically in terms of loss of bottom complexity. Such a loss could affect the survival of lobster at different stages of its life, especially cryptic juvenile stages. The study was concentrated in two localities, for which fisheries managers have received site-specific request to assess the link between these two fisheries. Seasonal adult lobster distribution was examined from lobster fishing activity and from off-season experimental fishing. Location of dredging activities was obtained from scallop fishers logbooks. Habitat, in overlapping areas, was characterized using an acoustic device. Furthermore, abundance of juvenile and adult lobsters was evaluated along transects running across the overlapping area. Additionally, experimental dredging was performed at one depth and a 'Before-After-Control-Impact design' was used to identify the immediate impact of the scallop dredge on habitat complexity and benthic community. Results will be discussed in relation to the possible mechanisms explaining how lobster landings could be affected by scallop dredging activity.

ARREGUIN-SANCHEZ, F. (farregui@ipn.mx); Centro Interdisciplinario de Ciencias Marinas del IPN, La Paz, Baja California Sur, México. Scientific advice to manage benthic fisheries in Mexico: present status and perspectives.

As in many countries, the tradition of scientific guidance for fisheries management in Mexico has been based on the population dynamics of the target stocks. Most work developed for management responds to the need to protect fisheries from intensive exploitation; and in general terms, it is aimed at avoiding recruitment or growth over-fishing. For this, different strategies have been implemented: closures in time and space, minimum legal sizes, number of licenses, catch quota, control of fishing effort, proportional escapement, and others. The type of measure applied depends on the specific life strategy and problem. Complexity of analytical tools also varies according to the degree of knowledge required, from a general and simple population dynamics study to a formal and complex simulation experiment including risk and uncertainty analysis. Other management initiatives requiring scientific advice are aimed at conservation of some stocks involving closures, use of excluders, as well as natural reserves and protected areas closed to exploitation. Management is frequently conducted by federal and local governments, but in some few cases co-management has been put in practice. Mexico recognizes the importance of precautionary management principles emerging from international forums, and a strong effort is being developed in this way. Recently an ecosystem-based approach has alternatively supported management schemes, but even when more information is clearly offered, the main problem is that ecosystem-based management requires participation of all ecosystem users (i.e all fleets) which in some cases results in negative benefits for some of them in order to improve ecosystem health, global yields or stocks recovery. An ecosystem approach is also being used to evaluate the impact of fishing on the dynamics and structure of ecosystems, in which a strong effort is being developed. This scientific work is aimed at supporting ecosystem health, conservation and sustainable exploitation as common criteria. All the above situations are illustrated with fisheries from all the littorals of Mexico.

BAIRD, S.J. (s.baird@niwa.cri.nz)*, N.W. BAGLEY, B.A. WOOD, A. DUNN, and M.P. BEENTJES. National Institute of Water and Atmospheric Research, Kilbirnie, Wellington, New Zealand. The spatial extent and nature of mobile bottom fishing methods within the New Zealand EEZ, 1989-90 to 1998-99.

Temporal-spatial representation of fishing effort distribution for the main mobile bottom fishing methods used in New Zealand waters was investigated using 10 years of commercial effort data, from 1989-90 to 1998-99. Tow position data were used to map the changes in fishing patterns for fisheries using otter trawls on the bottom by collating the number of fishing operations and the area swept into 22 km2 blocks. The intensity of effort varied between fishing years: many 22 km2 blocks were trawled more than 10 times, representing a swept area of more than 10 km2. In most fishing years a median of 2 tows were made in each block (with the third quartile at 4-6 tows) and the maximum number of tows in a block was 370. Swept area values were scaled to vessel power and graphic representations of these data indicated areas trawled by heavier ground gear. Transects of selected areas for each fishing year showed large differences in the monthly spread of effort. Analyses of data for other otter trawl effort (predominantly inshore) and shellfish dredge effort are based on larger fishery areas because fine-scale position data were not collected. At this scale, spatial and temporal relationships between fisheries with different gear types were evident. Ground gear components used in the main otter trawl and dredge fisheries are described. The requirements for consistent data collection and the application of this work to a wider understanding of the impact of fishing in New Zealand waters are discussed.

BARNES, P.W. (pbarnes@usgs.gov)*, G.W. FLEISCHER, J.V. GARDNER, and K.M. LEE; U.S. Geological Survey, Menlo Park, CA.  Using laser technology to characterize substrate morphology of lake trout spawning habitat in Northern Lake Michigan.

As part of a strategy to re-establish devastated native lake trout stocks, six areas of offshore and coastal Lake Michigan habitat were mapped with SHOALS bathymetric lidar in late summer 2001 in cooperation with the U.S. Army Corps of Engineers.  Decimeter elevation/bathymetric data referenced to IGLD85 datum were obtained on a 4 m grid over a total area of about 200 km2 in water depths from 0 to 30 m.  Shaded relief and color-coded depth images were developed within coarser regional gridded bathymetry and subaerial DEM as a basis for maps and initial interpretation.  Sparse substrate samples, underwater diver and useful but local video observations supplement the morphologic information.  Three geologic regimes are present in the area and form the basis for substrate, habitat and morphologic classification.  Devonian and Silurian carbonates underlie the region.  Morphologic scarps and bedding(?) lineations suggest bedrock at or near the surface at all of the mapped areas, but confirmation is lacking.  Overlying bedrock are glacial deposits including compacted clay tills and outwash gravel and sand.  The orphology and video observations suggest NW-SE basal till lineations and small (1-3km) cobble and boulder moraines with outwash deposits. Post-glacial reworking appears minimal in depths greater than 10m. Modern sand deposits appear as thin down-drift (to the east) bedforms, sand sheets and depositional lobes, except along the coast of Little Traverse Bay where well developed, en-echelon nearshore bars are present at the head of the bay.   Laser waveform data is being analyzed for benthic albedo information and biologic data is being incorporated with the morphologic and geologic observations toward classifying and mapping preferred lake trout spawning habitat.

BEAULIEU, S.E. (stace@whoi.edu)*¹, H. SINGH¹, and K.L. SMITH JR.²;  ¹Applied Ocean Physics and Engineering Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, ²Marine Biology Research Division, Scripps Institution of Oceanography, La Jolla, CA. Analyzing time-lapse photographs of the sea floor for changes in benthic community activity.

Time-lapse photographs or repeated photographic surveys of the sea floor can be used to study the response of benthic fauna to a natural or anthropogenic disturbance.  We are interested in the responses of epibenthic megafauna to a temporally varying food supply, or flux of particulate matter to the sea floor.  At a deep-sea study site, we have amassed ~10 years of time-lapse photographs, taken once per hour, of ~20 m² of the sea floor.  We would like to analyze this 10-yr time series for seasonal changes as well as long-term trends in the benthic community.  In addition to species composition, abundance, size, and activity of megafauna (with an activity index based on area traversed per unit time), we would like to trace sediment features such as mounds and tracks.  Because manual analysis of the large number of photographs is very labor-intensive, we developed image-processing routines that make it easier to analyze oblique photographs, such as detecting organisms and their tracks.  Our methods include: 1) digitizing the film, 2) adjusting light on the images (histogram equalization), 3) converting oblique photographs to plan view, and 4) automated image processing, with routines based on edge detectors and morphological operators.  We will present results for a 4-mo time series at the deep-sea site, with natural disturbance from a massive accumulation of phytodetritus on the sea floor.  We plan to use these algorithms for photographs taken in other soft-bottom habitats, including images transmitted in real-time from the Hawaii-2 Observatory in the abyssal Pacific.

BENTLEY, S. J. (sjb@lsu.edu)*¹, W.F. PATTERSON², Y. ALLEN³, W. VIENNE¹, and C. WILSON³;  ¹Department of Oceanography and Coastal Sciences and Coastal Studies Institute, Louisiana State University, Baton Rouge, LA, ²Dauphin Island Sea Lab, Dauphin Island, AL, ³Department of Oceanography and Coastal Sciences and Coastal Fisheries Institute, Louisiana State University, Baton Rouge, LA .  Geoacoustic and geological characterization of juvenile red snapper habitat; Northern Gulf of Mexico continental shelf.

Laboratory and small-scale in situ experiments have demonstrated juvenile red snapper display an affinity for low-relief shell-rubble habitat; however, the spatial extent and temporal variability of large-scale shell-rubble features on the Mississippi-Alabama shelf are unknown. Moreover, the seabed geology of the entire region in general is poorly known, with little significant research conducted since the 1950's. Therefore, to develop a geological understanding of quality juvenile snapper habitat in the region, we have undertaken a program of sidescan seabed mapping and seabed sampling in areas on the northern Gulf of Mexico continental shelf that historically produced high, median, and low juvenile red snapper catch rates in trawl surveys. Preliminary results of sidescan surveys and grab samples indicate highest juvenile snapper catch rates are found near irregular low-relief ridges of shell and sand, with CaCO₃ content to 100%. The ridges are elevated 1-2 m above the surrounding seabed and generally orient along NW-SE axes. Surrounding seabed is more typical of the Holocene transgressive sand sheet, composed of fine-medium muddy sand with shell content <10%. Most shell material found on the ridges appears to be fragments of the oyster Crassostrea (now highly encrusted by epibionts), indicating ridges are of estuarine origin, and are probably remnants of coastal shell reefs formed during the Holocene Transgression (i.e., during the past ~6000 y). Ongoing research focuses on elucidating origin of the ridges, developing a geoacoustic fingerprint for quality juvenile red snapper habitat, and examining temporal and spatial variability in juvenile snapper habitat utilization patterns.

Bergmann, M. (m.bergmann@bangor.ac.uk)*¹, H. Hinz¹ M.J. KAISER¹, and S.I. Rogers²;  ¹School of Ocean Sciences, University of Wales-Bangor, Wales, United Kingdom, ²CEFAS Lowestoft Laboratory, Lowestoft, Suffolk, United Kingdom. Assessing dietary specialism and food niche breadth of cod and whiting to identify possible 'essential fish habitats' in the Irish Sea, UK.

Demersal fish assemblages are intimately associated with benthic habitats where they spend a large part of their time feeding and avoiding predators.  Bottom fishing activities can degrade seabed habitats and change benthic communities by reducing their complexity.  Thereby they can also degrade essential fish habitats such that they can no longer sustain the fish species associated with them.  Having established a relationship between cod (Gadus morhua) and whiting (Merlangius merlangus) and specific Irish Sea habitats from consultation with fishers and ground fish surveys we wanted to learn what functional role these habitats play, i.e. as sources of prey and shelter from predators.  Habitats complexity of stations with high and medium fish densities was assessed using side scan sonar, QTC View^TM and underwater photography.  Young cod were particularly abundant in a habitat with mixed sediments (low grain size sediments between stones and shells) and emergent epifauna off Belfast Lough (Northern Ireland).  Dietary specialism indicates a close association with a particular habitat, while broader diets within and between different areas indicate a weaker association of a fish species with a particular habitat.  The availability of prey organisms was assessed by sampling epifaunal and infaunal organisms with a 2-m beam trawl and a Day grab.  Demersal fish for condition and stomach contents analysis were collected by otter and beam-trawling.  The results from stomach content analysis of cod and whiting are discussed in relation to the prey availability found in the study areas and food niche breadth.

BIZARRO, J.J.¹, J.M. FIELD (JField@ci.pacific-grove.ca.us)*¹, H. G. GREENE¹, R.N. LEA², and J. deMARIGNAC¹;  ¹Center For Habitat Studies, Moss Landing Marine Laboratories, Moss Landing, CA, ²California Department. of Fish and Game, Monterey, CA.  Habitat associations of upper slope rockfishes (Sebastes spp.) and co-occurring demersal fishes in Ascension Canyon, California.

Due to their typical life history patterns (slow growth, late age at maturity, extreme longevity) deep-water rockfishes (Sebastes spp.) are especially susceptible to overfishing, as evidenced by recent declines in most commercially targeted stocks.  To establish effective Marine Protected Areas (MPAs), the interaction between fishes and their available habitats must be determined.  Our objectives were to describe habitat associations for upper slope rockfishes and co-occurring fish species within the headward part of Ascension Canyon at both large (1 to 10s of kilometers) and small (10s to 100s of meters) scales. Geologic structure and lithology were investigated using high-resolution multibeam bathymetric and backscatter data.  These data were interpreted to produce habitat maps of the study area.  Seafloor features and fish assemblages were then surveyed using the Delta submersible at 50-meter intervals between 200 and 350 m.  Thirty-two ten minute transects were completed between two distinct, large-scale habitat types.  At 200 and 250 m, stripetail (Sebastes saxicola} and greenstriped (S. elongatus) rockfishes were the dominant fish species.  At 300 and 350 meters, splitnose (S. diploproa) and shortspine thornyhead (Sebastolobus alascanus) were the most abundant rockfishes.  Large and small-scale habitat associations of these and several other commercially important demersal fishes were also determined.

BLOESER, J. (Jennifer@pmcc.org); Pacific Marine Conservation Council, Arcata, CA. Development of a West Coast cooperative research program, working together towards better information.

The Pacific Marine Conservation Council (PMCC) is presently working with federal and state agencies, scientists and fishermen to develop a West Coast Groundfish Cooperative Research Program. This program will provide a clearinghouse for ongoing cooperative research projects. It will also house the primary source of information on research priorities, funding and contacts for interested scientists and fishermen.  The need for systematically combining the expertise of fishermen with the scientific rigor of researchers has clearly emerged in the evolution of our Rockfish Rebuilding Campaign, launched in 2001.  Cooperative research programs provide a unique opportunity for those interested in fisheries to collectively resolve complex issues. Through collaboration, federal agencies and fisheries managers benefit from the experience, equipment, and insights of fishermen, while fishermen participate in designing and conducting the research to gather data for superior management of the resource. PMCC strongly believes that sustainable fisheries depend upon implementing standardized methods of collecting, analyzing and applying the 'experiential' data of fishermen to fisheries science. Cooperative research also has the potential to improve communication and trust while elevating the level of scientific understanding.

BLYTH, R. E. (osp818@bangor.ac.uk)*¹, M.J. KAISER¹, G. EDWARDS-JONES² and P.J.B. HART³;  ¹School of Ocean Sciences, University of Wales-Bangor, Anglesey, United Kingdom, ²School of Agricultural and Forest Sciences, University of Wales-Bangor, Bangor, Gwynedd, United Kingdom, ³Department of Biology, University of Leicester, Leicester, United Kingdom.  Biological and socio-economic implications of a limited access fishery management system.

Marine reserves are considered to be effective conservation tools in tropical waters, but to date few studies have determined the economic and biological implications of limited access fishery management systems in temperate zones. The Inshore Potting Agreement (IPA), a fishery management system operated off the south coast of the United Kingdom, was conceived to reduce conflict between fishers that operate towed bottom-fishing gears and fishers that operate static gears. This system has operated on a voluntary basis since 1978, and covers an area of 480km². In this study, an interview survey of fishers, associated industry members and interested parties determined the economic implications of the IPA. Long-term recreational angling records from within and outside the area of the IPA were analysed to determine possible biological benefits for large-bodied fishes. The results suggest that the long-term maintenance of the IPA is likely to have greater economic and social benefits for local communities than if the area was open to all fishing activities.

BRANCATO, M.S. (mary.sue.brancato@noaa.gov)* and C.E. BOWLBY; Olympic Coast National Marine Sanctuary, Port Angeles, WA.  Survey of fishing gear and fiber optics cable impacts to benthic habitats in the Olympic Coast National Marine Sanctuary.

In September 2000 the Olympic Coast National Marine Sanctuary (Sanctuary) initiated a long-term monitoring program designed to assess impacts to the seafloor and the benthic communities from different intensities of commercial bottom trawling and the placement of two fiber optics cables on the seafloor in the Sanctuary.  Survey sites were selected based on side scan and bathymetry data and bottom trawling records from Washington Department of Fish and Wildlife, Oregon Department of Fish and Wildlife, National Marine Fisheries Service and vessel traffic tracking information collected by the Sanctuary.  We conducted our first two years of monitoring using the Delta submersible equipped with underwater cameras, box core and a benthic suction device (slurp gun). In addition, a shipboard bottom grab was used to collect bottom samples.  Four distinct habitat types were monitored along low and high intensities of bottom trawling both along the buried cable route and parallel to the route.  The underwater surveys were conducted at depths of 120 to 330 meters along silt/clay, sand, gravel/cobble or boulder with mixed sediments.  Physical, chemical, and biological parameters were monitored.

BREMNER, J. (julie.bremner@ncl.ac.uk)*¹, C.L.J. FRID¹, and S.I. ROGERS²;  ¹Department of Marine Sciences and Coastal Management, Dove Marine Laboratory, University of Newcastle upon Tyne, Tyne and Wear, England, ²Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory, Lowestoft, Suffolk, England.  Biological traits of the North Sea benthos - does fishing affect benthic ecosystem function?

Assessments of species composition provide valuable information about the effects of anthropogenic activities. However, we must learn more about how ecosystems function and why changes occur in order to fully understand the implications of our activities and how to manage them appropriately. Recent interest in the factors structuring biotic communities has led to the use of variables such as feeding groups and size-spectra in benthic assessments. These have allowed progress in the examination of systems' functional makeup but only address part of the picture in terms of how ecosystems work. Biological traits analysis aims to investigate the attributes of species within a community in order to get a picture of how systems function as a whole. This approach incorporates information on the interactions both between species and between species and their environment. It includes information on feeding interactions, size, life history, habitat requirements and morphology as well as retaining information on species distributions. It is hoped that ultimately the approach will reveal the major rules structuring benthic ecosystems and highlight the degree of perturbation they can tolerate before this underlying structure breaks down. This poster describes the application of biological traits analysis to the benthic fauna of the North Sea benthos. The region has been heavily trawled for centuries and changes in species composition have been linked to fishing. This study investigates the functional structure of the ecosystem and how the traits present have responded to fishing disturbance.

BROTHERS, G. (brothersg@dfo-mpo.gc.ca)*¹ and J.J FOSTER²;  ¹Fisheries and Oceans Canada, Fisheries Management Branch, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland, Canada, ²Aquaprojects Inc., St. John's, Newfoundland, Canada.  Effect of shrimp trawling on snow crab resource in the northwest Atlantic.

The decline of the Northern Atlantic Cod stock and favorable environmental factors have led to an increase in the Northern Pink Shrimp (Pandalus borealis) Total Allowable Catch from 37,000 MT in 1996 to 112,000 in 2002.  As well, an additional 365 new, <20 meter vessels have been added to the existing fleet of 13, >50 meter vessels involved in harvesting the resource.  Shrimp and Snow Crab (Chionoecetes opeilio) are known to cohabit the same area, and as such, many crab fishers have expressed concern that shrimp trawling may be having a negative impact on the crab resource.  In 2001, a two-phase study was begun to determine the interaction between shrimp trawling and the crab resource.   Phase one of the study was conducted in a small area (0.5 x 4 miles) cohabited by crab and shrimp. The experimental design called for three fishing trips to be undertaken, the first directing for snow crab, the second directing for shrimp, and the third directing for crab. Crabs sampled were examined to determine 'new' and 'old' leg losses and then released 10 miles from the study area.  Phase two of the study which was undertaken in 2002, consisted of three, five-day shrimp trawling trips carried out in an area 5 x 10 miles where shrimp and crab cohabit. The shrimp trawl had three retainer bags attached underneath the trawl and behind the footrope to capture the crab that passed over and under the trawl footrope.  12,000 crab captured in the retainer bags were examined for 'new' and 'old' leg losses and then released 10-miles from the study area.  Analysis of  'old' and 'new' leg losses were compared before and after trawling (phase I) and after trawling and at various times of the year (phase II), and phase one and two data were also compared.  Results presented (with confidence limits) that cover both phases indicate a low percentage of recent leg loss, suggesting that shrimp trawling did not adversely impact crab encountered during the two-phase study.

BROTHERS, G. (Brothersg@dfo-mpo.gc.ca); Fisheries and Oceans Canada, Fisheries Management Branch, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland, Canada. Promoting environmental awareness and developing conservation harvesting technology for the fishing industry.

The Fisheries Diversification Program, a Canada / Newfoundland Cooperation Agreement, has four components. One of which deals with Environmental Awareness and Conservation Technology. During the past two years several projects have been carried out jointly with the fishing industry.  They include; Awareness of Gillnet Environmental Impact, Cod by-catch in American Plaice Gillnets, Impact of Scallop Fishing on Lobster Habitat workshop, By-Catch of Juvenile Groundfish and Pelagic in Shrimp Trawls, American Plaice By-Catch on Cod Longlines, Size Selectivity in Yellowtail Bottom Trawls, effect of Chaffing Gear on Codend Selectivity, and Crab by-catches in Scottish Seines. The methodology used and results obtained in each of these projects will be depicted in a poster session.  Results obtained during some of the projects have produced changes in the way commercial fishing is carried out and managed.

BROWN , E. (ftejb@uaf.edu)*¹, B. FINNEY¹, S. HILLS¹, and M. DOMMISSE²;  ¹Institute of Marine Science, University of Alaska Fairbanks, Fairbanks, AK, ²Monash University, Department of Geography and Environmental Science, Clayton, Australia. Impacts of commercial bottom trawling on the sediment characteristics and benthic community of essential fish habitat on the inner Bering Sea shelf.

Evaluation of impacts to essential fish habitat by commercial bottom trawling is needed to ensure long-term sustainability of the ecosystems that support these fisheries. Changes in sediment properties and benthic community composition resulting from bottom trawling were determined, and compared to natural disturbance in a shallow, sandy habitat in the Bering Sea. Our site is in the Nearshore Bristol Bay Closure, where trawling is prohibited except for one commercial flatfish fishery, and spans this fishery area and the Walrus Islands State Sanctuary, which serves as a control. Acoustic data, cores, grabs and video were randomly collected in the closed and fished areas, and immediately pre and post experimental trawling. Wave and tide data from NDBC buoy 46035 were used to estimate near bottom current speeds and the frequency and magnitude of sediment resuspension events. Significant changes in the sediment grain size distribution and chlorophyll a content indicate shifts in the fine fraction to 2-3cm depth. Such changes may result from redistribution by turbulence following the net, which differs in timing and magnitude from naturally occurring wave-driven bottom currents. The implications of these changes in the sediment structure are evaluated relative to shifts in benthic communities. Of the epifauna, only the abundance of the dominant seastar, A. amurensis is significantly reduced after experimental trawling. This could be the result of direct removal as was documented during fishing. Alternatively, a shift from a more dispersed distribution pattern to dense feeding clusters associated with processing waste may have biased our video analysis. Infauna analyses are in progress.

BROWN, J.K. (Jeff.K.Brown@noaa.gov)*, D.W. PRITCHARD, and G.T. NOLL; NOAA National Ocean Service, Office of Coast Survey, Hydrographic Systems and Technology Programs, Silver Spring, MD.  Distribution of acoustic backscatter imagery from NOAA hydrographic surveys.

Congress appropriated $6.2 million in Fiscal Year 2002 spending for NOAA to upgrade its hydrographic surveying equipment on board the four NOAA survey vessels operating in support of safe navigation.  This is NOAA's first fleet-wide hydrographic equipment purchase since 1992.  The NOAA Office of Marine and Aviation Operations, together with the National Ocean Service's Office of Coast Survey, specified and procured five Klein 5500 high-speed high-resolution side scan sonarsÑone each for the NOAA ships RAINIER and RUDE, two for the WHITING launches, and one for the BAY HYDROGRAPHER, which NOAA also uses as a systems test platform.  In addition, NOAA procured a Reson 8125 high-resolution multibeam echosounder for each vessel, and installed a hull-mounted Kongsberg-Simrad EM1002 multibeam echosounder aboard the WHITING.  Ancillary sensors, software, and data storage management purchased to facilitate the use of these systems will help NOAA speed the hydrographic data to the nautical chart.  In determining equipment needs, NOAA placed primary focus on meeting Homeland Security requirements in collaboration with the Naval Oceanographic Office.  This purchase upgrades NOAA's systems to 21^st century technology so that it can continue its mission to produce the navigation products essential to safe and efficient maritime commerce.  NOAA will also continue to develop optimized algorithms and work processes, using these Commercial Off the Shelf products, to share with and transfer to the entire hydrographic industry.  One of the secondary benefits to this upgrade plan is the increased ability to apply these same technologies to the production of large area maps of benthic habitat.  The high-resolution echosounders and side scan sonars will create exciting high-resolution digital terrain models of the underwater environment and provide good estimates of large-scale variations in acoustic backscatter.  Demonstration of sample products will be the focus of the poster session.

CAHOON, L.B. (Cahoon@uncwil.edu)*¹, M.H. POSEY², W.H. DANIELS³, and T.D. ALPHIN²;  ¹ Department of Biological Sciences, UNC Wilmington, Wilmington, NC, ² Center for Marine Science, UNC Wilmington, Wilmington, NC, ³ 302 Tate Road, Belhaven, NC.  Shrimp and crab trawling impacts on estuarine soft-bottom organisms.

This project addressed some possible impacts of trawling for crabs and shrimp in North Carolina estuaries on populations of organisms associated with soft-bottom habitats. The organisms of interest included benthic microalgae, demersal zooplankton, and macrobenthic infauna, encompassing the lower trophic levels in the benthic food chain and the essential trophic coupling that supports estuarine fishery production. The approaches used in this project included sampling before and after experimental trawling at several estuarine locations, sampling in areas actively trawled and areas closed to trawling, and sampling during several seasons over two years to address seasonal and inter-annual effects. Sampling began in February, 1999, and ended in November, 2000 at six locations in the Pamlico River Estuary. Experimental trawling had no significant effect on the biomass of benthic microalgae, no consistent effect on the abundance of demersal zooplankton, and only a slight but non-significant effect on the abundances of benthic macrofaunal animals. Benthic microalgae were significantly more abundant in untrawled locations than in trawled locations, with strong seasonal variation as well. Abundances of demersal zooplankton were not significantly or consistently different between untrawled and trawled locations. There were higher abundances of benthic macrofauna in trawled locations than at untrawled locations, but only at certain times of the year. Species dominance was fairly consistent between trawled and untrawled areas, with only a few exceptions. While inter-annual variation and substrate did have an effect, seasonal variation was far stronger and seemed to have an overriding effect. We conclude that direct, negative impacts of trawling activity on these soft-bottom organisms are small relative to other sources of population variability. The soft-bottom communities we studied experience considerable natural disturbance in these broad, shallow estuarine ecosystems. Although trawling per se does not seem to have a consistent effect on estuarine soft-bottom benthos, there are interesting differences between trawled and untrawled habitats that merit further investigation.

CALDWELL, P. (Phil.Caldwell@noaa.gov)* and P. SHERIDAN, NOAA Fisheries, Southeast Fisheries Science Center, Galveston TX. Data sets relevant to identification of essential fish habitat (EFH) on the Gulf of Mexico continental shelf and for estimation of effects of shrimp trawling gear.

Our objectives were: to identify data describing habitats, shrimp trawling, and other human activities on the Gulf of Mexico continental shelf; to incorporate such data into a GIS format; and to provide preliminary experimental designs for assessment of effects of shrimp trawling on EFH. We developed 57 data layers describing habitat (benthic organism densities, sand/silt/clay, digitized sediment and biotic community maps), structures (bathymetry, State/Federal waters, safety fairways, oil and gas, artificial reefs, bottom obstructions), and fishing (patterns of shrimp fishing effort, experimental trawling sites/catches, closed waters). Best opportunities for experimental trawling in closed waters lie in southern and northwest Florida (permanent closures) and in Texas (seasonal closures). Experiments in open waters need to account for seasonal closures, ambient shrimping effort, and variations in sediments and their associated benthic communities. Cross-Gulf replication is necessary to provide a fishery-wide assessment of gear impacts. Most opportunities for replication exist at depths of 18-27 m for both sand and mud habitats. Moving to waters only as deep as 46-55 m forces experiments to become more regional and less Gulf-wide in nature. Benthic data are most dense off south Texas and Mobile Bay, less dense off Florida, and are largely absent off west Louisiana and north Texas. Non-extractive or no-take marine reserves could be used to study effects of complete cessation of trawling on habitats and fauna (estimating recovery rates of ecosystem components, conducting fishery-free gear impact studies). We present only a few options - data sets are available on CD.

CARBINES*, G.D. (Carbines@storm.cri.nz); National Institute of Water and Atmospheric Research, Dunedin, New Zealand.  The impact of oyster dredging on blue cod in New Zealand.

Little is known about the potential impact of dredging on the growth and abundance of demersal fishes. Observations of blue cod (Parapercis colias) and oyster (Ostrea chilensis) fishing patterns indicate that dredging by the oyster fishery reduced localized catches and changed fishing patterns of blue cod fishers in Foveaux Strait, southern New Zealand. Towed underwater videos were then used to confirm the impact of dredging on habitat complexity and numbers of blue cod. An analysis of the diet and growth of blue cod from undisturbed biogenic reefs and reefs modified by oyster dredging further showed that diet complexity and growth of juvenile blue cod are reduced by dredging for oysters. However, stabilizing dredged habitat with fresh processed oyster shells shows promising signs of regeneration of blue cod populations in only a few years.

CARLSON, P.R. (pcarlson@usgs.gov)*¹, P N.HOOGE², A STEVENSON¹, G COCHRANE¹, and P DARTNELL¹;  ¹U.S. Geological Survey, Menlo Park, CA 94025, ²U.S. Geological Survey, Gustavus, AK. Extensive iceberg reworking of lower Glacier Bay sediments provides unexpected geohabitat.

Complex iceberg gouge patterns were discovered in glacial marine sediment in the lower part of Glacier Bay, Alaska, in water depths ranging from 50-100 m.  Individual gouges are as much as 5 km long, a few tens of meters wide, and with several meters of relief.   Previous acoustic profiling in this part of the bay had not been of high enough resolution or density of coverage to detect the vast area of gouges that were visible on multibeam imagery collected in June 2001.  These gouges were formed by large icebergs that calved repeatedly as the Little Ice-age Glacier, which completely filled the fjord about 200 years ago, retreated up bay.  Massive icebergs with drafts to 100 m calved repeatedly from the glacier, as it retreated up the fjord.  The dominant gouge orientation, roughly parallel to the fjord axis, suggests that the strong tidal currents, up to seven knots through Sitakaday Narrows, were responsible for moving the iceberg keels into and across the seabed.  Surprisingly, the gouges remain unburied in this environment of high sedimentation.  This, in large part, is because the glaciers have retreated more than 80 km up fjord from Sitakaday Narrows, thus the amount of sediment presently reaching the ice gouges is largely restricted to local runoff and plankton debris.  In addition, the >7 knot tidal currents through Sitakaday Narrows, effectively keep the ice-gouged fjord floor scoured clean of fine sediment. This multibeam imagery is being used in our joint study of physical and biological characteristics of benthic habitats (primarily Halibut and Dungeness crab) in Glacier Bay.   The habitat results also will be applied to fisheries problems in southeast Alaska, especially to Marine Protected Areas.

CHANG, S. (Sukwoo.Chang@noaa.gov)*, J. VITALIANO and F. STEIMLE; National Marine Fisheries Service, Northeast Fisheries Science Center, James J. Howard Marine Sciences Laboratory, Highlands, NJ. Habitat and species associations of demersal fish and benthic invertebrates in the New York Bight apex.

The associations among demersal fish and benthic invertebrate species with numerous habitat variables were investigated in the data collected during the 12 Mile Dumpsite Study (12MDS) in the inner New York Bight (July 1986 to September 1989).  The 12MDS study was unique because synoptic measurements were made at numerous levels of the benthic ecosystem over the 39-month study period.  Also, a number of federally managed resource species spend all or part of their life cycle in the inner New York Bight and adjacent estuaries.  Factor analysis and canonical correlation analysis reveal strong to moderate associations among fish species, between fish species and water and sediment quality variables, and between fish species and invertebrate prey species.  Furthermore, strong to moderate associations were also found among invertebrate species and between invertebrate species and water and sediment quality variables. The approach of using multivariate statistical procedures to explore the associations between habitat variables and important resource fish species can be used to better understand the essential fish habitat relationships of these species.

CHIAPPONE, M. (chiapponem@uncwil.edu)* ¹, D.W. SWANSON², and S.L. MILLER¹;  ¹Center for Marine Science and NOAA's National Undersea Research Center, University of North Carolina at Wilmington, Key Largo, FL, ²Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL. Impacts to coral reef benthos from lobster trap gear in the Florida Keys National Marine Sanctuary.

Growth in the Florida Keys fisheries for spiny lobster (Panulirus argus) and stone crab (Menippe mercenaria) has resulted in increased numbers of traps and environmental impacts. During 1998 alone, the stone crab and spiny lobster fisheries were estimated to utilize a total of 750,000 traps and 540,000, respectively. Impacts from gear are exacerbated when traps are lost due to severe storms. This study evaluated the distribution, density, and impacts to coral reef sessile invertebrates from lobster trap gear at 117 sites in the Florida Keys National Marine Sanctuary during 2000 and 2001. Sites were stratified according to benthic habitat type and fishing protection and encompassed 13 of the Sanctuary's 23 no-fishing zones. Diver surveys using transects were performed to document the type, length, and number of biota impacted by lost gear. Surveys yielded 86 incidences of gear totaling nearly 380 m, consisting mostly of buoy lines and wood slats. Densities of gear among the three habitat types ranged from 0.11 to 0.86 incidences/100 m², with four to eight times greater gear density in patch reefs compared to other habitats. The distribution of lobster trap gear did not differ significantly between protected and fished sites. Lobster trap gear, especially buoy lines, caused partial mortality or complete mortality to 152 sessile invertebrates. Relative to hook-and-line gear effects, lobster trap gear impacted sessile invertebrates varied less among the organisms considered. Gorgonians (39%) and scleractinian corals (24%) were the most commonly affected, followed by sponges (17%), colonial zoanthids (13%), and milleporid hydrocorals (7%).

CHIAPPONE, M. (chiapponem@uncwil.edu)*¹, D.W. SWANSON², and S.L. MILLER¹;  ¹Center for Marine Science and NOAA's National Undersea Research Center, University of North Carolina at Wilmington, Key Largo, FL, ²Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL. Spatial distribution and benthic impacts from hook-and-line fishing gear in the Florida Keys National Marine Sanctuary.

The spatial distribution and impacts to coral reef benthos from hook-and-line fishing gear were assessed at 117 sites spanning 2000 km in the Florida Keys National Marine Sanctuary during the summers of 2000 and 2001. Sites were stratified random with respect to habitat type and fishing protection. Surveys encompassed patch reef, spur and groove, and hard-bottom habitat types from 3 m to 12 m depth within and adjacent to 13 of the Sanctuary's 23 no-fishing zones. Diver surveys using transects were performed to document the type, length, and number of biota impacted by hook-and-line gear. From surveys of 34,000 m² of benthic habitat, 361 incidences of gear totaling nearly 465 m were documented, yielding a domain-wide density of 1.06 incidences/100 m². Gear densities ranged from 0.82 to 1.35 incidences/100 m² among the habitat types. In patch reef and spur and groove habitats, no significant differences were detected in the distribution of gear between protected and fished sites, while protected areas in the hard-bottom habitat yielded more gear than expected. Hook-and-line gear caused partial mortality or complete mortality to 434 sessile invertebrates. Organisms with upright morphologies such as gorgonians (47%), sponges (18%), and milleporid hydrocorals (18%) were the most frequently affected. Organism density, gear density, and gear length are some of the factors influencing gear impacts. For the habitats surveyed, hook-and-line gear is spatially pervasive in the Florida Keys, indicates a pattern of non-compliance with no-fishing regulations, and represents a low-level stressor to sessile reef invertebrates.

CHIARAPPA, M.J. (michael.chiarappa@wmich.edu), Western Michigan University, Great Lakes Center for Maritime Studies, Kalamazoo, MI. Occupational endurance and contested resources: managing the cultural and economic tensions of Lake Michigan's commercial fishery.

The establishment of commercial fishing in the Great Lakes in the 19^th century introduced unprecedented economic considerations and ecological effects to the basin's benthic habitats. By the late 19th/early 20^th century, the alarming effects of overfishing this region's benthic speciesÑmost of which were the principal target species (lake whitefish, lake trout, perch, walleye, chub) of the Great Lakes commercial fisheryÑwas increasingly apparent to fisheries scientists and policy makers. The Great Lakes commercial fishery managed to weather these stock fluctuations until the end of World War II when the combined ecological effect of overfishing, sea lamprey predation, and a disproportionate alewife population dangerously reduced benthic dwelling species. With the exception of lake trout, benthic species have recovered over the past 50 years. But commercial fishers, particularly Lake Michigan's, have not necessarily enjoyed the benefits of this recovery. As Great Lakes states revised their fisheries policies to enhance sport fisheries, commercial fishers faced stringent restrictions in their harvesting technologies, in their fishing areas, and in the implementation of quotas. Today, in spite of highly contested policy debates, Lake Michigan's benthic fisheries are comprised of two constituencies that visibly utilize benthic habitats to maintain distinct cultural prerogatives and economic goals. Euroamerican commercial fishers draw on their cultural life, traditional ecological knowledge (TEK), and a legacy of economic adaptation to maximize their limited share of the benthic realm. Native American fishers, motivated by the maintenance of treaty fishing rights, are using the benthic realm for economic empowerment and the recovery of tradition-bound cultural/ecological awareness. Looking at TEK and the formulation of vernacular environmental ethics, this paper will consider the benefits and problems that have accrued to each group's attempt to utilize Lake Michigan's benthic habitat to achieve historical and contemporary goals.

CHIARELLA, L.A. (Lou.Chiarella@noaa.gov)*¹, D.K. STEVENSON¹, C.D. STEPHAN¹, R.N. REID², J.E. McCARTHY², M.W. PENTONY³, T.B. HOFF⁴, C.D. SELBERG⁵, and K.A. JOHNSON⁶;  ¹National Marine Fisheries Service, Northeast Regional Office, Gloucester, MA, ² National Marine Fisheries Service, Northeast Fisheries Science Center, Highlands, NJ, ³New England Fishery Management Council, Newburyport, MA, ⁴Mid-Atlantic Fishery Management Council, Dover, DE, ⁵Atlantic States Marine Fisheries Commission, Washington, DC, ⁶ National Marine Fisheries Service, Office of Habitat Conservation, Silver Spring, MD.  Results of a workshop on the effects of fishing gear on benthic habitats off the Northeastern United States.

A panel of experts in the fields of benthic ecology, fishery ecology, geology, fishing gear technology and operations were convened in October 2001 to assist the Northeast Region's fishery management councils in evaluating the effects of fishing gear on local benthic habitats and identifying potential management measures. The panel expressed greatest overall concern about impacts from otter trawls and scallop dredges to structure forming organisms.  Gravel habitat was considered to be most at risk from gear impacts, followed by sand and mud habitats.  In some circumstances the extent of impact in each habitat varied based on the environment's energy level (high vs. low energy).  In general, bottom tending mobile gear was of greater concern than fixed gear.  Clam dredges were rated as having the least effect of the mobile gears because of the limited geographic area and the rapid recovery rates of the high energy sand environment in which they are fished.  Scallop dredges were rated as having large effects in the gravel and sand habitats in which they are fished. Panelists had the greatest difficulty reaching consensus on the impacts of otter trawls due to their widespread use over a large variety of habitat types as well as the numerous gear configurations employed.  The three primary management measures proposed to reduce fishing gear impacts included effort reductions, spatial closures, and gear modifications.

CLARK, M.R. (m.clark@niwa.cri.nz)*, A.A ROWDEN, and S.O'SHEA; National Institute of Water & Atmospheric Research, Wellington, New Zealand.  Effects of fishing on the benthic habitat and fauna of seamounts on the Chatham Rise, New Zealand.

Major deepwater trawl fisheries occur for orange roughy on seamounts in New Zealand waters. These seamounts are often small, and trawling can be concentrated in a very localised area. Seamount habitat is thought to be productive, but also fragile, and there is growing concern from fisheries managers, environmental groups, and the fishing industry about effects of fishing on biodiversity and ecosystem productivity. This has prompted research to examine the nature and extent of deepwater trawling impact on seamount habitat in New Zealand. Results are presented from a recent survey where video and still imagery were applied to classify benthic habitat, and a new robust epibenthic sled used to sample the deepwater fauna. The study took place on the Chatham Rise where a group of 8 seamounts in close proximity allowed for a spatially unconfounded comparison of replicated fished and unfished seamounts. Commercial fisheries data were analyzed to determine the amount of trawling on each. Similarities within, and differences between, fished and unfished seamounts were identified for distribution of trawl gear modification of habitat; extent of live coral; macroinvertebrate assemblage composition, taxonomic distinctness and size spectra . This study provided information to help plan management strategies and develop effective management practices to allow both conservation and exploitation of seamounts, although more research is required. In May 2001, 19 seamounts throughout the New Zealand region, including several features on the Chatham Rise, were closed to bottom trawling as a precautionary measure.

CLAYTON, T.D. (tclayton@usgs.gov)*¹, J.C. BROCK¹, and C.W. WRIGHT²;  ¹U.S. Geological Survey, Center for Coastal and Regional Marine Studies, St. Petersburg, FL, ²Laboratory for Hydrospheric Processes, NASA, Goddard Space Flight Center, Wallops Island, VA. Mapping seagrass boundaries with waveform-resolving lidar:  a preliminary assessment.

For ecologists and managers of seagrass systems, the spatial context provided by remote sensing has proven to be an important complement to in situ assessments and measurements.  The spatial extent of seagrass beds has been mapped most commonly with conventional aerial photography.  Additional remote mapping and monitoring tools applied to seagrass studies include optical satellite sensors, airborne multispectral scanners, underwater video cameras, and towed sonar systems.  An additional tool that shows much promise is airborne, waveform-resolving lidar (light detection and ranging).  Now used routinely for high-resolution bathymetric and topographic surveys, lidar systems operate by emitting a laser pulse, then measuring its two-way travel time from the plane to reflecting surface(s) below, then back to the detector co-located with the laser transmitter.  Using a novel, waveform-resolving lidar system developed at NASA -- the Experimental Advanced Airborne Research Lidar (EAARL) -- we are investigating the possibility of using the additional information contained in the returned laser pulse (waveform) for the purposes of benthic habitat mapping. Preliminary analyses indicate that seagrass beds can potentially be delineated on the basis of apparent bathymetry, returned waveform shape and amplitude, and (horizontal) spatial texture.  A complete set of georectified digital camera imagery is also collected during each EAARL overflight and can aid in mapping efforts.  Illustrative examples are shown from seagrass beds in the turbid waters of Tampa Bay and the relatively clear waters of the Florida Keys.

COCHRANE, G. R. (gcochrane@usgs.gov); U.S. Geological Survey, Menlo Park, CA.  Mapping rocky habitat using textural analysis of sidescan sonar images.

Highly reflective seafloor features imaged by sidescan sonar in nearshore waters off the Northern Channel Islands (California, USA) have been observed in subsequent submersible dives to be areas of thin sand covering bedrock.  Adjacent areas of rocky seafloor, suitable as habitat for endangered species of abalone and rockfish, and encrusting organisms, can not be differentiated from the areas of thin sand on the basis of acoustic backscatter (i.e. gray level) alone.  We found second order textural analysis of sidescan sonar data useful to differentiate the bottom types where data is not degraded by near-range distortion (caused by slant range and ground range corrections), and where data is not degraded by far-range signal attenuation.  Hand editing based on submersible observations is necessary to completely convert the sidescan sonar image to a bottom character classification map suitable for habitat mapping.

COGGAN, R.A. (r.a.coggan@cefas.co.uk)*^1,2,4, C.J. SMITH³, R.J.A. ATKINSON², K.-N. PAPADOPOULOU³, T.D.I. STEVENSON², P.G. MOORE² and I.D. TUCK⁴;  ¹CEFAS Laboratory, Essex, United Kingdom, ²University Marine Biological Station, Millport, Isle of Cumbrae, Scotland, United Kingdom, ³Institute of Marine Biology of Crete, Iraklio, Crete, Greece, ⁴Fisheries Research Services Marine Laboratory, Aberdeen, Scotland, United Kingdom. Fast-track methods for assessing trawl impacts.

Traditional methods for assessing the impact of towed demersal fishing gear are notoriously slow, taking years to report and imposing undesirable delays in the provision of scientific advice on which fisheries and environmental managers can act. There is a need to develop rapid methods for assessing trawl impacts.  We evaluate and compare a suite of rapid methodologies covering a range of readily accessible technologies including:

1. Acoustic methods: sidescan sonar and bottom discriminating sonar (RoxAnn™);
2. Visual methods: towed video sledge and ROV;
3. Faunal sampling (epibenthic megafauna): tissue damage, community analysis, population density, functional group composition; and
4. Sedimentology: granulometry, geotechnical properties and sediment profile imagery.

These methods were applied to otter trawl fisheries in the Clyde Sea, Scotland and the Aegean Sea, Mediterranean, at sites representing a range of trawl impacts. Novel methods of analysis were developed for quantitative interpretation of sidescan and video records. The scientific effectiveness, cost effectiveness and operational constraints of the various methodologies are reviewed. We recommend suitable approaches to the rapid assessment of trawl impacts taking into consideration the variety of resources (such as time, equipment and budget) which may be available. Assessments should employ complementary methods that operate on different scales of resolution (eg. sidescan sonar with either faunal sampling or ROV). Site-specific factors, such as topography and substratum type, will influence choice of methods and survey design. These rapid methodologies can provide results in a matter of days or weeks rather than the months or years associated with traditional assessment methods.

COLEMAN, F. C. (coleman@bio.fsu.edu)*¹, C. C. KOENIG¹, M. W. MILLER², S.A. HEPPELL³, S. S. HEPPELL³, and K. SCANLON⁴;  ¹Department of Biological Science, Florida State University, Tallahassee, FL, ²National Marine Fisheries Service, Miami, FL, ³Oregon State University, Department of Fisheries and Wildlife, Corvallis, OR, ⁴U. S. Geological Survey, Woods Hole, MA.  Fishing effects on habitat: the potential consequences of removing such habitat engineers as red grouper (Epinephelus morio). 

Mass removal of species that restructure the architecture of habitat and thus increase its complexity can have multiple effects on ecosystems, including loss of biodiversity and altered biogeochemical pathways. In this paper, we report on the contributions made to habitat heterogeneity by the engineering capabilities of red grouper, Epinephelus morio, throughout its life.  We demonstrate that this fish starts excavating habitat at first settlement, provides important structure and enhances biodiversity in nearshore communities of the west Florida shelf as juveniles, and contributes significantly to the structure of low-relief continental shelf edge areas as adults.  We discuss the potential benefits of using side-scan sonar imagery to track grouper-induced changes in habitat over time (developing a time-series of images both within marine reserves and in nearby reference sites).  We also discuss the implications of red grouper fishery removals to overall productivity of the continental shelf of the northeastern Gulf of Mexico and the particular management problems presented by knowledge of this behavior.  Current management decisions to move the longline grouper fishery further offshore may increase pressure on red grouper and other excavating species, such as tilefish, have a significant negative influence on habitat heterogeneity, with potential to cause cascading problems throughout shelf-edge communities.

COLLIE, J. (jcollie@gso.uri.edu)*¹, J. HERMSEN¹, and P. VALENTINE²;  ¹Graduate School of Oceanography, University of Rhode Island, ²U.S. Geological Survey, Woods Hole, MA.  Effects of fishing on benthic habitats: assessment and recovery.

Habitat disturbance by mobile fishing gear has been identified as one of the most pervasive ecosystem effects of fishing.  However, the degree of effect depends on gear type, habitat type, and other factors. To quantify these differences, a meta-analysis of published fishing impact studies was undertaken.  This analysis showed that intertidal dredging and scallop dredging have the greatest initial effects on benthic biota, while trawling has less initial effect.  Fauna in stable gravel, mud, and biogenic habitats are more adversely affected than those in less consolidated coarse sediments.  Recovery rate appears most rapid in these less physically stable habitats, which are generally inhabited by more opportunistic species. The general paradigm about how fishing ought to affect benthic communities is generally supported, but there remain substantial gaps in the available data, which urgently need to be filled. Our own field studies have focused on the gravel sediment habitat on the northern edge of Georges Bank, which is an important nursery area for juvenile fish.  On cruises to this area since 1994, we have collected dredge samples and photographs from sites of varying depths and with varying degrees of disturbance from otter trawling and scallop dredging.  Compared with the disturbed sites, the undisturbed sites have higher numerical abundance, biomass, and species diversity of benthic megafauna.  Undisturbed sites also have higher percent cover of colonial epifauna, which provide a complex habitat for shrimp, polychaetes, brittle stars, and small fish.  Since 1995 we have been monitoring the recovery of a previously disturbed area that was closed to bottom fishing in December 1994.  We have observed significant increases in abundance (x8), biomass (x7), production (x4), and epifaunal cover in the closed area.  Results of our study have been used by the New England Fishery Management Council to designate a Habitat Area of Particular Concern for juvenile cod.

COTTERELL S.P. (s.cotterell@plymouth.ac.uk); Institute of Marine Studies, University of Plymouth, Drake Circus, Plymouth, United Kingdom. Fish landings, discards and benthic material from otter trawling in the western English Channel.

A fleet-stratified sampling design was employed between 1998 and 2000 to study fish discards and landing and to quantify the other incidentally caught material.  The studied techniques were <12m single boat otter trawling, <12m paired demersal trawling and >12m single boat otter trawling.  Trips for <12m ranged from one to three days while those for >12m boats were one to six days.  These boats operated out of the four principle English ports of ICES area VIIe, western English Channel.  On board the boats and prior to any sorting by the crew a sample (~40kg) of the catch was taken and all fish were identified and measured, and their fate (whether to be landed or discarded) was noted.  All non-fish material was stored in the fish hold for later detailed analysis.  The non-fish material was categorised as benthos, or biogenic, inorganic, or anthropogenic material.  The benthos was classified, weighed and measured.  Also, a system to assess its degree of damage was developed, allowing length-weight regressions to be generated for the more common invertebrate species.  On average 60% (by weight) of the haul was landed, 10% was bait fish, 20% was discarded and 10% was non-fish material.  Landing samples were compared to confidential catch composition figures of trip landings.  British Geological Survey data was used to assess the substrate over which the trawl had passed and benthos composition was compared to historical data sets.   From this study it would appear that economic overfishing would occur before irreparable benthic disturbance for these techniques.

CRAEYMEERSCH, J.A. (johan@rivo.wag-ur.nl)* and G.J. PIET; Netherlands Institute for Fisheries Research. Changes in the epibenthos assemblages of the North Sea following the establishment of a protected area, the "plaice box". 

In 1989 a protected area in the south-eastern North Sea was established: the 'plaice box'.  Data of the by-catch of annual beam trawl surveys carried out since 1985 will be used to determine the effect of the changes in fishing effort. A first analysis showed significant changes in the species composition after the 'closure' of the box. Changes, however, also occurred in the reference area (although in other species), suggesting that in addition to changes in impact by bottom fishing gear, other (climatic?) variables may have been involved. We will present the results of further analysis using multivariate techniques. Changes in species composition in the box area and in a reference area will be related to changes in fishing effort, environmental variables and climate.

CRANFIELD, H.J. (j.cranfield@niwa.cri.nz)*¹, K.P. MICHAEL¹, G.CARBINES², D.P. GORDON¹, B. MANIGHETTI¹, A. DUNN¹, and A.A. ROWDEN¹;  ¹National Institute of Water and Atmospheric Research Ltd, Kilbirnie, Wellington, New Zealand, ²National Institute of Water and Atmospheric Research Ltd, Dunedin, New Zealand. Effects of 135 years of oyster (Ostrea chilensis) fishing on the benthic habitat, associated macrofaunal assemblages, and sediments of Foveaux Strait, southern New Zealand.

Management of the oyster fishery, and understanding of the impact of this longstanding fishery on the benthic environment, has been facilitated through periodic surveys. Fishers' and institutional fishing records and the results of biological, acoustic, and sediment surveys have been analysed to show how historical changes to benthic habitat relate to fishing. The seafloor once consisted of bioherms, hundreds of metres wide and many kilometres long, aligned with the tide, separated by similarly wide swaths of relict pebble-gravel sediment. The macrofauna of bioherms was dominated by bryozoa, (over 200 species), and bivalve molluscs, (over 60 species). Oysters were localised on this habitat alone which was also important for blue cod, Parapercis colias. Much biohermal epifauna was removed as bycatch of the oyster fishery and oysters were subsequently depleted locally more rapidly. Bioherm habitat was important in the formation of biogenic sediments and the recruitment, growth, and survival of both oysters and blue cod. The expansion of relict pebble gravel seafloor with the erosion of biohermal sediments relates directly to areal expansion of fishing as oyster beds were serially depleted. Mytilid bivalves and styelid tunicates are identified as early colonisers of regenerating bioherms, and helical circulation patterns in the tidal flow are implicated in the formation of these linear structures within which fine sediments again begin to accumulate. Regeneration of habitat and rebuilding of oyster and blue cod populations in the absence of oyster dredging suggest that MPAs and rotational fishing could be effective in conserving both habitat and fisheries.

CRYER, M. (m.cryer@niwa.cri.nz)*, B. HARTILL, and S. O'SHEA; National Institute of Water and Atmospheric Research, Auckland, New Zealand.  Deepwater trawl fisheries modify benthic community structure in similar ways to fisheries in coastal systems.

Off north-eastern New Zealand, the Bay of Plenty continental slope supports bottom trawl fisheries for gemfish (Rexea solandri), hoki (Macruronus novaezelandiae), tarakihi (Nemadactylus macropterus), and, most recently scampi (a burrowing, deep-water lobster, Metanephrops challengeri). Excellent information has been collected since 1988 on the distribution of trawling effort in these fisheries, including the start and finish location of each trawl tow with a precision of 1 minute of latitude and longitude. Using a GIS, we linked these data to information on the invertebrate bycatch of 66 research trawls, and explored the extent to which the composition of our bycatch (as one index of benthic community structure) could be explained by the frequency of trawling at a given site. Using multivariate ordination techniques, we explained up to 65% of variation in the distribution of species among samples, more than half of which was attributable to our indices of trawling (mainly for scampi and gemfish). Qualitatively, the inferred effects of deep-water trawling were similar to those of coastal fisheries; increasing fishing activity was associated with reductions in species richness, diversity, and the abundance of large or fragile taxa. The gross quality of information on fishing effort has hitherto been a major constraint on our understanding of the effects of fishing. This study is one example of the way good quality information at the right (fine) scale can further that understanding, but comprehensive information on the distribution of fishing effort may also allow extrapolation of experimental studies to the wider scale of fisheries management.

CUTTER, G. R. (gcutter@cisunix.unh.edu)*¹, L. A. MAYER¹, Y. RZHANOV¹, and R. GRIZZLE²;  ¹University of New Hampshire, Center for Coastal and Ocean Mapping, Durham, NH, ² University of New Hampshire, Jackson Estuarine Laboratory, Durham, NH. Quantitative ground-truthing of biological habitat characteristics using video mosaic images.

Benthic habitats from the Piscataqua River, New Hampshire, have been delineated using bathymetry derived from multibeam echosounder data, an increasingly common methodology.  In addition to the standard approach of manual interpretation and delineation, we have implemented automated methods for distinguishing regions of different acoustic character.  Despite the good agreement between the resultant delineations using manual and automated methods, we suggest that acoustic data depicts the physical habitat model (PHM) of the seafloor and therefore any such delineation may have limited utility for directly characterizing fauna.  The pending issue is how the acoustic-derived physical habitat model represents the biological components of the system.  By assuming organism-substrate interaction relationships, a functional biology model can be developed to link the PHM to fauna, however, without ground-truthing data such models are merely conjectural.  Two methods of ground-truthing habitat delineations are common:  core or grab samples, and still camera or video imagery.  There is a disparity between biology represented by acoustic and optical imaging and direct samples.  There is also a disparity between what different optical imagery techniques represent.  We show that common imaging techniques can misrepresent fauna and biological habitat characteristics for substrates with no apparent biological features or sparsely distributed fauna.  We describe the use and analysis of video mosaics as an imaging technique for representing microhabitat characteristics and macrofauna as well as larger, sparsely distributed organisms.  We relate those results to how the PHM represents certain fauna.

DEALTERIS, J.T. (jdealteris@uri.edu)* and L. G. SKROBE; Department of Fisheries, University of Rhode Island, Kingston, RI.  A paradigm for the management of fish habitat based on vulnerability and availability, and an assessment of the impact of fishers on habitat and habitat protection on fishers.

Fish habitat on the continental shelf of the northeast United States was evaluated along three strip transects for vulnerability or resilience to and frequency of disturbance by mobile-fishing gear, and the relative availability. Each study area, approximately 50x150 km, was sub-divided into 10x18 km sub-areas for data analysis.  Habitat value has been directly related to structural complexity, and indirectly related to substrate stability.  Sediment and bottom current data were used to assess substrate stability in each sub-area. The relative availability of each habitat type within each study area was also estimated from the sediment distribution data. Fishing effort data for mobile fishing gears within each sub-area were averaged over an 11-year period to estimate the area impacted by each gear type annually.  A management paradigm based on the premise that the priority for habitat protection is directly related to habitat vulnerability and inversely related to habitat availability, is proposed. On Georges Bank, areas of vulnerable and spatially limited gravel-cobble habitat were intensely fished, indicating that dredge and trawl fisheries in these areas are problematic for the conservation of fish habitat. Protection of these habitats will impact those fishers that target that habitat. Other areas on Georges Bank are minimally impacted by fishers, and are also resilient habitats. In the southern New England and mid-Atlantic study areas, the nearly ubiquitous and resilient sand habitat was intensely fished in localized areas and minimally in other areas. Since this habitat requires minimal protection, there will be minimal impact on fishers.

DEW, C. B. (braxton.dew@noaa.gov)* and R. A. McCONNAUGHEY; National Marine Fisheries Service, Alaska Fisheries Science Center, Seattle, WA. Did bottom trawling in Bristol Bay's red king crab broodstock refuge contribute to the collapse of Alaska's most valuable fishery?

The 1976 Magnuson Act effectively eliminated the Bristol Bay no-trawl zone known as the Pot Sanctuary. Implemented by the Japanese in 1959, the boundaries of this refuge closely matched the well-defined distribution of the red king crab population's mature-female broodstock, thus affording a measure of protection to the reproductive potential of the stock. In 1980, the point at which the commercial harvest of Bristol Bay legal male red king crab had reached an all-time high after a decade-long increase, domestic bottom trawling in the broodstock sanctuary began with the advent of a U.S.-Soviet, joint-venture, yellowfin sole fishery. As the number of unobserved, domestic trawls in the broodstock area increased rapidly after 1980, and anecdotal reports of 'red bags' (trawl cod-ends plugged with red king crab) began to circulate, the proportion of males in the mature population (0.25 in 1981 and 0.16 in 1982) jumped to 0.54 in 1985 and 0.65 in 1986. It is unlikely that normal demographics caused this sudden reversal in sex ratio. Our hypothesis is that alternating, sex-specific sources of mortality were at work. Initially there were ten years (1970-1980) of monotonically increasing, male-only exploitation, followed by a drastic reduction in the male harvest after 1980 (to zero in 1983). Also beginning in 1980, there was an increase in bottom trawling among highly aggregated, sexually mature females residing within a previously protected area known to be the primary broodstock habitat and the most productive spawning ground for Bristol Bay red king crab. There has been considerable discussion about possible causes (e.g., meteorological regime shifts, epizootic diseases) of the knife-edge collapse of the Bristol Bay red king crab population in the early 1980s. Our discussion will focus on the temporal and spatial nexus between the population's collapse and the onset of large-scale commercial trawling within the population's primary reproductive refuge.

DOOLITTLE, D.F. (danield@vims.edu)*¹, M.R. PATTERSON¹, Z-U. RAHMAN², and R. MANN¹;  ¹College of William and Mary, School of Marine Science at the Virginia Institute of Marine Science, Gloucester Point, VA, ²College of William and Mary, Department of Computer Science, Williamsburg, VA. Decreasing habitat disturbance by improving fish stock assessments: a new method of remote species identification and quantification.

A direct link exists between the quality of fisheries data and the effectiveness of fisheries management.  Increasing the quality and quantity of data on which stock assessments and management decisions are based has been cited as a critical national issue (National Research Council, 2000. Improving the Collection, Management, and Use of Marine Fisheries Data. National Academy Press, Washington, D.C.).  We approach the challenge of limiting deleterious habitat impacts due to fishing through the creation and demonstration of novel stock assessment and habitat visualization tools.  We present here a new method of fish species identification and quantification.  The technique uses a Radial Basis Function artificial neural network classifier to discriminate and enumerate selected fish species from high-resolution side scan sonar images.  We demonstrate this technology onboard a Fetch! class Autonomous Underwater Vehicle (AUV) and provide examples of how such technologies could augment fisheries stock assessment as well as essential fish habitat determination.  Ancillary benefits of this technology include the opportunity to simultaneously characterize surficial bottom types and document habitat utilization by species that are known to the classifier.  Such side scan sonar species identification tools would significantly augment current stock assessment methods, provide new insight to habitat usage, and allow more ecologically realistic models to be constructed.

DOUNAS C. (kdounas@imbc.gr)*¹, J. DAVIES², P. HAYES², C. ARVANITIDIS¹, and P. KOULOURI¹;  ¹Institute of Marine Biology of Crete, Greece, ²Fisheries Research Services, United Kingdom. The affect of different types of otter trawl groundrope on benthic nutrient fluxes and sediment biogeochemistry.

The direct impacts of seabed disturbance by otter trawling on the rate of nutrients' regeneration from the sediment to the overlying water column, and on the biogeochemical sediment zonation, have never been studied. These impacts can have very important implications for nutrient supply, and hence on primary production in the continental shelf where most trawling activity is concentrated, and consequently on fish production and fishing management. The labile fractions of sedimentary organic matter, responsible for most sedimentary metabolism, are usually concentrated on or near the sediment surface. Consequently the impact of trawling on sediment biogeochemistry could be studied by the artificial disturbance of the sediment surface layer. The part of a trawl rig that mostly contributes to this process is the groundrope (more than 90% of the total conduct surface) which was finally chosen for carrying out of trawling simulation experiments. The site selected was the continental shelf of Heraklion Bay (Eastern Mediterranean, Cretan Sea). Artificial nutrient fluxes were measured by applying a trawling simulating sampler. Five different groundrope settings were used in order to estimate potential quantitative differences in sediment biogeochemistry and nutrient releases derived from the conduct of the groundrope with the seabed. Statistical comparison of the results revealed that almost all biological active compounds at the sediment surface are resuspended by a single passage of the simulating gear. The implication is that the upper extremely thin layer of sediments contains a considerable reservoir of dissolved and particulate nutrients in concentrations, much higher than in the underlying sediment layers.

EMELYANOV V.A. (evasea2002@yahoo.com); First Deputy Chief of the Natural Academy of Sciences of Ukraine, and Institute of Geologycal Sciences of the National Academy of Sciences of Ukraine, Kyiv, Ukraine.  The theoretical and methodological basis of estimations of the human-made influences (fishing and constructing) on the benthic habitats.

In the last few decades, human-made influences have considerably increased on the upper part of lithosphere within the World Ocean's bounds as the benthic habitat.  Some scientific directions have attempted to solve numerous benthic habitat problems related to increasing fishing and construction activities. But it is impossible to do this effectively within the limits of traditional scientific directions, resulting in the need to incorporate more ecological sciences with these traditional scientific approaches to investigations and estimations of the growing problems and the search for solutions. In particular, more and more explorations have concentrated their attention on the many-sided investigations of the compound characteristics of benthic habitats as a marine geo-ecological system.  But many terminological, conceptual, methodological and other general questions have arisen from these studies. Without answers to these questions, it is difficult to solve many specific problems related to human-made influences on benthic habitats, as well as the creation and steady development of marine and coastal areas. In this paper, some new terms are presented, with their treatments, basic conceptions and approaches, that are more applied in the modern benthic habitat's investigations and become an important component of the theory and methodology of a new scientific directionÑmarine geo-ecology, of studying and solving many benthic habitat problems related to fishing and construction activities.

ENS, B.J. (b.j.ens@alterra.wag-ur.nl)*¹, A.C. SMAAL² and J. DE VLAS³;  ¹Alterra, Texel, The Netherlands, ²RIVO-CSO, Yerseke, The Netherlands, ³RIKZ, Haren, The Netherlands.  Fishing for shellfish in an internationally important nature reserve: do current policies achieve their objectives?

The Dutch Wadden Sea is a nature reserve of international significance. Fishing for shellfish is allowed as long these activities do not cause significant harm to the natural values of the area. In 1993 this objective was implemented in a new shellfishing policy via two management policies: closed areas and food reservation. Thus, 26% of the intertidal mudflats are permanently closed for fishery to restore important habitats, particularly intertidal mussel beds and seagrass beds. To prevent food shortages for shellfish eating birds, mainly oystercatchers and eider ducks, caused by shellfish fishery, fishing for shellfish is not allowed when shellfish stocks are below a threshold value. In 2003, this new shellfishing policy must be evaluated. To this end, a major research program was initiated. It includes testing the hypothesis that mechanised fishing for cockles has long-term negative effects on the recruitment of cockles and other bivalves mediated by a loss of fine sediments. It also includes detailed investigations whether declining numbers of oystercatchers and recent high mortality among eider ducks can be related to food shortages and if so, whether these food shortages are linked to the current shellfishing practices. While the program relies heavily on massive long-term monitoring of shellfish stocks, shellfish fishery (including continuous registration of all fishing activities), benthic habitats and bird numbers in combination with mathematical modelling, some field experiments are also conducted. Most notable is an experimental test of the hypothesis put forward by the fishermen that fishing on mussel seedbeds helps to stabilise these beds. Preliminary results of the project will be discussed.

ESCOBAR-BRIONES, E. (escobri@mar.icmyl.unam.mx)*¹, A. GRACIA¹, and G. T. ROWE²;  ¹Unidad Académica Sistemas Oceanogr‡ficos y Costeros, Instituto de Ciencias del Mar y Limnologia, Universidad Nacional Aut—noma de México, Mexico, ²Department of Oceanography, Texas A&M University, College Station, TX.  Understanding chronic and event driven natural change to benthic habitats (physical/biological): effect of sediment disturbance on sediment community oxygen consumption (SCOC).

Sediment variables and changes in infaunal ratio have been known to determine the rates of sediment community oxygen consumption. Habitat disturbance may affect SCOC by changing the seafloor surface by resuspension or smoothing and the ratios of size, species composition, abundance and biomass of the infaunal components. Estimates of SCOC were made at 15 localities of soft-bottom sediments of the shelf and margin of the SW Gulf of Mexico in which trawling efforts vary from null (Campeche Bank), intermediate (Tamaulipas shelf) to high (Campeche Bay) in an extended time span. Oxygen demand was measured on board in replicated (n=4) experimental incubation chambers. Environmental conditions were maintained during the experiments. The SCOC rates were highest in the Campeche Bank where meio and macrofauna was dominant. Local SCOC differences were significant in both the Campeche Bank and Bay (Newman-Keuls p< 0.05) and were explained by depth (r=0.96), sediment mean grain size (r=0.61) and nitrogen content in sediment (r=0.58) accounting for 95.3% of the variance. SCOC was positively correlated with the infaunal biomass [r=0.71, F (3,29)=9.69 p<0.00014], and bacteria (p= 0.00047) both in the Campeche Bay and the Tamaulipas shelf. Results from multivariate analyses allow us to recognize that disturbance on the seafloor has an indirect effect on the SCOC, the change in ratios of occurrence of bacteria, meio and macrofaunal and organic matter content explain the differences found in SCOC among the three regions.

FIELD, M.E. (mfield@usgs.gov); Pacific Science Center, U.S. Geological Survey, Santa Cruz, CA.  Living with change: response of the sea floor to natural events.

Natural processes are a vital, inseparable component of the biosphere. Their causes, scales, and interactions are complex, and all habitats, such as shallow marine benthic habitats, evolve in accord with the prevailing natural processes. Long term community structure and trophic patterns develop in response to both chronic processes, such as dominant currents and wave stresses, and intermediate-scale event-driven processes. All processes, including individual biologic functions (e.g. foraging, burrowing) locally disturb the sea floor, but do they not necessarily impact or change the sea floor. Disturbances are essential for maintenance of the habitat through such diverse functions as delivery of nutrients, oxygenation, and introduction of food. The suite of natural processes ultimately controls all of the physical parameters, such as particle size and organic content, and many biologic ones, such as survivability of sessile organisms and continuity of substrate type. In short, every habitat represents a time-averaged response to the dominant physical processes, which are as important in defining the habitat as geologic setting and community structure.  Do natural processes negatively impact habitats? Only, it appears, at the largest scale, and then only locally. It is not the process that affects a habitatÑit is a change in the magnitude or frequency that results in a negative impact. Events such as large storm waves that occur infrequently (i.e. decadal scales) are termed 'intermediate events' (Connell, 1978). Intermediate events open up new niches for colonizing species and increase habitat diversity. Natural events are of major importance for 'resetting the clock' on individual habitats. In contrast, stable habitats (those undisturbed by intermediate events) tend to evolve toward a climax succession whereby the most successful competitor dominates the community. The community structure of many habitats reflects the occurrence of natural intermediate events. Extreme/rare events, on the other hand, have a pronounced impact on a habitatÑlocal devastation. Examples of extreme events include the 1972 fresh water flooding of Chesapeake Bay; covering of Hawaiian coral reefs by lava; and removal of entire habitats by landslides. Yet, since extreme events tend to occur as local phenomena, they are not all that important to habitat survival because most of the habitat remains preserved. Re-population or replacement is probable because of the abundance of undisturbed genetic stock and the length of time before occurrence of another event of similar magnitude.

FIELD, J.M. (JField@ci.pacific-grove.ca.us)*¹, M.M. YOKLAVICH², G.M. CAILLET¹, S. BROS³, J. deMARIGNAC¹, and R.N. LEA⁴;  ¹Moss Landing Marine Laboratories, Moss Landing, CA, ²National Marine Fisheries Service Tiburon Lab, Santa Cruz, CA, ³San Jose State University, San Jose, CA, ⁴California Department of Fish and Game, Monterey, CA. Small-scale analysis of subtidal fish guilds and associated habitat characteristics along central California.

Recent declines in fish populations are prompting revisions and alterations to current fishery management policies.  One alternative is the establishment of Marine Protected Areas (MPAs) to promote the recovery of fish stocks.  However, before MPAs can be created, habitat associations of the fishes designated for protection need to be characterized to ensure that the ideal habitat can be included when MPAs are designated.  Once the habitat associations of each species are known, remote-sensing technology, such as sidescan sonar, can be used to survey large-scale areas to identify potential habitat for MPAs.  In the Eastern Temperate Pacific, rockfishes (Sebates spp.) are slow growing, have a late age-at-maturity and specific habitat affinities.  These life history characteristics make them especially susceptible to fishing pressure and ideal candidates for protection through MPAs.  To assess habitat associations of fishes within the Big Creek Ecological Reserve, central California, we conducted submersible dives to identify habitat at the meter scale and quantify fish populations.  Multivariate statistical analysis revealed distinct habitat associations for several rockfish species.  In addition, distinct seafloor features were identified as unique habitats at the meter scale.

FRANK, J.E. (jef0926@mail.ecu.edu)*¹, D.R. CORBETT¹, T. WEST², L. CLOUGH², and W. CALFEE³;  ¹Department of Geology, East Carolina University, Greenville, NC, ²Department of Biology, East Carolina University, Greenville, NC, and ³Coastal Resource Management Program, East Carolina University, Greenville, NC.  Comparative evaluation of natural and trawling sediment disturbance via short-lived radionuclides, in situ monitors and remote sensing techniques in the Pamlico River Estuary, North Carolina.

Seabed disturbance by bottom trawling has emerged as a major concern related to the conservation of essential fish habitat and water quality. Bottom sediments directly affect water quality by releasing nutrients when freshly deposited organic matter is remineralized.  Resuspension and subsequent transport of bottom sediments disturbed by natural physical mixing (e.g. wind) of overlying waters or anthropogenic interactions (i.e. trawling) results in the advective release of dissolved constituents (NH4, NO3-NO2, PO4) from interstitial waters into overlying surface waters.  Our study attempts to delineate natural resuspension and transport of surface sediments from trawling disturbances in South Creek, a shallow tributary of the Pamilco River, North Carolina.  Our study site encompasses two similar areas, both containing a trawled and untrawled region (~100,000 m² per region).  Within each region, concentrations of total suspended solids, dissolved nutrients and surface sediment inventories of ²³⁴Th and ⁷Be were quantified several days before and after a controlled trawling event.  In addition, meteorological information (wind speed, direction, etc.) was collected in close proximity to the study site.  Our first set of experiments, July and October 2001, suggest that trawling plays a minor role in sediment resuspension relative to natural wind events.  Work to be conducted during summer 2002 will incorporate satellite imagery (AVHRR SeaWiFS) and in situ monitoring devices (current velocity, CTD, turbidity) to further constrain the importance of natural vs. trawling induced resuspension.  We hope our techniques will provide the basis for operational monitoring, and provide 'real-time' information to resource managers.

FREEMAN, S. M. (s.m.freeman@cefas.co.uk)* and S.I. Rogers; CEFAS, Lowestoft Laboratory, Lowestoft, Suffolk, United Kingdom.  The sensitivity of fish and macro-epifauna to habitat change: an analytical approach.

Increased use of seabed resources and greater awareness of the effects of fishing on the seabed call for an urgent need to assess the extent and diversity of seabed habitats affected by such activities. Existing methods that describe and predict the distribution of benthic habitats using either substrata or depth are generally inadequate. When other factors such as tidal velocity, temperature and salinity are combined with substrata and depth, they more clearly characterize these habitats. Principal components analysis (PCA) was used to evaluate the distribution and abundance of fish and macro-epifauna using a suite of factors. Characteristic habitat types were identified and provided a mechanism for predicting their spatial extent. A new analytical approach to link species to their habitat was constructed using a combination of PCA and a generalized additive model (GAM). The method predicts the habitat preferences of an individual species based on their association with the environment. Preferences were used to describe the likelihood of a species occurring across a range of different habitats; this was called the habitat-envelope.  The strength of the association between species patchiness and its habitat-envelope indicated the potential sensitivity of the species to habitat change. Generally, fish had larger habitat-envelopes and more likely to exploit a wider range of habitats than crustaceans, whereas echinoderms were more selective, and hence more sensitive to habitat change.

FREESE, J. L. (linc.freese@noaa.gov); NOAA National Marine Fisheries Service, Auke Bay Laboratory, Juneau, AK.  Impacts of mobile fishing gear on sponges and gorgonian corals in the Gulf of Alaska.

Research carried out in deep water on the continental shelf in the eastern Gulf of Alaska (GOA) has shown that gorgonian corals and erect sponges provide significant components of the complex habitat in that area.  These organisms are susceptible to impacts by mobile fishing gear, and are slow to recover from damage once disturbed.  This poster presents an overview of these studies, and also presents results of surveys from a submersible vehicle aimed at identifying and characterizing sites that may be deemed Habitat Areas of Particular Concern.

FOGARTY, M.J. (Michael.Fogarty@noaa.gov); National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Woods Hole, MA.  Approaches to minimizing impacts of fishing activities on benthic habitats.

The need to consider the direct and indirect effects of fishing activities on the productivity of marine populations, communities, and ecosystems is now widely appreciated.  Fishery management strategies have traditionally centered on controlling the direct effects of harvesting on the productivity of exploited stocks.  The recognition of the need to consider the broader ecosystem effects of fishing has focused attention on management strategies designed also to preserve vulnerable habitats, conserve biodiversity, and protect ecosystem goods and services.  Management approaches developed to address these considerations include (a) the use of various forms of spatial management strategies and (b) constraints on gear design and/or fishing practices. Marine protected areas of various forms, including no-take marine reserves, extension of traditional fishery closure strategies, and rotational management strategies have now been broadly implemented with the objective of meeting ecosystem-based management goals.  Gear design considerations include the use of structural modifications to minimize adverse impacts on habitat.  Changes in fishing practices to minimize habitat contact and resulting damage have also been developed . Here, the experience with management approaches for protecting vulnerable fishery habitats is reviewed with particular emphasis on the use of marine protected areas and on gear-design solutions to habitat impact problems.  The vulnerability of different habitats to fishing impacts is a function of inter-related factors such as the natural rates of disturbance, structural complexity, and  community composition.  The potential efficacy of alternative solutions based on spatial management and/or gear design approaches is evaluated in this context.

FRID C.L.J. (c.l.j.frid@ncl.ac.uk), L.A. ROBINSON and J.BREMNER; Dove Marine Laboratory, Department of Marine Science & Coastal Management, University of Newcastle upon Tyne, Cullercoats, North Shields, United Kingdom.  Muddy thinking: ecosystem based management of marine benthos.

Globally a number of states/parties are developing ecosystem-based approaches to environmental management. For the North Sea, OSPAR and North Sea Conference initiatives have identified a number of metrics for possible use in 'managing the benthos'. Against this background we consider the fixation of some parties with complex indices the behaviour of which are poorly linked to human actions and are not readily amenable to management measures. We argue that the development of this framework needs to recognize that it is impacting activities which can be managed and that science should concentrate on the development of both robust Decision Support ('Performance') metrics and Environmental State ('Descriptive') metrics in order to inform this management. A number of case studies are used to illustrate the strengths and failings of some the proposed metrics. Performance' metrics should be linked closely to the impacting activity.  Thus changes in the metric can immediately trigger a management response. We consider various proposed metrics and comment on their utility in the context of managing fisheries effects. Descriptive metrics, such as diversity indices, are useful for identifying patterns in community structure and assessing the potential consequences of impacts. However, they do not directly link changes to particular activities, making it difficult to assign causality and so apply management. To date much of the focus of these considerations has been on taxonomic based measures. We go on to consider the metrics that can also be developed to assess the functioning of the ecosystem.

FRID, C.L.J. (c.l.j.frid@ncl.ac.uk)*¹, C.L. SCOTT¹, M.F. BORGES², N. DAAN⁴, T.S. GRAY¹, J. HATCHARD¹, L. HILL², O.A.L. PARAMOR¹, G.J. PIET⁴, S.A. RAGNARSSON³, W. SILVERT², L. TAYLOR³;  ¹University of Newcastle, Newcastle upon Tyne, England, ²Instituto Portugês de Investigação das Pescas e do Mar, Lisboa, Portugal, ³Marine Research Institute, Reykjavik, Iceland, ⁴Netherlands Institutes for Fisheries Research, IJmuiden, The Netherlands.  Developing a fisheries ecosystem plan for the North Sea.

Considerable effort is being directed in many countries towards achieving sustainable exploitation of fisheries resources, protection of the ecosystem, safeguarding biological diversity and the promotion of sustainable fishing industries. Fisheries Ecosystem Plans (FEPs) are seen as one way of delivering these simultaneous management objectives while matching to the biological realities of the underpinning resources. In January 2002 the European Union commissioned an innovative project to marry together socio-economic theory with ecological understanding of the marine systems under study. The first phase in the process has been the development and initiation of links with the stakeholders to obtain their opinions on their preferred management regimes. The second phase is the characterisation of the biological and physical-chemical environment of the North Sea, which supports the fishery, leading to the development of a conceptual model of the North Sea food web. This is intended to supply a FEP for the North Sea which is acceptable to the stakeholders balanced with achieving protection of the ecosystem. In this poster we present the initial results that indicate that combinations of models can evaluate the ecological consequences of alternative management strategies and the interaction of different sets of fishes with varying life history characteristics. Preliminary data from the stakeholders has been both aggregated (to obtain an overall preference ranking of all stakeholders) and disaggregated (to identify the preference rankings of particular countries and different sectors of stakeholders). The stakeholders appear to appreciate the effort to factor in their preferences into the construction of a FEP and are open to further discussion in this ongoing project.

GAGE, J.D. (jdg@dml.ac.uk)*¹, J.M. ROBERTS¹, J. HUMPHERY², and P.A. LAMONT¹;  ¹Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, UK, ²Proudman Oceanographic Laboratory, Bidston Observatory, Birkenhead United Kingdom.  Deep-sea trawling impacts on the benthic ecosystem along the northern European continental margin.

Although historical overfishing and sustained bottom trawling and dredging has deeply imprinted the benthic ecology of fine sediments of inshore waters worldwide, the deep-sea environment beyond the continental shelf edge has remained a pristine wilderness until quite recently.  Deep-sea trawling off northern Europe has developed rapidly over the past two decade from exploration to targeted, and now probably overexploited, fisheries.  Large, but slow-growing, sessile seabed invertebrates, such as glass sponges and cold-water coral, are well developed but regarded as nuisance to fishers who have even deliberately damaged or destroyed cold-water coral reefs in order to enhance a short-term fish catch.  Yet no targeted studies of impacts on the benthic ecosystem have yet been funded by the European Union despite mounting evidence for collateral damage from dragging heavy rockhopper trawls over the seabed causing direct physical damage and smothering by sediment resuspension, while the high level of discarded bycatch has an unknown impact on benthic food chains. This paper reviews evidence of physical impacts on the seabed obtained mainly from seabed photography along the continental slope off Scotland where trawling  to depths in excess of 1,500 m.  We categorise and interpret scattered and incomplete data, including evidence of damage to seabed organisms, and discuss relationships to sediment type and trawl-mark longevity.  We also present evidence from box-core sampling on the Hebridean continental slope for change in macrobenthic community composition since the 1970s, predating the development of the deep-sea fishery.

GARDNER, J. V. (jvgardner@usgs.gov)*¹ and L. A. MAYER²;  ¹U.S. Geological Survey, Menlo Park, CA, ²University of New Hampshire, Durham, NH.  Benthic habitat mapping with advanced technologies and their application.

Today's ability to map the seafloor was unheard of two decades ago.  Navigational accuracies, as well as spatial and elevation resolutions have now reached the decimeter scale.  But are today's resolutions fine enough for biologists trying to characterize specific benthic habitats?  Do biologists know what resolutions are necessary to define their benthic habitat of interest?  Once biologists have high-resolution data, do they have the technologies to visualize and analyze their newly acquired data?  Do Agencies have the budgets required to use 21st century technology? High-resolution seafloor mapping technologies come in a variety of flavors with a variety of resolutions, from airborne lidar to underwater photography.  Each system has it's own pros and cons relative to the particular goal of the seafloor mapper.  For instance, a living platform coral reef can be efficiently mapped with an airborne lidar but the spatial resolution is 2 m x 2 m, at best, with a depth resolution of a few centimeters.  The data are spectacular, albeit costly.  But are these resolutions good enough to characterize the platform coral reef habitat for biological or management purposes?  If not, then maybe underwater video/still photography is required.  Underwater video/still photography is very labor intensive to acquire and process into useful imagery.  Although the spatial resolution can be millimeter-scale, there is poor vertical resolution unless stereo photography is collected.  And, to map an entire platform coral reef with underwater video or still photography would be an enormous undertakingÑmeaning expensive. Examples of several seafloor-mapping techniques will be shown and their pros and cons will be discussed.

GAUVIN, J.R. (gauvin@seanet.com); Groundfish Forum, Inc.  Approaches to EFH management for Alaska groundfish fisheries that fulfill habitat management objectives and maintain viable groundfish fisheries.

While there are still many unknowns and contradictory evidence regarding the effects of on-bottom trawling on benthic habitat and fish populations, there is relatively more agreement among scientists and some stakeholders regarding the need to enact additional measures to manage trawling on hard bottom substrates, particularly those inhabited by concentrations of long-lived and vulnerable invertebrates such as sponges and corals.  This is particularly true where these fragile and sessile epifauna occur in waters too deep to be appreciably affected by natural disturbance, and thus where benthic animals and structure would not be expected to be adapted to disturbance events.  My paper will present a set of what I believe are non-traditional approaches to management of trawl effects in deep water areas.  These alternative measures are designed to meet habitat protection objectives of the M-S Act while allowing the other mandates of the Act to be attained as well.  My paper will focus on the hard bottom fisheries off Alaska where, I believe, a set of conditions exist that allow for more flexible approaches to management of trawl fisheries.  Fishery managers and stakeholders in Alaska are currently reviewing existing protections for EFH in the context of the court ruling that NMFS had failed to meet NEPA requirements in its earlier analysis of management options for EFH.  Some members of the fishing industry in Alaska are interested in consideration of an alternative set of measures from the simplistic time/area closures.  We believe that additional sweeping closures could actually compress and intensify fishing effects, possibly triggering a negative outcome for the areas left open to fishing.  Hence an alternative approach merits consideration.  It is hoped that at least some of the alternatives presented in my paper will have been accepted for analysis in the Environmental Impact Statement currently being developed for our region by the time of Symposium.

Gilkinson, K.D. (gilkinsonk@dfo-mpo.gc.ca)*¹, D.C. Gordon Jr.², G.B. Fader³, D.L. McKeown², E.L.R Kenchington², D. Roddick², C. Bourbonnais², K. MacIsaac², and W.P. Vass²; ¹ Department of Fisheries and Oceans, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland, Canada, ² Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada, ³ Natural Resources Canada, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada.  Impacts of hydraulic clam dredging on benthic macrofaunal communities and physical habitat on Banquereau, a fishing bank off Nova Scotia.

Although hydraulic clam dredging has been conducted in eastern Canadian offshore waters since the mid-1980's little is known about the associated environmental impacts. In 1998, a joint clamming industry-government dredging impact experiment was initiated on a sandy seabed on Banquereau (Scotian Shelf) at water depths of 70-80 m. Incorporated into the experimental design were commercial fishing practices including pulse dredging followed by a fallow period.  Both immediate and longer-term physical and biological impacts were examined using a variety of acoustic, video/still photography, and direct sampling gears.  Seabed topography, which was dramatically altered by dredging, returned to near normal conditions two years after dredging, although dredge tracks remained visible in sidescan sonograms. There was evidence that large increases in numbers of brittlestars over the two-year post-dredging period may represent active dredging-induced immigration and retention over large areas. Dredging significantly reduced the abundance and biomass of a large number of species, although most polychaetes and amphipods had returned to or exceeded pre-dredging levels one year after dredging.  Biomass of the target bivalve species, Arctic surfclam (Mactromeris polynyma) and northern propellerclam (Cyrtodaria siliqua), was greatly reduced (by approximately 50%) and recovery is not expected for at least 10 years.  The ecological significance of changes in abundance and biomass of the macrofaunal community (270 taxa), particularly large ecosystem engineers which through their burrow structures and empty shells shape habitat structure, is a key area of research in this fishery which, by its nature, removes benthic biomass while attracting re-colonization by opportunists.

GILLELAN, H. (hannah@mcbi.org)*¹, with MARINE CONSERVATION BIOLOGY INSTITUTE¹ and OCEANA²;  ¹Marine Conservation Biology Institute, Arlington, VA, ²Oceana, Washington, DC.  The Ocean Habitat Protection Act: overdue protection for structurally complex seafloor habitats.

Until the mid-1980s, bottom trawls were used only on relatively flat ocean bottoms where the net would not snag on vertical structures such as corals, boulders, shipwrecks, and rock pinnacles.  Large, heavy roller and rockhopper gear now enables bottom trawls to access areas of the oceans that were previously safe havens for marine life and fragile habitats.  There is increasing scientific consensus that trawling in structurally complex habitats is one of the most destructive types of bottom fishing because of the long-term damage it causes to the diversity, species abundance, and ecological processes dependent on these habitats.  Commercially and recreationally important fish, such as rockfish, haddock, Atlantic cod, snappers/groupers, and American lobster, and other types of marine life depend on structurally complex habitat during different stages of their lives.  The young of species can show far greater survival rates where the seabed is complex.  Where bottom structure has been damaged by bottom trawlers, diversity and the health of fish populations are negatively impacted.  The Ocean Habitat Protection Act, by limiting roller and rockhopper gear to an 8-inch diameter, would protect these essential, structurally complex habitats by removing the gear that allows access to the habitats.  Many states and several federal Fishery Management Councils have passed regulations that have begun to address this threat by restricting use of this gear in designated areas or fisheries.  However, the patchwork of existing regulations often applies only to certain fisheries and leaves unprotected large areas of sensitive deep-sea corals, sponge beds, and other aggregations of geologic and biogenic structures.  The restriction proposed by this bill is one shown to have been effective at reducing trawling in these habitats on the West Coast.  Implementation of this gear restriction would maintain biodiversity and healthy seafloor habitats, and would assist many depleted species in recovery to sustainable levels.

GLEASON, A.C.R. (art.gleason@miami.edu)*¹, A.-M. EKLUND², R.P. REID¹, D.E. HARPER², D.B. MCCLELLAN², and J. SCHULL²;  ¹Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, ²National Marine Fisheries Service, Southeast Fisheries Science Center, Miami, FL.  Integration of acoustic seabed classification and fish census data for determining appropriate boundaries of marine protected areas.

In southern Florida, fine-scale benthic habitat maps are unavailable for water depths greater than 20 m because the depth is too great to effectively exploit traditional optical mapping methods. These deep water zones may, however, harbor diverse communities of benthic invertebrates and fish that are under-represented in most population surveys. In the Florida Keys, for example, SCUBA divers documented black grouper aggregations at 28 m depth, just seaward of a no-take zone within the Florida Keys National Marine Sanctuary, but the distribution of potential deep-water grouper spawning habitats in the Florida Keys is as yet unknown. Systematic mapping of the acoustic diversity of the sea floor (i.e. variations in response of diverse bottom types to an acoustic signal) offers a potential means for (1) identifying deep-water benthic habitats, (2) describing relationships between benthos and substrate on a regional scale, and (3) establishing effective boundaries of marine protected areas. We are currently using the sea bed classification system QTC VIEW system V to map bottom types in the vicinity of Carysfort reef, a known site of black grouper (Mycteroperca bonaci) aggregation. The acoustic mapping is being performed in coordination with diver-based surveys of fish populations. Mapping results guide the locations of dives, which are limited in time and scope due to water depth. Diver surveys, in turn, provide ground truth data to refine and adjust classification maps. Delimiting benthic habitats that are potential sites of grouper aggregation is critical to defining appropriate boundaries of marine reserves.

GODINEZ-DOMINGUEZ, E. (egodinez@mail2.udc.es)*^1,2, J. FREIRE², G. GONZÁLEZ-SANSÓN³;  ¹ Centro de Ecologia Costera, Universidad de Guadalajara, Jalisco. México, ² Departamento de Biologia Animal, Biologia Vegetal y Ecologia, Universidad de A Coruña, A Coruña, España, ³Centro de Investigaciones Marinas, Universidad de la Habana, La Habana, Cuba.  Fishing and environmental disturbance indicators in a shrimp fishing ground at the Mexican central Pacific.

This paper examines the concurrent effects induced by trawl shrimp fisheries, natural seasonal dynamics and interannual processes as ENSO events on a soft bottom macroinvertebrate community. Short-term effects were evaluated during an initial period of two years when five trawl cruises were carried out in successive closed and open fishing seasons coinciding with the main hydroclimatic periods. In each cruise seven sites along 100 km of coastline were selected and four depths were sampled (20, 40, 60 and 80 m). A series of community structural descriptors used frequently to determine the ecological effects of fishing disturbances were employed: ABC curves, W-statistic, normalized species size distribution as biomass spectra, spatial segregation index, Shannon diversity index, species richness and biomass.  Inter-annual effects were analysed with data from semi-monthly cruises in 2 sites and the same four depths from 1995 to 1998. Theoretical predictions of the effects of fishing in the behaviour of the statistical indices used were tested. Results show a strong evidence that fishing has produced a state of chronic disturbance in the macroinvertebrate community. Short-term fishing effects could be masked by natural seasonal and interannual environmental changes. Results of short-term effects are not in agreement with the fishing disturbance theories. The trends found could evidence interannual effects associated to El Ni-o and La Ni-a events. The complexity of the sources of variability in a exploited community forces managers to adopt a more widely adaptive approach which should be focused on understanding the community structural process through temporal and spatial gradients, and to use several structural indices to evaluate critically their performance as indicators of fishing disturbance.

GORDON, D.C. JR. (gordond@mar.dfo-mpo.gc.ca)*¹, K.D. GILKINSON², E.L.R. KENCHINGTON¹, J. PRENA¹, C. BOURBONNAIS¹ K.G. MACISAAC¹, D.L. MCKEOWN¹ and W.P. VASS¹;  ¹Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada, ²Department of Fisheries and Oceans, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland, Canada.  Summary of the Grand Banks otter trawling experiment (1993-1995): effects on a sandy bottom habitat and community.

A large scale, three-year experiment was conducted to examine the effects of repetitive otter trawling (twelve sets once a year) on a species-rich (over 250 taxa), sandy bottom ecosystem (120-146 m) on the Grand Banks of Newfoundland that had not been fished for over ten years.  A wide variety of equipment (e.g. sidescan, video platform, epibenthic sled, videograb) was used to collect data from replicate trawled and reference corridors (13 km long). Immediate physical effects on habitat were observed but the available evidence suggests that the habitat recovered in about a year or less.  Except for snow crabs and basket stars, direct removal of epibenthic species by the otter trawl was insignificant.  Immediately after trawling, the mean biomass of epibenthic organisms was reduced by 24%.  The most affected epibenthic species were snow crabs, basket stars, sand dollars, brittle stars, sea urchins and soft corals.  Both the immediate and medium-term impacts on the resident benthic infauna appeared to be minor.  Significant effects could not be detected on the majority of species found at the study site, including all the molluscs.  All available evidence suggests that the biological community recovered from the annual trawling disturbance in less than a year, and no significant effect could be seen on benthic community structure after three years of otter trawling.  The habitat and biological community at the experimental site are naturally dynamic and exhibited marked changes irrespective of trawling activity, and this natural variability appeared to over-shadow the effects of trawling.

GRIMES, C. B. ¹, M. YOKLAVICH¹, W. WAKEFIELD², and H. G. GREENE³;  ¹National Marine Fisheries Service, Southwest Fisheries Science Center, Santa Cruz Laboratory, Santa Cruz, CA ²National Marine Fisheries Service, Northwest Fisheries Science Center, Newport, OR, ³Moss Landing Marine Laboratories, Moss Landing, CA. Using lasers to investigate deepwater habitats in the Monterey Bay National Marine Sanctuary off central California.

We conducted a 9-day field test of laser line-scan imaging technology (LLS) to investigate benthic marine habitats in and around the Big Creek Ecological Reserve (BCER) off the central California coast. We determined the utility of LLS for determining the distribution and abundance of fish and megafaunal invertebrates, and identifying habitats and species associations by comparing LLS images with those acquired from side-scan sonar and a remotely-operated vehicle. We also evaluated the ability of LLS to detect seafloor disturbance caused by fishing trawl gear. We surveyed a 2.6 km long x 0.4 km wide area  inside and directly outside BCER. With the laser we imaged isolated  rock outcrops with patches of large Metridium sp., dense schools of fishes, drift kelp, sea pens, salp chains, and sedentary benthic fishes (possibly California halibut, Pacific electric ray, ratfish and juvenile lingcod.). The LLS system offers the advantage of imaging both the biogenic and abiotic components of habitat, and depicts their spatial relationships with detail that currently is not possible using acoustic imaging techniques such as side-scan and multibeam sonar. LLS imagery also provided fine detail of low relief shelf geology such as sand waves and ripples; evaluating these features in a broader context from a post-processed mosaic of the study area could help us understand coastal physical processes that influence dynamic benthic habitats.

GRIZZLE, R. E. (ray.grizzle@unh.edu)*, L. G. WARD and J. R. ADAMS; Jackson Estuarine Laboratory, University of New Hampshire, Durham, NH. Mapping and characterizing subtidal oyster reefs using GIS and underwater videography.

Populations of the eastern oyster (Crassostrea virginica) have been in long-term decline in many areas due to over harvesting, disease, and other factors.  A major hindrance to effective oyster management has been lack of a methodology for accurately and economically obtaining data on distribution and abundance.  Here we describe a mapping protocol using GIS and underwater videography that can complement acoustics, dredging, quadrat sampling and other techniques, thereby enhancing the overall effectiveness of monitoring programs.  Videography was conducted by systematically imaging multiple sampling cells in a grid covering the approximate areas of three study reefs.  A single drop was made in each cell and a 5 to 10-s recording made of a 0.25 m² area; the location of each image was determined using differential GPS.  A still image was produced for each of the cells and all were combined into a single photomontage overlaid onto a geo-referenced basemap for each reef using ArcView GIS.  Comparisons of the video data to single beam and multibeam acoustic maps and quadrat data from the same study reefs suggest: (1) acoustics and systematic videography can readily delimit the boundaries of oyster reefs; (2) systematic videography can provide spatially detailed information on shell densities and reef structure useful in guiding sampling by dredges, quadrats and other destructive techniques; and (3) some combination of acoustics, systematic videography, and destructive sampling can enhance the level of information on oyster reef characteristics typically available to managers.

GROSSMAN, E.E.* (egrossman@usgs.gov), M.E. FIELD, and S.L. EITTREIM; U.S. Geological Survey, Pacific Science Center, Santa Cruz, CA.  Geologic development and longevity of continental shelf mudbelt habitat during the Holocene in the Monterey Bay National Marine Sanctuary, California.

Recent degradation of benthic habitat and fish stocks is related to both anthropogenic and natural causes. Subsurface geological investigations augment seafloor and habitat mapping to provide constraints on habitat development, longevity, and variability due to natural geophysical processes. A principal geologic feature of the Monterey Bay National Marine Sanctuary is a 421 km² mudbelt that extends across a vast proportion of the continental shelf and reaches a maximum thickness of ~32 m.  Basal ¹⁴C ages of ~14 ka indicate the mudbelt is Holocene and ²¹⁰Pb accumulation rates show it is presently accreting at 0.24-0.39 cm/yr.  Lithologic variations within cores show that the accumulation of this deposit occurred episodically under significantly different depositional energy. Seismic reflection profiles show that mudbelt development on the underlying fossil terrace was governed by complex interactions between fine sediment input (primarily from three major rivers) and transport (cross-shelf and along-shelf) during the Holocene sea-level transgression. Lateral variability in accumulation would have profound impacts on surrounding habitats as muds and sands were partitioned and deposited where they exist today. The composition and age of sediment within mudbelt cores help to define the nature of seabed sediment through time, its longevity as potential essential fish habitat, and its vulnerability to forces acting on the seafloor. Understanding the evolution and rates of sediment transport and accumulation of this and similar mudbelts that occur within important and threatened groundfish habitat along most modern coasts will provide a context for interpreting modern changes to essential fish habitat.

GUIDA, V.G. (vincent.guida@noaa.gov)*¹, P.C. VALENTINE², and F. ALMEIDA³;  ¹National Marine Fisheries Service, Northeast Fisheries Science Center, Highlands, NJ, ²U.S. Geological Survey, Woods Hole Field Center, Woods Hole, MA, ³National Marine Fisheries Service, Northeast Fisheries Science Center, Woods Hole, MA.  Effects of fishing on the mid-Atlantic tilefish habitat: restructuring a structured habitat.

The tilefish habitat on the New Jersey continental shelf and uppermost slope near Hudson Canyon is a little studied, heavily trawled region (~800 km²) with unusual sediments and topography and substantial fisheries habitat value.  During October 2001, we conducted an investigation to map the distribution of habitat types, macrofaunal associations and trawling disturbance at depths of 100-300 m.  Side scan sonar was used for mapping and locating stations for video transects, using the SEABOSS drift camera vehicle, and for sediment grab sampling.  Otter trawl tows were made to assess abundances and confirm the identities of organisms seen on video.  Surficial sediments consisting of sand-clay mixtures, underlain by consolidated clay and producing high side scan backscatter, occurred at depths exceeding 111 m.  The combination of sidescan sonar and visual observations revealed the structural complexity of the habitat.  Low relief structures included hummocks, biogenic depressions, trawl marks, tilefish burrows, small burrows (1-6 cm diameter), and linear strings of cobbles and boulders. Trawl mark frequencies ranged from 100% coverage to complete absence. Benthic megafauna seen in videos at all stations (sea pens: Virgularia sp., sea stars: Astropecten americanus, cerianthid anemones, brachyuran crabs) showed no pattern with respect to trawl disturbance. Fish, e.g. spotted hake (Urophycis regius), were commonly seen in depressions.  Areas with trawl marks had fewer depressions, small burrows, hummocks, and fewer fish than comparable ones without such marks, suggesting a negative impact on habitat value by bottom trawls.  The cobble/boulder habitat supported the greatest density and diversity of fishes.

GUIDA, V.G. (vincent.guida@noaa.gov)*¹, A. PAULSON¹, P.C. VALENTINE², and L. ARLEN¹;  ¹National Marine Fisheries Service, Northeast Fisheries Science Center, Highlands, NJ, ²U.S. Geological Survey, Woods Hole Field Center, Woods Hole, MA.  Effects of fishing on organic carbon content of sand habitats on Georges Bank.

A 4.5 year closure to fishing of an area on Georges Bank provided an opportunity to compare physical and chemical characteristics of sand habitats from areas that had not been subjected to fishing with adjacent areas that had been fished. Sediment cores (6-15 cm deep) taken by Van Veen grab sampler in June 1999 were sectioned into 1 cm depth segments and analyzed for Total Organic Carbon (TOC, particulate plus interstitial), and for grain size.  Grain size was the most important factor influencing TOC, which correlated positively with mud content.  Where similar grain size distributions occurred at nearby stations inside the area closed to fishing and outside, TOC values were significantly higher in the upper sediment layers of inside (unfished) stations.   Comparing TOC between inside-outside station pairs with similar grain sizes revealed two distinct patterns, suggesting two distinct mechanisms for TOC depletion.  In the first, TOC of the upper 2 cm of the fished station was depleted compared to the unfished station.  This probably reflects advection of depositional organic matter upon resuspension by fishing.  In the second pattern, the sediment column from the fished station was depleted in TOC relative to unfished sediments to a depth of 5 cm or more.  This pattern may reflect an overall increase in remineralization resulting from vertical redistribution of labile organic substrates and oxidants from the surface by fishing turbation.  Which mechanism predominates may depend upon bottom hydrology, the rate and composition of organic matter deposition, and the texture and dynamics of the sediments.

HART, T.D. (hartt@ucs.orst.edu)* and S.S. HEPPELL; Oregon State University, Department of Fish and Wildlife, Corvallis, OR. An assessment of fish and invertebrate communities along trans-Pacific cable lines: a pilot study with implications for marine reserve planning.

Marine protected areas are currently being considered along the Oregon coast with the intention of rebuilding stocks.  But stakeholders have questioned the effectiveness of reserves and little data exist with regard to marine reserves or the effects of fishing activities on benthic habitat along the Oregon coast.  A unique opportunity exists to begin to collect such information because of de facto no-trawl reserves that exist along submerged coastal corridors where trans-oceanic communication cables have been laid across the seafloor.  I intend to investigate a cluster of unburied cables, which extend off the Oregon coast just north of Bandon (summer, 2002).  The corridor of reduced fishing impact, according to the trawl log book data, is approximately 2 miles wide and extends out from shore approximately 14 miles to about 70 fathoms.  With the use of an ROV (remotely operated vehicle), commercial trawl data, and bathymetry data, I will be able to analyze the impact, if any, these de facto refuges have had on bottom-dwelling invertebrates and fish species of commercial importance.  Specifically, I will analyze individual groundfish species associations with different substrate types and invertebrates within and outside of the cable corridor.  This collaborative research will establish a credible baseline study on which to build further investigation regarding possible design of a successful marine reserve for groundfish and invertebrate species along the Oregon coast.

HARTOG, F. (hartogf@dfo-mpo.gc.ca)*¹, P. ARCHAMBAULT¹, L. FORTIER2;  ¹Institut Maurice Lamontagne, Ministère des Pêches et des Océans, Mont-Joli, Québec, Canada, 2Département de biologie, Université Laval, Ste-Foy, Québec, Canada. Impacts of scallop dredging on marine bottom complexity and juvenile fish habitat.

Dredging for scallops is known to reduce habitat complexity by homogenizing the sediments structure and by the removal of epibenthic organisms. Large bivalves such as scallops and their shells provide secondary substrate and physical structure adding to the complexity of the bottom. A complex habitat may enhance survival and growth of juvenile fishes by providing refuges from predation, abundance of prey and shelters from water flow. The Magdalen Islands shelf, in the Gulf of Saint-Lawrence, supports a fishery for Giant scallops (Placopecten magelanicus) and is believed to be a nursery area for juvenile Atlantic cod (Gadus morhua). Four scallop beds are still fished while three have been closed to fishing for 4, 10 and 12 years. During the summer 2002, three locations closed to dredging will be compared to three dredged locations in order to detect fishing impacts on epifauna and fish habitat. Bottom complexity and epifauna diversity and species abundances will be assessed from photographic sampling. Demersal fishes associated with the bottom will be sampled with fine mesh experimental nets. A complexity index will integrate sediment features, biogenic structures and patchiness values. Hypotheses are that unfished locations will be more complex and that juvenile fish and emergent benthic species will be more diverse and abundant at these locations. Epifauna diversity, abundances and assemblages will also be compared from fish and unfished sites. Differences in epifauna and fish assemblages will be examined.

HE, P. (Pingguo.He@unh.edu); University of New Hampshire, Durham, NH. Reducing seabed contact of bottom trawls.

Typical bottom trawls leave tracks when they are towed over the seabed due to trawl doors and bobbins, or other roller gears in contact with the seabed.  Reducing contacting points of doors or bobbins can reduce tracks left by trawls and impact of trawling on benthic system.  Footgear or sweep of a bottom trawl may consist large steel bobbins in order to roll over rough grounds to protect netting from damaging.  We examined if the number of bobbins on an offshore shrimp trawl was necessary for maintaining trawl geometry and stability, and preventing the gear from damaging when fishing for shrimps off Newfoundland and Labrador.  Through flume tank tests, we were able to balance a commercial shrimp trawl when the number of bobbins was reduced from the original 31 to nine.  Reducing the number of bobbins on the footgear also reduced drag of the trawl by 12%, resulting in savings on fuel. Preliminary sea trials indicated that the trawl with less number of bobbins on its footgear may result in the footgear intermittently being lifted off bottom, but this may not necessarily result in reduction in catch of shrimps.  The trawl rigged with less bobbins on its footgear was more likely to incur damage when fishing under rough sea and seabed conditions. We are continuing the project in Newfoundland and in New England with the concept of semi-pelagic shrimp trawls with either trawl doors off the seabed while leaving the trawl on the bottom, or with the bottom-contacting trawl doors and a off-bottom "sweepless" trawl.

HEIFETZ, J. (jon.heifetz@noaa.gov)*¹, D.L. Courtney¹, J.T. Fujioka¹, H.G. Greene², P.Malecha¹, and R.P. Stone¹;  ¹National Marine Fisheries Service, Auke Bay Lab, Juneau, AK, ²Moss Landing Marine Lab, Moss Landing, CA.  Benthic habitat in the Gulf of Alaska: biological communities, geological habitat, and fishing intensity.

Multibeam, backscatter, and video data were collected on Portlock Bank near Kodiak, Alaska in the vicinity of groundfish fisheries. The objective was to characterize habitat in heavily fished grounds to understand whether habitats in current fishing grounds are vulnerable to ongoing fishing activities. The multibeam and backscatter data indicated at least a dozen macro- or meso-habitats.  The megahabitats are the result of past glaciation and are presently being reworked into moderate (cm-m) relief features. Submarine canyons notch the upper slope and provide steep relief with alternating mud-covered and consolidated sediment exposures.   The video data from the submersible Delta, indicated little evidence of trawling on the low relief grounds of the continental shelf where perhaps the level bottom did not induce door gouging and there was a lack of boulders to be turned over or dragged. The most common epifauna were crinoids, small non-burrowing sea anemones, glass sponges, stylasterid corals and brittlestars.  Occasional large boulders were located in depressions were the only anomaly in the otherwise flat seafloor.  These depressions may have afforded some protection to fishing gear, as the glass sponges and stylasterid corals attached to these boulders were larger than were typically observed.  In contrast, there was evidence of boulders turned over or dragged by trawling in the areas of the upper slope. The uneven bottom perhaps induced gouging by the trawl doors. The substrate was mostly small boulders, cobble, and gravel.  Presently there does not appear to be much habitat in this area that can be damaged by trawling. No large corals and very few large sponges were seen.  Whether this is the result of past trawl activity is unclear.

HENRY, L.M. (lhenry@is2.dal.ca); Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada. Community and life history divergence of colonial hydroids (Cnidaria, Hydrozoa) from heavily trawled scallop grounds in the Bay of Fundy, eastern Canada.

Adverse effects of mobile bottom-fishing gear on communities of colonial invertebrates  (sponges, anthozoans, hydrozoans and bryozoans) are rarely examined, and no studies have determined if sub-lethal damage caused by this gear impairs the life histories (e.g., sexual reproduction, growth competitive ability) of these animals. Colonial hydroids were used as a model group to investigate these issues at the community, population and colony-levels from heavily fished scallop grounds in the Bay of Fundy, eastern Canada. An MDS ordination of hydroid communities collected from the shells of 109 live scallops (Placopecten magellanicus) and 136 small boulders revealed a moderately strong divergence between these two assemblages: epilithic communities were comprised of more runner and vine-shaped annual species, while epizoic taxa typically had more arborescent morphologies with perennial lifespans. RAPD-PCR genetic techniques of 414 colonies revealed that epilithic populations of the upright macrobenthic hydroid Sertularia cupressina were dominated by fewer genotypes than those on live scallops. Epilithic colonies were damaged more often, less abundant, less often fertile and comprised of fewer, smaller and less fecund modular units than those on epizoic substrates. Field and lab experiments are planned to test the hypothesis that higher incidences of damage to colonies on small boulders versus live scallops explain community and life history divergence between epilithic and epizoic assemblages. The implications of divergent communities and impaired sexual reproduction will be discussed to emphasize the importance of considering 'less obvious' effects of bottom-fishing on marine benthos.

HERNÁNDEZ-DELGADO, E.A. (coral_giac@yahoo.com)*, and A.M. SABAT; University of Puerto Rico, Department of Biology, Coral Reef Research Group, San Juan, PR.  Rapid build-up of fish biomass, but still declining coral reefs: Why a marine fishery reserve designation is not enough for the protection of reef epibenthic communities?

Reef fish communities in Culebra Island (27 km off northeastern Puerto Rico) have declined significantly in recent years.  In 1999 the government of Puerto Rico established the Luis Pe-a Channel Marine Fishery Reserve (LPCMFR) with the objective of restoring local fisheries.  Random stationary visual censuses and permanent line intercept transects have been used since 1996 to document the long-term changes in the coral reef fish and epibenthic communities assemblages before and after designation.  A preliminary comparison of data from 1999 and 2002 shows a 38% increase in mean fish species richness/census.  A dramatic increase in the abundance (2,539%)  and in the biomass 26,618% of the yellowtail snapper, Ocyurus chrysurus, was observed.  Also, a significant increase in the abundance (414%)  and in the biomass (868%) of the schoolmaster, Lutjanus apodus, was documented.  In spite of that, a significant decline of epibenthic communities was observed between 1997 and 2001, including coral species richness (31%), colony abundance (24%), and % coral cover (39%).  Also, a 175% mean increase in macroalgal cover was documented.  This decline was attributed to a combination of long-term indirect cascade effects of spearfishing, low densities of Diadema antillarum, and to coral disease outbreaks.  These results suggest that although a MFR can be an excellent management tool to restore depleted fish stocks, the recovery fish communities alone is not enough to prevent further coral reefs decline associated to acute severe mortality caused by disease.  Active restoration, in combination with MFRs, is recommended to recover coral reef epibenthic communities.

HILL, R.L. (ron.hill@noaa.gov)*¹, P. F. SHERIDAN¹, R.S. APPELDOORN², T.R. MATTHEWS³, and K.R. UWATE⁴;  ¹NOAA National Marine Fisheries Service, Southeast Fisheries Science Center, Galveston, TX, ²Department of Marine Sciences, University of Puerto Rico-Mayagüez, Lajas, PR, ³FWC Florida Marine Research Institute, Marathon, FL, ⁴Division of Fish and Wildlife, U.S. Virgin Islands Department of Planning and Natural Resources, St. Thomas, VI.  Analyzing the effects of trap fishing in coral reef habitats: methods and preliminary results.

Trap fishing is common near coral reefs in Florida and the U.S. Caribbean but little is known about the effects of these stationary gears on targeted habitats.  This cooperative study between NOAA Fisheries, local resource agencies, academic researchers, and the fishing industry is investigating the effects of traps on coral reef and reef-associated habitats in the Florida Keys (lobster and stone crab traps) and in Puerto Rico and the U.S. Virgin Islands (fish and lobster traps).  The initial stages of the project are underway; they include: 1) mapping the distribution of traps, 2) quantifying trap densities by habitat, and 3) quantifying damage to corals and other structural organisms.  Preliminary findings from the Caribbean suggest that a relatively small percentage (<20%) of the traps set in shallow water (< 30 m) actually contact hard corals, gorgonians, or sponges. In these limited findings, damage occurred mainly to hard corals and was patchy, at a scale less than the total trap foot print.  Continued research will assess whether these preliminary findings are representative of coast-wide trap fisheries and will provide more precise data on trap fishing intensity by habitat type, seasonal movement of traps among habitats, and potential for gear impacts to associated habitat components such as seagrasses, macroalgae, and sponges.  A better understanding of how trap fishing affects essential fish habitats like coral reefs is integral to the development of sustainable fisheries and improved resource management.

Hinz, H. (h.hinz@bangor.ac.uk)*¹, M.J. Kaiser¹, M. Bergmann¹, and S.I. Rogers²;  ¹School of Ocean Science, University of Wales-Bangor, Anglesey, United Kingdom, ²The Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory, Lowestoft, Suffolk, United Kingdom.  Using ideal free distribution theory to identify potential marine protected areas.

There is increasing interest in the use of marine protected areas (MPAs) as tools to achieve the goal of ecosystem management. MPAs could counteract these effects by limiting the impact on areas important for feeding, shelter, spawning and migration. Thus MPAs should include features that enable fish to reach maturity and thus contribute to the spawning stock. But how do we find the most suitable habitats for fish species in large marine areas? Ecological theory (ideal free distribution) suggests that fish will be most abundant in areas that have the most favourable habitat characteristics for that species. Fish stock assessment data could be used to assess where fish species consistently tend to aggregate. In this study we examined stock assessment data collected for three flatfish species (plaice, sole and lemon sole) from 134 stations in the English Channel over nine years. Juvenile fish were excluded from the analysis. The fish abundance data for each year was ranked and the mean rank calculated. The coefficient of variation of the mean rank score had the least variability at stations with the highest mean rank scores and also at those with the lowest rank scores. Stations that had a mid-range mean rank had the greatest inter-annual variation. It would appear that stations with the highest mean rank abundance consistently attract fish.  Such areas may be the prime focus for potential MPAs

HOOGE, P. N. (philip_hooge@usgs.gov)*¹, P.R. CARLSON², and G.R. COCHRAN²;  ¹U.S. Geological Survey, Gustavus, AK, ²U.S. Geological Survey, Menlo Park, CA.  Effects of ice gouging on community structure and the abundance of Pacific halibut (Hippoglossus stenolepis):  disturbance does not necessarily mean negative fisheries effects.

Sidescan sonar and multibeam imagery of Glacier Bay, Alaska revealed complex iceberg gouge patterns at water depths to 135 m on the floor of Whidbey Passage and south to the Bay's entrance.  These previously undiscovered gouges formed >100 yrs ago, as the Little Ice Age glacier retreated rapidly up Glacier Bay.  Gouged areas supported greater biodiversity than nearby ungouged areas or sediment-filled gouges, probably due to increased habitat complexity.  Small Pacific halibut (Hippoglossus stenolepis) were found more frequently in gouged areas, presumably due to higher prey abundance.  These results contrast with the disturbance effects of recent, shallow ice gouging on community composition observed in the Arctic.

HUBER, D. (dorthea@gbrmpa.gov.au); Great Barrier Reef Marine Park Authority, Fisheries Issues Group, Townsville, Queensland, Australia.  The path towards ecologically sustainable fisheries: a case study in the Great Barrier Reef World Heritage area.

Australia's Great Barrier Reef is the largest complex of reefs and islands in the world and it supports the most diverse ecosystem known to man. As a result of its unique status the Great Barrier Reef was included on the World Heritage List in 1981.  The Great Barrier Reef Marine Park Authority (GBRMPA) is responsible for managing this vast and complex ecosystem in accordance with World Heritage values.  The Authority must manage and conserve this unique system for future generations, whilst providing reasonable multi-use access to tourism, traditional hunting by indigenous people, recreational, charter and commercial fishing. Achievement of these goals requires a multi-jurisdictional, multi-sectoral and multi-agency approach.  Trawling, line fishing and netting are the major forms of commercial fishing activity within the Marine Park.  There are also smaller trap and harvest fisheries. All commercial fishing activity is managed by the Australian State of Queensland on a day-to-day basis. However, in line with its broader mandate to ensure the maintenance of World Heritage values, the Authority has a co-management role for commercial fisheries in the Marine Park.  To achieve this the GBRMPA uses Zoning Plans, Management Plans, permits, regulations and education.  Members of the Authority are also represented on various State based Management Advisory Committees. Of all commercial fishing in the World Heritage Area, trawling for prawns and scallops has the biggest impact on the benthic environment. Some 550 vessels have access to nearly 172,000 km² of Marine Park.  The fishery has undergone a major and highly controversial restructure in the past two years. Amongst the achievements was a significant reduction and capping of fishing effort, the closure of an additional 96,000 km² of Marine Park, the mandatory use of turtle excluder devices and bycatch reduction devices throughout the park, restrictions on the targeting of species and the use of a Vessel Monitoring System whilst trawling.  The trawl fishery of the Great Barrier Reef World Heritage Area has still a long way to go to achieve ecological sustainability but concessions won over the past two years present a major step along this path.

IAMPIETRO, P. and R. KVITEK (rikk_kvitek@csumb.edu)*; California State University Monterey Bay, ESSP, Seafloor Mapping Lab, Seaside, CA.  Quantitative seafloor habitat classification using GIS terrain analysis: effects of data density, resolution, and scale.

There is a great need for accurate, comprehensive maps of seafloor habitat for use in fish stock assessment, marine protected area design, and other resource management pursuits. Recent advances in acoustic remote sensing technology have made it possible to obtain high-resolution (meter to sub-meter) digital elevation models (DEMs) of seafloor bathymetry that can rival or surpass those available for the terrestrial environment. This study attempts to use an algorithmic terrain analysis approach to efficiently, non-subjectively classify seafloor habitats according to quantifiable parameters such as slope, rugosity, and topographic position index (TPI). In addition, we explore the effects of original x,y,z and gridded data density on the results of these analyses, in order to provide insight into how inherent depth-dependent decreases in data density may affect this approach, and to assess the appropriateness of using historical, lower density bathymetric data. Finally, issues of scale with regard to rugosity and TPI are explored and their potential biological relevance discussed.

JAY, C.V. (chad_jay@usgs.gov)*¹, L.C. HUFF², and R.A. MCCONNAUGHEY³;  ¹U.S. Geological Survey, Alaska Science Center, Anchorage, AK, ²NOAA-University of New Hampshire, Joint Hydrographic Center, Chase Ocean Engineering Lab, Durham, NH, ³National Marine Fisheries Service, Alaska Fisheries Science Center, Seattle, WA.  Benthic perturbations from walrus foraging: are they similar to trawling?

The Pacific walrus roots through soft sediment and feeds on a wide variety of benthic organisms, and in the process, they resuspend sediment and disturb much of the fauna in their path.  Some of the consequences of walrus foraging may be similar to those produced from bottom trawling.  In a preliminary study, we are using side-scan sonar images to identify walrus foraging tracks (furrows) in soft sediments to measure the distribution of foraging patches and the level of foraging effort of walruses in an area within Bristol Bay, Alaska.  The approximate area affected and level of mechanical disturbance to the sea floor from walrus foraging are contrasted to those that might be expected to be produced from bottom trawling.

JENNINGS, S. (S.Jennings@cefas.co.uk)* and S.M. FREEMAN; CEFAS, Lowestoft Laboratory, Lowestoft, United Kingdom.  Ecosystem consequences of fishing effects on benthic habitat.

Fishing has direct and indirect effects on benthic habitats. We review these effects and discuss appropriate methods for mapping and classifying them across a range of spatial and temporal scales. Subsequently, we suggest approaches for assessing the consequences of fishing-induced habitat modification on populations, communities and ecosystems, with emphasis on the production and biomass of populations, the diversity of communities and functional processes in ecosystems. For populations, communities and ecosystems, we describe a range fisheries and environmental management objectives, and ask how the impacts of fishing on habitat will compromise them. We show that perceptions of the significance of fishing effects on benthic habitat are strongly influenced by the scale of analysis and the perceived objectives of management. A rational strategy for mitigating the undesirable effects of fishing on benthic habitat will require a-priori agreement on management objectives.

KAISER, M. J. (m.j.kaiser@bangor.ac.uk); School of Ocean Sciences, University of Wales-Bangor, Anglesey, United Kingdom. Detecting the effects of fishing on seabed community diversity: importance of scale and sample size.

I investigated the importance of the extent of area sampled to the observed outcome of comparisons of the diversity of seabed assemblages in different areas of the seabed that experience either low or high levels of fishing disturbance. Using a finite data set, within each disturbance regime, samples of the benthic communities were pooled at random. Thus while individual sample size increased with each additional level of pooled data, the number of samples decreased accordingly. Detecting the effects of disturbance on species diversity was strongly scale dependent. Despite increased replication at smaller scales, disturbance effects were more apparent when larger, but less numerous, samples were collected. The detection of disturbance effects was also affected by the choice of sampling device. Disturbance effects were apparent when using pooled anchor-dredge samples, but were not apparent for pooled beam-trawl samples. A more detailed examination of the beam-trawl data emphasised that a whole community approach to the investigation of changes in diversity can miss responses in particular components (e.g. decapod crustacea) of the community. The latter may be more adversely affected by disturbance in comparison with the majority of the taxa found within the benthic assemblage. Further, the diversity of some groups (e.g. echinoderms) actually increased with disturbance. Experimental designs and sampling regimes that focus on diversity at only one scale may miss important disturbance effects that occur at larger or smaller scales.

KELLER, B.D. (brian.keller@noaa.gov); Florida Keys National Marine Sanctuary, Marathon, FL. Monitoring changes in the fully protected zones of the Florida Keys National Marine Sanctuary.

The Florida Keys National Marine Sanctuary is a 9,850 km2 marine protected area managed by the U.S. National Oceanic and Atmospheric Administration and the State of Florida.  A comprehensive management plan was implemented in 1997 to protect and conserve marine resources of the Florida Keys.  One aspect of the management plan is the creation of a network of 24 fully protected zones (marine reserves). An ongoing monitoring program is designed to determine effects of 'no-take' protection on heavily exploited fishes and invertebrates, benthic communities, and human activities.  Data on the abundance and size of fish, spiny lobster, and queen conch; algal cover, diversity and recruitment; and zone usage are collected from fully protected zones and adjacent reference sites.  Preliminary results indicate increases within fully protected zones in the number and size of heavily exploited species such as spiny lobster and certain reef fishes.  Slower growing benthic species such as corals and sponges have not shown significant changes with fully protected zones, possibly because the zoning plan was implemented less than five years ago.

KELLERT, S. R. (stephen.kellert@yale.edu); Tweedy Ordway Professor of Social Ecology, Yale University School of Forestry and Environmental Studies, New Haven, CT.  The role of human values, perceptions, and ethics of the marine environment.

This presentation will argue that beyond good science, management technology, and regulatory policies, the effective and sustainable management of fishing activities in benthic habitats over the long-term will depend on people developing an ethic toward the marine environment based on a greatly expanded understanding of human self-interest.  This ethic will be based on the recognition of how much human physical and mental well-being relies on a diverse array of values and benefits of the marine environment.  Conversely, this ethic will depend on the realization that the degradation of the marine environment inevitably reduces human physical, material, emotional, intellectual, and spiritual capacity.  This ethic of enlightened self-interest, thus, relies on far more than a narrow material and economic calculus, including as well a notion of utility that emphasizes the human dependence on the marine environment for human creativity and problem solving, cognitive and affective capacity, moral and spiritual relation, and more.  This perspective treats the human dependence on the marine environment as rooted in human biology, and how during the course of our species evolution people came to rely on the marine realm as a source of adaptive benefits essential in the struggle to survive and thrive as individuals and collectivities.  This human genetic affinity for nature and the sea is referred to as 'biophilia.'  The notion of biophilia is linked to nine biologically based values that will be described, and when adaptively expressed support an ethic of stewardship for the marine environment.  These nine values and their relation to an ethic toward the sea are viewed, however, as 'weak' biological tendencies, requiring adequate experience, learning, and social support to become adaptively expressed.  Finally, an illustration will be provided of radically altered values and ethical perspectives of large cetaceans during this century, indicative of how rapidly and profoundly an ethic toward aspects of the marine environment can develop under particular circumstances.

KENCHINGTON, E.L.R. (kenchingtone@mar.dfo-mpo.gc.ca)*¹, K.D. GILKINSON², GORDON, D.C. JR.¹, C. BOURBONNAIS¹, K.G. MACISAAC¹, D.L. MCKEOWN¹, G.B. Fader³, and W.P. VASS¹;  ¹Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada, ²Department of Fisheries and Oceans, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland, Canada, ³ Natural Resources Canada, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada.  Impacts of otter trawling on the gravel habitat of Western Bank, Nova Scotia.

The impact of repetitive otter trawling on a low relief gravel habitat (70 m) was studied for three years (1997-1999) at an undisturbed 2 x 2 km experimental site within the Scotian Shelf 4TVW haddock nursery area, which has been closed to groundfish fisheries since 1987. The experimental design was an asymmetrical BACI with one trawled corridor and three reference corridors.  Each year, twelve trawl sets were made with an Engel 145 rockhopper otter trawl. Eighteen species of demersal fish were captured in the trawl with biomass increasing after the first set.  This is indicative of scavenging behaviour and supported by an increase in stomach weight with successive sets.  Detailed analysis of the stomach content of selected species showed changes in diet associated with trawling.  For example, Atlantic cod (Gadus morhua) had increased consumption of the horse mussel (Modiolus modiolus) and the terebellid polychaete (Thelepus cincinnatus) after the first set.  Benthic surveying before and after otter trawling each year included sidescan sonar, video, photography and sampling by videograb.  Trawl door marks were immediately evident in sonograms and still detectable a year later.  Signs of disturbance and damage were visible in video and photography, but not as frequent as expected.  The most abundant benthic species were the amphipod (Ericthonius fasciatus) and the polychaete (Chone duneri).  Biomass was dominated by M. modiolus and T.  cincinnatus.  The most frequently sampled benthic organisms were M. modiolus, polychaetes, and ophiuroids.  The immediate and medium-term (i.e. 3 years) impacts of repetitive trawling on this gravel benthic community will be discussed.

KENNEDY, G.W. (gregory_kennedy@usgs.gov)*¹, M.C. FABRIZIO², M.A. BLOUIN¹, and J.F. SAVINO¹; ¹ U.S. Geological Survey, Great Lakes Science Center, Ann Arbor, MI, ² NOAA Fisheries, Northeast Fisheries Science Center, James J. Howard Marine Sciences Laboratory, Highlands, NJ.  Sampling macrozoobenthos from zebra mussel communities in Lake Erie.

Macrozoobenthos found on hard substrate areas in central Lake Erie were examined as part of a larger study to understand the use of nearshore areas by larval and juvenile fishes.  Large portions of nearshore habitats were colonized in the 1990's by dreissenid mussels, Dreissena polymorphya (zebra mussel) and Dreissena bugensis (quagga mussel), which makes standard sampling methods for benthos largely ineffective.  To provide quantitative collection of macrozoobenthic organisms inhabiting these hard substrate areas, we developed a method involving the use of SCUBA and underwater suction sampling.  One-quarter m² quadrats were sampled using a submersible suction sampler to collect free-ranging macrozoobenthos, followed by collection of dreissenid mussels within the quadrat immediately afterward.  Comparisons were made of the benthos collected by suction with the benthos remaining among the mussels to determine the effectiveness of the suction sampling method.  Preliminary estimates show that over 90% of the total number of organisms and over 95% of the total taxa in each 0.25 m² area were collected by suction sampling.  Relationships between the benthos taxa and the dreissenid mussels and density of mussel populations are currently being examined.  These data are critical for determining the relationship and linkages between juvenile fishes and invertebrate prey found in these altered Great Lakes habitats.

KOENIG, C.C. (koenig@bio.fsu.edu)*¹, A.N. SHEPARD², J. REED³, R.G. GILMORE⁴, F.C. COLEMAN¹, S. BROOKE³, J. BRUSHER⁵, M. BARNETTE⁶, A.W. DAVID⁵, and K. SCANLON⁷;  ¹Department of Biological Science, Florida State University, Tallahassee, FL, ²National Undersea Research Program, University of North Carolina at Wilmington, Wilmington, NC, ³Harbor Branch Oceanographic Institute, Fort Pierce, FL, ⁴Dynamac Corp., Kennedy Space Center, FL, ⁵National Marine Fisheries Service, Panama City, FL, ⁶National Marine Fisheries Service, Southeast Regional Office, St. Petersburg, FL, ⁷U.S. Geological Survey, Woods Hole, MA.  Florida Oculina coral banks: habitat, fish populations, restoration, and enforcement.

The shelf-edge Oculina coral reef ecosystem off Florida's east coast exists nowhere else on earth.  The branching coral heads coalesce into thickets supporting high biodiversity and high densities of economically important reef fish. The South Atlantic Fishery Management Council in 1984 declared 92 nmi² an HAPC, ostensibly protecting it from trawling and other disruptive activities.  In 1994, the Council, moved by evidence of dramatic sex-ratio shifts in grouper populations, closed the HAPC to bottom fishing for 10 years to test the effect of closures on grouper reproductive capacity, and in 2001 expanded the HAPC to 300 nmi².  In 1995, we found the habitat and the reeffish populations dramatically reduced from historical (1970s) levels.  Our more recent habitat mapping and characterization (2001) found 90% of the Oculina habitat within the reserve reduced to rubble.  To our knowledge, only about 8 hectares of intact thicket remain.  We started Oculina restoration in 2000, based on demonstrated high transplant survival rates.  Results indicate that restoration structures simulating Oculina reefs attract reef fish and may provide spawning habitat.  Although current video characterization methods are not directly comparable to 1995 methods, they are quantitative, showing: increased grouper density, size, and male abundance, suggesting recovery; and the appearance of juvenile speckled hind, suggesting a nursery function.  Evidence is very strong that shrimpers continue illegal trawling within the HAPC.  The Council proposed new management measures to stop trawling within the HAPC.  The HAPC habitat is being characterized and mapped.

KOSTYLEV, V.E. (Vladimir.Kostylev@NRCan.gc.ca)*¹, B.J. TODD¹, O. LONGVA², and P.C. VALENTINE³;  ¹Geological Survey of Canada (Atlantic), Dartmouth,  Nova Scotia, Canada, ²Geological Survey of Norway, Trondheim, Norway, ³U.S. Geological Survey, Woods Hole, MA.  Characterization of benthic habitat on eastern Georges Bank.

Georges Bank management issues are the focus of scientific and public attention in Canada and the United States. On the species-rich gravel habitats of northern Georges Bank, fishing gear impact (scallop dredging) results in habitat degradation and deterioration. Multibeam bathymetry data from the Canadian portion of Georges Bank reveal the complexity of seabed morphology and give insight into geological processes that occur there. Bathymetric and backscatter maps, sidescan sonograms, seismic reflection records and sea floor sediment grab samples were interpreted to produce a map of surficial geology. Underwater digital video, photography and grab samples were used to describe benthic communities and the distribution of species occurring in various habitats. Evidence suggests that Georges Bank was not overridden by glacial ice and was subaerial at the end of the last glacial period. Wave and current action during post-glacial sea-level transgression reworked Georges Bank sediment, building the complex pattern of bedforms observed today. Mobile sand dominates on the shallowest part of the bank but gravel is a major component on the remainder of the bank. The sand comprises sheets and sand wave fields with a maximum sand wave height of 18 m. Bedform morphology and video observations suggest that the sea floor on the bank is a dynamic sedimentary environment where gravel habitats may be buried by bedload transport initiated by tidal and storm wave currents. This habitat instability is reflected in life history traits of benthic species and necessitates an evaluation of the relative importance of natural and fishery-related disturbances.

KOULOURI, P. (yo172@imbc.gr)*¹, C. DOUNAS¹, and A. ELEFTHERIOU²;  ¹Institute of Marine Biology of Crete, ²University of Crete.  Preliminary results on the effect of otter trawling on hyperbenthic communities in Heraklion Bay (Eastern Mediterranean, Cretan Sea).

Although the fauna occupying the water layer adjacent to the ocean floor has been focused for commercial exploitation, little attention has been paid to the study of the small invertebrates inhabiting the same biotope referred to as the hyperbenthos. Recently, there has been an increased interest in this faunal group as many demersal fish and epibenthic crustaceans are found to feed on it, for at least part of their life. Otter trawls, the most common gear used for demersal fishing, result in significant disturbance of the sediment-water interface. Consequently, animals that are disturbed due to the passage of a trawl may become sources of food for predators and scavengers. The impacts of towed fishing gears and especially of otter trawling on hyperbenthos have not been studied at all. In order to study the effect of otter trawling on hyperbenthos in the continental shelf of Heraklion Bay, a method simulating otter trawl groundrope conduct with the seabed was applied. A modified three-level hyperbenthic sledge was used for collecting disturbed (groundrope present) and undisturbed (without groundrope) macrofaunal samples at a towing speed normally used by the commercial vessels. Comparison of the results from both disturbed and undisturbed samples revealed significant differences indicating that the groundrope disturbs the hyperbenthic community in such a severe degree that it probably increases the vulnerability of these animals to their predators. This potential impact could lead to additional changes in habitat complexity and community structure of the shelf ecosystem.

KULKA, D.W. (Kulkad@dfo-mpo.gc.ca)*¹. and D.A. PITCHER²;  ¹Department of Fisheries and Oceans, St. John's, Newfoundland, Canada, ²Spatial Metrics Atlantic, Dartmouth,  Nova Scotia, Canada. Spatial and temporal patterns in trawling activity in the Canadian Atlantic and Pacific.

GIS was used to spatially analyze trawling in Canadian Atlantic and Pacific waters as part of a program to assess the effect of trawling on benthic habitats. Data for 1980-2000 (Atlantic) and 1994-2000 (Pacific) in the form of geo-referenced fishing set locations were used to spatially describe effort location. The results are a series of maps depicting the spatial distribution of trawling intensity. Temporal changes and patterns in trawling intensity are described. In the Atlantic, trawl grounds are patchy and complex covering between 8 and 38% of the shelf in any year although actual trawled bottom area is much smaller. Spatial patterns of trawling changed dramatically over the time sequence analyzed but locations of high intensity trawling were similar from one year to the next. The spatial patterns were most stable during the 1980's while the greatest changes occurred during the early 1990's. There were numerous persistent areas of trawling spread mainly along the shelf edge and between the banks. A substantial portion (shallow and shoreward) of the shelf was consistently un-fished. In the Pacific, the trawl locations were more consistent but the observed timeframe was much shorter (1994-2000). Trawl grounds comprised a string of partially joined patches along the shelf edge off Vancouver Island, three patches within the southern Queen Charlotte Sound, south and east of Queen Charlotte Island at deeper locations and on the shelf edge north and west of Queen Charlotte Island. The results, a first step in quantifying trawl effects, provide precise information on extent and intensity of bottom disturbance due to trawling.

KUTTI, T. (oddb@imr.no)*¹, T. HØISÆTER¹, H.T. RAPP¹, O.B. HUMBORSTAD², S. LØKKEBORG², and L. NØTTESTAD²;  ¹Institute of Fisheries and Marine Biology, University of Bergen, Norway, ² Fish Capture Division, Institute of Marine Research, Bergen, Norway.  Immediate effects of experimental otter trawling on the benthic assemblage of Bear Island (fishery protection zone), Barents Sea.

The immediate effects of intensive experimental otter trawling on marine benthic fauna and assemblages was assessed in a gravely arctic benthic ecosystem at ~100 m depth. The research site was located within the Fishery Protection Zone around Bear Island, Barents Sea. To quantify the effects of trawl-disturbance a BACI design (Before and After/Control and Impact) was adopted. Replicate samples were collected using a Sneli epibenthic sledge, equipped with video camera and ITI positioning system to enable estimation of the area sampled. The benthic assemblage was characterised by a small-scale patchy distribution of fauna. The samples were numerically dominated by ophiuroids, polychaetes, bivalves, cirripeds and echinoids while echinoids and cirripeds dominated the biomass of the assemblage. Trawling affected the benthic assemblage mainly through resuspension of surface sediment and through a relocation of shallow burrowing infaunal species to the surface of the seafloor. Immediately after trawling we found a significant increase in the abundance of a majority of the infaunal bivalves, some common burrowing gastropods and anthozoans. We also observed a significant increase in the biomass of ophiuroids that could be a result of scavenging behaviour. The total biomass (mainly cirripeds) was reduced whereas diversity, based on biomass data, was significantly higher after trawling. Due to a large inter sample variance, effects of trawling were difficult to assess on individual species. However, a significant decline in the number of some amphipods, mysides and euphausides was observed. Multivariate analyses further indicated that trawling had a homogenising effect on the benthic assemblage.

LANE*, G. C. (mlatrips@cmaquarium.org); Clearwater Marine Aquarium, Clearwater FL.  Building a database for benthic fisheries using tourist income.

Tourist dollars and programming can be utilized for real science. The Marine Life Adventures Program at the Clearwater Marine Aquarium has been developing programs and curriculums that both teach hands-on science and help contribute to the building of a database of juvenile fisheries in the Clearwater Harbor (St Joseph's Sound) area of western Florida. To date, they have cataloged nearly 150 species in a program that samples benthic habitats twice a day almost every day of the year. At present, there are nearly 100 sample sites that cover the entire range of benthic habitats found in the Harbor. These sites range from a depth of 1.2 to 5.0 meters. The most amazing thing is that all this is cheerfully paid for by tourist dollars and produces a product that is scientifically sound and has been utilized by Universities, Planners, and local governments. We believe that it is the first program of it's kind in the world, and can be a model for cash-strapped and budget hungry institutions to help offset some of the costs of obtaining this type of data.

LARSEN, L.-H. (LHL@akvaplan.niva.no)*¹, A. ZENETOS² and N. STREFTARIS²;  ¹Akvaplan-niva, The Polar Environmental Centre, Tromso, Norway, ²National Centre for Marine Research, Athens, Greece. Identification and evaluation of indicators for environmental performance of European marine fisheries.

Fishing activities are known to have significant effects not only on target species, but also on the wider marine environment. This is a result of the incidental catch of non-target species, and physical disturbance of benthic habitats and communities from bottom fishing gear. Indirect effects of forced ecosystem changes are also known from intensive fishing areas.  The Central Fisheries Policy (CFP) of the European Union, implemented some twenty years ago, is now facing a major challenge because its contribution to sustainable, environmental performance within European marine fisheries is not well defined or explained. A scoping study has been undertaken for the identification of environmental performance indicators for the fisheries in the greater European (EU + EFTA) waters. Of the 23 indicators, two are directly relevant to fishing and benthic habitat concerns. These are 'Loss of fishing gear' and 'Physical damage to habitats and species'. The report compiles results on habitat and species alterations from more than 100 individual national and European wide research projects on the interactions between fisheries and the environment. These studies collectively resulted in more than 1000 individual scientific publications.  The methodology of the scoping study is presented, including criteria for selection of indicators. The data compilation on one indicator 'physical damage to habitats and species' and other indicators relevant to this symposium are described and illustrated. Examples of habitat alterations are given from European (North Sea benthic trawling) and Arctic (Barents Sea shrimp trawling) fisheries and implications for management practice and the CFP are presented.

LINDEBOOM, H.J. (H.J.Lindeboom@Alterra.wag-ur.nl); Netherlands Institute for Sea Research (NIOZ)/ALTERRA, Texel, The Netherlands.  Comparison of effects of fishing with effects of natural events and non-fishing anthropogenic impacts on benthic habitats.

Fishing with bottom towed gears leads to the destruction of habitat types such as shellfish and seagrass beds, coral reefs and maerl grounds, and to shifts in species composition and age structure of benthic populations and communities. Natural events and other anthropogenic impacts can lead to similar effects.  As far as natural variability is concerned, when combining data series on algae, macrofauna and the breeding success of birds, it is striking that certain changes are very sudden and not gradual, as one would expect, for example, from gradual increasing human impact. The doubling of algal biomass in the Dutch coastal zone between 1976 and 1978, followed by the macrobenthos in 1980, and coinciding with an increase in the Eider duck breeding success by several orders of magnitude all hint to sudden changes or 'shifts' in the marine ecosystem. These types of changes can also be observed in many other data series. Other major shifts occurred in the North Sea in the late 1980s, while classic examples took place in the 1930s and 1890s. Domain and regime shifts have also been reported for the North Pacific, even in open ocean waters.  Many longer data series indicate interannual and decadal changes among which the following phenomena may be observed: sudden rapid changes, gradual changes (e.g. in the direction of trends), changes in (seasonal) variability, changes in dominance of species and cyclic variations.  What causes these phenomena? The patterns that we see are the result of a very complex interplay between many forcings with local or global characteristics. Weather patterns, reflected in El Ni-o or the North Atlantic Oscillation, cold winters, warm summers, storms, ocean currents, solar activity, lunar tidal cycles, and human impacts such as fisheries, eutrophication, pollution and dike building, and biological features such as population dynamics and the intrinsic capability of ecosystems to shift, all add to the extremely complex and sometimes chaotic picture that we observe.  These complex mixtures of causes will be presented for several case studies. In 1883, oysterbeds covered more than 20,000 km2 of the eastern North Sea floor. A combination of changing hydrography, overfishing and possibly diseases rapidly diminished these beds, and since the 1960s none are left. Although one may argue that hydrographical shifts were a major cause of the local extinction, the present day heavy beam trawl fisheries make the return of oysters to this area very unlikely.  Antifouling paint causes imposex in whelks, leading to very low numbers of these animals along the major shipping routes in the North Sea. However, detailed research indicated that fisheries are taking a much higher toll than TBT.   Eutrophication may lead to increased algal biomasses and more macrofauna. In that case, it may counteract effects of fisheries. However, excess eutrophication causes anoxia and the death of many benthic organisms.  The effects of fisheries and other causes of changes in the ecosystem will be compared with these and other examples. Arguments that non-linearity and extreme complexity hamper a good understanding of the phenomena observed, as well as predicting the effects of managerial measures, will be presented.

LINDHOLM, J.B. (james.lindholm@noaa.gov)*^1,2, P.J. AUSTER¹, and P. VALENTINE³;  ¹National Undersea Research Center at the University of Connecticut, Groton, CT, ²NOAA's Stellwagen Bank National Marine Sanctuary, Scituate, MA, ³US Geological Survey, Woods Hole, MA. A comparison of habitat structure in fished and un-fished, mobile and immobile sand habitats on Georges Bank (Northwest Atlantic).

Fishing has been described as the dominant anthropogenic impact to marine ecosystems worldwide. One subset of impacts is caused by fishing with mobile bottom-contact gear (e.g., scallop dredges, bottom trawls) on seafloor habitat and associated taxa.  Mobile fishing gear reduces seafloor habitat complexity through the removal of emergent fauna that provide structure (e.g., erect sponges), the removal of structure-building megafauna that produce pits and burrows (e.g., crabs, fish), and the smoothing of bedforms (e.g., sand waves).  In this study we compared the relative abundance of microhabitat features (the scale at which individual fish associate with seafloor habitat) inside and outside of a large closed area on Georges Bank (closed in December 1994 and sampled in June 1999).  A total of 32 stations were selected in a paired sampling design inside and outside of the closed area in sand habitats. Video and still photographic transects were conducted at each station using the Seabed Observation and Sampling System.  Seven common (i.e., flat sand, rippled sand, sand with emergent fauna, bare gravel, gravel with emergent fauna, shell, shell fragment) and two 'rare' (sponges, biogenic depressions) microhabitat types were compared separately.  Analyses were conducted for 'mobile sand' habitats (< 60 meters water depth) and for 'immobile sand' habitats (> 60 meters). Results showed no significant differences in the relative abundance of the common microhabitat types between fished and unfished areas in mobile or immobile sand habitats.  However, in immobile sand habitats sponges and biogenic depressions were numerically more abundant inside the closed area.

LINK, J. (jlink@whsun1.wh.whoi.edu)*¹, F. ALMEIDA¹, R. REID², P. VALENTINE³, L. ARLEN², V. GUIDA², D. PACKER², T. NOJI², and J. VITALIANO²;  ¹National Marine Fisheries Service, Northeast Fisheries Science Center, Woods Hole, MA, ²National Marine Fisheries Service, Northeast Fisheries Science Center, Highlands, NJ, ³U.S. Geological Survey, Woods Hole Field Center, Woods Hole, MA.  The effectiveness of marine protected areas on fish and benthic fauna: how long does it take for benthic habitat to recover from fishing disturbance?

In late 1994, a substantial portion of Georges Bank was closed to commercial fishing (Closed Areas I, II, and the Nantucket Lightship Closed Area) to assist with stock rebuilding.  After four or five years of closure, all three closed areas exhibited a notable increase in biomass and density of sea scallops, Placopecten magellanicus, and were subsequently reopened to the scallop fishery.  At various points in time before, during, and after the industry was allowed entry into these areas, we conducted surveys to monitor the status of benthic habitat and fauna inside the three closed areas.  Sites were selected to sample locations that were undredged since the closure, that were dredged after four years of closure, and five years after closure.  In addition, some sites were sampled <10 days, six months, or one year after dredging. At each station, we conducted video transects, collected still photos, CTD casts, and sediment samples for physical and chemical analysis.  A Smith-McIntyre bottom sampler was then used to sample the benthic community, followed by an otter trawl.  Trawl catches were sorted to species and all fish and invertebrates were weighed, enumerated, and measured.  Stomach contents, maturity observations, and age structures were collected for selected species at each station.  Results suggest a notable sequence of 'recovery' in terms of habitat and biotic metrics.  We conclude that the recovery time of an area is highly dependant upon the substrate type, representing a gradient from relatively rapid recovery on sandy bottoms and cobble and boulder bottoms taking notably longer.  The differences in recovery times we observed for the different bottom types can have significant implications on plans of future area closures for fisheries management in this region and other regions around the world.

LOCKHART, D. (Doug.Lockhart@thales-geosolutions.com)*, R.J. PAWLOWSKI, and E. SAADE; Thales GeoSolutions (Pacific), Inc., San Diego, CA.  Determining seabed characteristics through multibeam echosounder system backscatter analysis and digital terrain models.

Advances in collection and processing of backscatter data from multibeam echosounder survey technology is providing information on seabed habitat that previously had only been available through comparison of echosounder and sidescan sonar surveys or from direct visual surveys.  Through collection of backcatter data, in conjunction with routine multibeam echosounder data collection, a co-registered data set is built that can be used to classify seabed types. A backscatter data set is derived through analysis of the reflectance signal strength, on a beam-by-beam basis, across the swath of the multibeam echosounder survey.  Backscatter data can be processed into psuedosidescan seabed mosaics that depict bottom hardness and sediment characteristics.  Mosaics are compared with seabed digital terrain models to characterize seabed structure and marine habitats to a new level of detail and accuracy.   With this approach, quantitative precisely geo-referenced psuedosidescan imagery from automated processing is replacing qualitative labor-intensive sidescan imagery positioned in a quasi-accurate geo-referenced system.  This approach allows increased data collection rates with improved signal processing and leads to increased area coverage per allocated mulitibeam system.   Because of the quantitative and precise geo-referenced data set, the collection and processing can be used to develop substrate baselines and lead to quantifying change over periods of time for marine habitats. This technology is commercially exportable, with the processing tools and techniques for backscatter analysis are described.  Examples of recent habitat characterization in Alaska are provided.

LOZANO, S.J. (Stephen.lozano@noaa.gov)*¹, M. Blouin², and N. Wattrus³;  ¹NOAA, Oceanic and Atmospheric Research, Great Lakes Environmental Research Laboratory, ²U.S. Geological Survey, ³University of Minnesota. Characterization of coastal Great Lakes benthic habitat.

Colonization by dreissenid mussels, Dreissena polymorpha (Zebra) and Dreissena bugensis (Quagga), is one of the more ecologically important events to occur in the Great Lakes during the last decade.  Since their introduction into the Great Lakes, dreissenids have colonized both soft and hard substrates to depths of 80 m and reached average densities of 40,000 mussels m^-2 in the littoral zone.  Because of high densities and widespread distribution, they have modified habitats for benthos and fishes and fostered growth and proliferation of non-indigenous species, such as the round goby and a Black Sea amphipod, Echinogammarus.  In 2001, we used multibeam sonar to characterize the benthic habitat in Lake Michigan and acoustic remote sensing technology (sidescan sonar and acoustic bottom classification) to extend and extrapolate information on dreissenid distributions from spatially limited observations.  These observations were combined with discrete in situ (video and SCUBA) observations in a geographic information system (GIS). We used this system to link dreissenid distribution with substrate type, morphology and depth.  These data are critical inputs to modeling the ecological implications of dreissenid filtering on algal biomass and composition in the Great Lakes over changing environmental conditions.

MADLEY, K.A. (kevin.madley@fwc.state.fl.us); Florida Fish and Wildlife Conservation Commission, Florida Marine Research Institute, St. Petersburg, FL. A system for classification of habitats in estuarine and marine environments: Florida perspective.

A standard, benthic habitat classification system for Florida does not exist.  Over fourteen different classification systems have been used with Florida mapping projects to date.  This is problematic for efforts to compile statewide habitat area estimates, produce habitat maps for the entire state, or compare habitats across regions.  Implementation of a standardized classification system will be a large step toward more reliable characterization of Florida seafloor habitats.  The Florida Marine Research Institute has studied the classification systems used throughout Florida and the tropics and subtropics as well as successful efforts in terrestrial habitat characterization.  The goal has been to combine appropriate components of a variety of systems to form a hierarchical classification system to propose as a strawman for further testing in Florida.  We have formed this scheme with guidance from the Allee et al. 2000 NOAA Technical Memorandum for the purpose of creating a habitat characterization system compatible with the forthcoming national classification system.  The Gulf of Mexico program has interest in eventually expanding the Florida classification system to encompass habitats for all of the Gulf states.  The goal would then be to coordinate adoption of this classification system to be used by all mapping agencies involved with Gulf of Mexico habitat classification. This would enhance fishery habitat comparisons among Gulf states thus assisting fishery and habitat resource managers.

MALECHA, P.W. (pat.malecha@noaa.gov)*, R.P. STONE and J. HEIFETZ; Auke Bay Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA.  Living substrates in Alaska: distribution, abundance and species associations.

'Living substrates' have been identified as important marine habitat and are susceptible to impacts from fishing activities. In the Gulf of Alaska and Bering Sea, little is known about the distribution of deepwater living substrates such as, sponges (Phylum Porifera), sea anemones (Order Actiniaria), sea whips and sea pens (Order Pennatulacea), sea squirts (Class Ascidiacea), and ectoprocta (Phylum Bryozoa). In order to facilitate management practices that minimize fishery impacts to these living substrates, distributional maps were created based on National Marine Fisheries Service trawl survey data from 1975 through 2000. In general, the five groups of living substrates were observed along the continental shelf and upper slope in varying densities. Catch per unit effort (CPUE) of sponges was greatest along the Aleutian chain, while CPUE of sea squirts and ectoprocta was greatest in the Bering Sea. Large CPUEs of sea anemones, sea pens and sea whips were observed in both the Bering Sea and Gulf of Alaska. Species associations between living substrates and commercial fish and crab were also investigated. Flatfish were most commonly associated with sea squirts and ectoprocta; gadids with sea anemones, sea pens and sea whips; rockfish and Atka mackerel with sponges; and crab with sea anemones and sea squirts.

MATTHEWS, G.A. (geoffrey.matthews@noaa.gov)*, R.L. HILL and P.F. SHERIDAN; National Marine Fisheries Service, Galveston, TX.  A GIS routine for assessing designs that sample an area of fish or lobster traps.

Traps used in tropical fish and lobster fisheries may harm shallow reef habitats that have been identified as essential fish habitat for a number of federally managed species.  We are evaluating the effects of these traps on benthic habitats in the Florida Keys, Puerto Rico, and the U.S. Virgin Islands by examining spatial distribution of traps and quantifying damage to structural benthos.  ArcView is being used to organize and visualize the data and to choose some sampling parameters. An automated routine tests how well different transect widths represent the actual population density of traps among the area's habitats. Custom scripts register the trap population density, the trap sample density by benthic habitat, and their cumulative differences. Trap locations (latitude and longitude) and benthic habitat polygons form the bases over which the user fits a rectangle to encompass the known trap population area.  The user can then establish sub-rectangles of varying widths as 'test-transects' for sampling. A test-transect is stepped across the trap area in as many increments as desired up to a limit set by a required minimum 1-m offset distance.  The number of traps in each transect is obtained, along with the density distribution among the benthic habitats.  Using the cumulative differences in percentage distributions for habitats between test-transects and the trap population area, an optimal minimum transect width can be established to acceptably represent the distribution of traps among habitats.  This will help focus underwater research on specific habitats (corals) where damage is most likely.

MCCAY, B. (mccay@aesop.rutgers.edu); Department of Human Ecology and Center for Environmental Indicators, Cook College, Rutgers University, New Brunswick, NJ.  Fishing communities, science, and social impacts.

One major question from the "human dimension" side is whether and how the scientific basis of the question about the effects of fishing on benthic habitats can be improved.  In this regard I will briefly discuss potentials for and obstacles to greater use of fishermen's knowledge and their cooperation in carrying out research; my remarks are based on a growing literature on fishermen's knowledge as well as the recent history of cooperative research in the Mid-Atlantic and New England regions.  Among issues addressed are the very restrictive and troubled relationships evolving among government scientists, university scientists, and fishing communities and whether the increased power of environmental law suits is further marginalizing all kinds of science.  A second major question concerns the social and economic impacts of regulations on fishing activities that are intended to protect benthic habitats, whether through the Essential Fish Habitat provisions of the Magnuson-Stevens Act or through efforts to designate Marine Protected Areas for other purposes.  In this regard I will describe the GIS and survey techniques used to link closed area alternatives to fishing communities and to develop social impact analyses, based on work my team has done for the Mid-Atlantic Fishery Management Council in 2002.  Among the issues raised are the need for a far better system of routine data collection for both commercial and recreational fisheries than presently exists, the importance of including fish processing and other activities beyond harvesting in these analyses, and  problems applying the legal construct of "fishing community" to real communities.

MCCONNAUGHEY, R.A. (bob.mcconnaughey@noaa.gov)*, S.E. SYRJALA and C.B. DEW; National Marine Fisheries Service, Alaska Fisheries Science Center, Seattle, WA.  Effects of chronic bottom trawling on the size structure of soft-bottom benthic invertebrates.

Chronic bottom trawling commonly reduces benthic biomass, but it is generally unknown whether this represents a decrease in the mean size and/or the numbers of individuals.  Because this distinction provides insight into the mechanism of disturbance and also influences subsequent recovery dynamics, we investigate the matter here.  Using comprehensive historical effort data, adjacent untrawled (UT) and heavily trawled (HT) areas were identified along the boundary of a long-standing no-trawl zone in Bristol Bay, a naturally disturbed offshore area of the eastern Bering Sea. The study site is relatively shallow (44-52 m) with a sand substrate, ubiquitous bottom ripples, and strong tidal currents.  A modified research trawl was used to collect 42 HT-UT paired samples of benthic infauna and epifauna.  These data were used to compare mean sizes (kg) of 16 species of sessile, mobile and infaunal invertebrates.  15 of these taxa were smaller in the HT area, while in one case (red king crab) mean size was greater in the HT area.  Length-frequency data indicate the red king crab populations are bimodal, and that substantially fewer smaller-sized crab (rather than more larger individuals) occur in the HT area.  Since active fishing in the HT area occurred 3 or more years before our field sampling program, our findings reflect conditions associated with an intermediate stage of recovery. Finally, we compare the observed differences in mean size (attributed to heavy trawling) with natural size variability in the study area based on annual NMFS surveys.

MORTENSEN, P.B. (mortensenp@mar.dfo-mpo.gc.ca)*¹, L. BUHL-MORTENSEN¹, D.C. GORDON JR¹, G.B. Fader², D.M. MCKEOWN¹ and D.G. FENTON¹;  ¹Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada, ² Natural Resources Canada, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada.  Evidence of fisheries damage to deep-water gorgonians in the Northeast Channel between Georges and Browns Banks, Nova Scotia.

There is growing concern that fisheries and other activities on the continental shelf and slope may represent a threat to deep-water coral communities. Fishers indicate that the mouth of the Northeast Channel, the major passage into the Gulf of Maine, is an area with a high abundance of deep-water gorgonians. Because of their arborescent growth form, gorgonians are particularly susceptible to damage from fishing gear (both fixed and mobile), and recovery time is thought to be long because of their slow growth rate.  In order to minimize fishing damage to the corals, it is important to know their distribution and abundance.  During surveys of corals in the Northeast Channel with a Remotely Operated Vehicle (ROPOS) and a towed video-camera system, two gorgonian species, Paragorgia arborea and Primnoa resedaeformis, were observed between 200 and 500 m. Paragorgia and Primnoa occurred at 13 and 26 of the 38 investigated localities, respectively. The colonies grow attached to gravel (cobbles and boulders), and often have numerous associated species, both invertebrates and fish.  Signs of human impact were visible as broken live corals, scattered skeletons, and lost fishing gear entangled in corals.  Broken or tilted corals were observed at 29 % of the localities. Up to about 10 % of the corals at these sites were impacted.  The poster presents more data on spatial distribution and frequency of damaged corals, and discusses the patterns in relation to the spatial distribution of fishing activity and natural mortality of corals.

NORSE, E. (elliott@mcbi.org); Marine Conservation Biology Institute, Redmond, WA.  Destructive fishing practices and evolution of the new fishery management paradigm.

Since 1980, terrestrial natural resource managers around the world have increasingly focused on protecting, restoring and sustainably using biological diversity, the diversity of genes, species and ecosystems.  In doing so, they have increasingly taken an 'ecosystem approach' that focuses on conserving habitats of certain species and the ecosystems of which they are components for a variety of purposes ranging from use to preservation.  In contrast, natural resource managers in the sea have been and continue to focus mainly on producing meat.  They have largely overlooked the importance of biological diversity, the ecological connections among species, the importance of habitat in species conservation, and the need to protect and restore intact ecosystems as integral components of resource management. While the effects of forest clearcutting are now seen as so harmful that it has been sharply reduced in many countries, its closest marine analogues, bottom trawling and dredging, continue unabated.  There is strong suggestion that the failure to curtail destructive fishing practices has had a wide variety of adverse effects.  The period in which fishery managers have resisted modern understanding has seen sharp declines in diversity and abundance of all but the weediest, most disturbance-tolerant species. Serial depletion of targeted species, population crashes of non-targeted species, increasingly convoluted and inconsistent command-and-control regulation of fish 'stocks' and perpetual crisis in fishing communities are all signs that the prevailing fishery management paradigm is not working.  Fortunately, there are alternative ways of managing the marine realm, and the challenge the fishery management community faces is getting past its own denial and embracing new paradigms that are based on protecting, restoring and sustainably using marine biodiversity, while there is still a chance to do so.

PARKES, G.B. (graemeparkes@compuserve.com)*, H.B. LOVETT, and R.J. TRUMBLE; MRAG Americas, Inc, Tampa, FL.  Decision framework for describing and identifying EFH, mitigating fishing impacts and designating HAPC in Federal fishery management plans.

Environmental impact statements (EISs) require development of a range of reasonable alternatives for the proposed action and a comparative analysis of the environmental and economic impacts of the alternatives.  This analysis is a type of risk assessment.  In the case of designating essential fish habitat (EFH), three separate ranges of alternatives are required: those to designate EFH for each species and life stage managed by the region in question; methods to reduce or mitigate adverse fishing impacts; and alternatives for the designation of habitats of particular concern (HAPC).  A decision framework was designed to (a) facilitate the appropriate identification of alternatives for each of the three suites of actions; (b) incorporate the required criteria (per the EFH Final Rule); and (c) to frame the comparative assessment of the alternatives.  The decision framework thus incorporates the following factors.  For EFH, four levels of information:  (1) distribution data for some or all portions of the geographic range of the species; (2) habitat-related densities of the species where available; (3) growth, reproduction, or survival rates within habitats where available; and (4) production rates by habitat.  For methods to reduce or mitigate adverse fishing impacts: (1) does the fishing activity have an adverse impact; (2) is the adverse impact minimal; and (3) is the adverse impact temporary?  For designation of HAPC: (1) the ecological importance provided by the habitat; (2) the sensitivity of the habitat to human-induced environmental degradation; (3) the extent that development activities are or will be stressing the habitat; and (4) the rarity of the habitat type.

PATTERSON, W.F. (wpatterson@disl.org)*¹, C.A. WILSON², J.H. COWAN², S.J. BENTLEY², and T.A. HENWOOD³;  ¹University of South Alabama, Department of Marine Sciences, Mobile, AL, ²Department of Oceanography and Coastal Studies, Louisiana State University, Baton Rouge, LA, ³National Marine Fisheries Service, Southeast Fisheries Science Center, Pascagoula Laboratories, Pascagoula, MS. Delineating essential juvenile red snapper habitat in the north central Gulf of Mexico.

One of the most pressing issues facing federal fishery managers in the Gulf of Mexico is minimizing shrimp trawl bycatch of juvenile red snapper.  Recent studies suggest it may be necessary to augment the current bycatch reduction device (BRD) program to realize this management goal.  Area closure to shrimp trawls is one possible management tool; however, a greater understanding of juvenile red snapper production and habitat requirements is needed before area closure can be considered a viable option.  Toward this end, we have begun a research program to fill gaps in our understanding of red snapper life history and habitat requirements.  Our program consists of mapping geotechnical properties of the seabed with digital side scan sonar in areas that historically produced high, median, and low juvenile red snapper catch rates, and then examining contemporary differences in finfish and invertebrate community structure, as well as juvenile red snapper abundance, among habitats with trawl sampling.  Additionally, we are examining habitat-specific differences in juvenile red snapper diet and age and growth with analysis of stomach contents and otolith microstructure, respectively.  Results indicate our mapping approach is effective for delineating juvenile red snapper habitat and that juvenile red snapper abundance is correlated with habitat type.  Preliminary analyses also indicate ontogenetic effects on diet and habitat-specific effects on diet and age and growth exist.  Study results will be discussed in the context of juvenile red snapper essential fish habitat, as well as the problem of minimizing juvenile red snapper bycatch in shrimp trawls.

PAUTZKE, C. G. (cpautzke@nprb.org); North Pacific Research Board, Anchorage, AK.  Challenge of fisheries management:  balancing conservation and preservation of fish habitat.

Eight regional fishery management councils and the National Marine Fisheries Service (NMFS) are charged with managing fisheries outside three miles in accordance with ten national standards and other requirements in the Magnuson-Stevens Fishery Conservation and Management Act (Act) and other federal law. Regarding habitat, all fishery plans must describe and identify essential fish habitat using guidelines established by the Secretary of Commerce (Secretary). Managers must minimize to the extent practicable adverse effects caused by fishing and encourage conservation and enhancement of essential fish habitat. This paper summarizes habitat provisions in the Act and guidance provided by the Secretary, and explores habitat protection within the context of other issues facing managers.  The councils and NMFS are pressured not only to protect habitat from a wide range of fishing gears, but reduce bycatch, minimize impacts on stressed and endangered species, rebuild and maintain fish stocks, provide optimum yield, protect communities, promote safety, and simultaneously provide for economically feasible fisheries. This challenge, or dilemma, is particularly acute in Alaska's large commercial fisheries, and is the focus of this paper. Progress of other regional councils also is assessed in achieving an appropriate balance of conservation and preservation of fish habitat.  No easy formulas exist for how much habitat should be designated for fishing with certain gear types and how much should be preserved as marine protected areas.  The paper explores various options for achieving a suitable balance and identifies the research and data needed for managers to make informed decisions.

PERCIVAL, P. (philip.percival@ncl.ac.uk)*, C.L.J. FRID, R.C. UPSTILL-GODDARD; University of Newcastle, Dove Marine Laboratory, Department of Marine Science & Coastal Management, United Kingdom.  The impact of bottom fishing on early diagenetic transformations and benthic nutrient exchange.

Trawl disturbances to the seabed potentially cause a wide range of impacts that can modify remineralisation rates and alter sediment-water exchange of inorganic nutrients. Penetration of trawl gear, extending down to 15cm in soft sediments, is likely to have immediate impacts on nutrient exchange greater than those of bioturbation alone. Alterations in the redox status combined with additional organic matter, in the form of offal and discards in highly fished areas, are likely to have effects on benthic regeneration. However, the contribution of regenerated sources of nutrients from benthic systems is poorly understood. This study describes the impact of bottom fishing on early diagenetic transformations and benthic nutrient exchange. Replicate mesocosm systems containing sediment and fauna from a trawled area of the North Sea were allowed to stabilise. Following stabilisation three treatments were carried out. These included; 1, Trawl simulated disturbance at high intensity (disturbance on successive days). 2, Trawl simulated disturbance at lower intensity (disturbance on alternate days). 3, Control systems without any simulated disturbance. Nutrient concentrations were measured periodically within the overlying water of each system over a four-day period. These data were used to parameterise a model in order to estimate the flux of nutrients to the North Sea derived from trawling activity. The implications of the findings for direct nutrient exchange through direct trawl impact, bioturbation contribution and other biogeochemical implications are discussed and evaluated.

PICKRILL, R.A. (Dick.Pickrill@NRCan.gc.ca)* and B.J. TODD, Geological Survey of Canada (Atlantic), Dartmouth, Nova Scotia, Canada.  Sea floor mapping on the Scotian Shelf and the Gulf of Maine: implications for the management of ocean resources.

Multibeam sea floor mapping technologies have provided the capability to accurately, and cost effectively, image large areas of the seabed. Imagery provides base maps of sea floor topography from which targeted surveys can be planned to map sea floor sediments and associated benthic communities. Over the last five years extensive multi-disciplinary surveys have been carried out on Browns, German and Georges Banks. The government of Canada entered into a partnership with the scallop industry to map bathymetry, surficial sediments and benthic communities. The new knowledge has been used by industry, and has implications for fisheries management. Associations between substrate type and benthic community composition have enabled precise maps of scallop habitat to be produced and links between scallop abundance and substrate to be established. The environmental and economic benefits have been immediate, with reduced effort to catch set quota, less bottom disturbance, and containment of fishing activity to known scallop grounds. Stock assessments and management practices are improved. Other pilot projects in Atlantic Canada and the northeastern USA have demonstrated the value of integrated sea floor mapping in designating marine protected areas (The Gully, Stellwagen Bank), in identifying offshore hazards such as landslides, in siting offshore structures, cables and pipelines, and in addressing environmental issues such as the routing of outfalls and disposal of dredge materials. In recognition of the power of these new tools and digital map products, Canada is considering development of a national mapping strategy to provide the foundation for sustainable ocean management in the 21st century.

PIET, G.J. (g.j.piet@rivo.wag-ur.nl)*, J. CRAEYMEERSCH, and A.D. RIJNSDORP; Netherlands Institute for Fisheries Research (RIVO), Department of Biology and Ecology, IJmuiden, The Netherlands.  Changes in the benthic invertebrate assemblage following the establishment of a protected area, the 'plaice box'.

The ecosystem in the south-eastern North Sea is affected considerably by various sources of both natural and anthropogenic origin. The effect of a reduced beamtrawling effort on the benthic invertebrate assemblage could be studied from changes in the assemblage following the establishment of a protected area, the 'plaice box'. This area was established in 1989 and closed for all vessels with an engine power over 300 Hp, which constitutes the main part of the beamtrawling fleet. At first it was only effective part of the year but since 1995 the box was closed during the whole year. In order to be able to distinguish between this effect and that of potentially confounding influences from natural origin relevant environmental variables were incorporated in the analyses. The observed effects of the closure of an area on the benthic assemblage are discussed in the context of potential management measures and how to predict and assess their effectiveness and possible side effects.

PRANOVI  F. (fpranovi@unive.it)*¹, S. RAICEVICH¹, F. DA PONTE¹, and O. GIOVANARDI²;  ¹Dipartimento di Scienze Ambientali, Università Ca' Foscari, Venice, Italy, ²Istituto Centrale per la Ricerca scientifica Applicata la Mare (ICRAM), Venice, Italy.  Trawl fishing disturbance and medium-term recolonization dynamics: comparison between sandy and muddy habitats in the Adriatic Sea (Northern Mediterranean Sea).

Demersal gears scrape or plough the seabed, suspend sediment, alter sediment and water biogeochemistry, change sediment texture, and destroy bedforms. All this affects the processes and dynamics of benthic communities, which are directly impacted by the fishing gear. Presently a great scientific attention is being paid to a functional approach to better understand the constraints that drive and force the recolonization of benthic fauna subjected to fishing disturbance. The Northern Adriatic Sea is a wide trawlable area, which is intensively exploited by means of hydraulic dredges, otter-trawl and  'rapido'. The latter is a sort of beam-trawl used to catch flatfish on muddy bottoms and pectinids on sandy ones. This allowed comparisons between the dynamics of two different benthic communities subjected to the same kind of disturbance. The two study sites, located near a wreck and off a 'long-line' mussel culture, were experimentally trawled by means of a commercial rapido. We studied the recolonization dynamics on a nine-month basis, in terms of macrobenthic community structure, trophic groups and production analysed by means of mean body size of each taxonomic group. After 270 days the recovery is not yet complete, as confirmed by the differences recorded between controls and treatments. The pattern recorded in the two communities were quite similar: a 'scavenger effect' is revealed within 30 days after trawling and the differences between treatments and controls increase up to 90 days and then decrease.

PRESTON, J.M. (jpreston@questertangent.com)¹, A.C. CHRISTNEY¹, W.T. COLLINS*¹ and B.D. BORNHOLD²;  ¹Quester Tangent Corp., Sidney, British Columbia, Canada, ²Coastal and Ocean Resources Inc., Sidney, British Columbia, Canada. Seabed classification with multibeam sonars for mapping benthic habitat.

Seabed images, from multibeam systems or sidescans, convey a lot of information about seabed type.  Large-scale rocky relief often gives dramatic images, and morphology such as sand waves can be very evident.  Fine-grained sediments affect images in less obvious ways.  Statistical processing of the backscatter amplitudes generate features adequate for seabed classification that agree with both large-scale interpretation and fine-grained details.  Before calculating features, it is essential to precondition the image by compensating for artifacts due to range and grazing angle.  Useful features include ratios of integrals of the power spectrum over various frequency bands, descriptors of grey-level co-occurrence matrices and histograms, means and higher order moments, and fractal dimension.  Generating many features and then using multivariate statistical techniques to select the linear combinations that capture most of the variance in the dataset improves the quality and usefulness of the resulting classifications by adapting the classification to each set of images.  To complete the classification process, records are assigned to classes by the same clustering process used in the existing Quester Tangent classification products.  Maps of these acoustic classes show regions of distinct acoustic character, thus of distinct sediment type in some sense.  To make all this useful for benthic studies, one must understand how this acoustic diversity correlates with the distribution of species of interest.  Various spatial analysis techniques are available to accomplish this, and several examples of the integration of acoustic and benthic information will be presented.

PRESTON, J.M. (jpreston@questertangent.com)¹, A.C. CHRISTNEY¹, W.T. COLLINS*¹ and R.A. MCCONNAUGHEY²;  ¹Quester Tangent Corp., Sidney, British Columbia, Canada, ²National Marine Fisheries Service, Alaska Fisheries Science Center, Seattle, WA.  Quantitative measures of acoustic diversity to support benthic habitat characterization.

The fundamental dataset produced by an acoustic classification system is a representation of the acoustic diversity of the sediments in the survey area.  Each acoustic record, from a ping, a stack of pings, or a section of a sonar image, is transformed to a feature vector, typically in two or three dimensions.  Features may be from spectral analysis or from integration of parts of an echo envelope.  Rather than classifying sediments with just these few features, it is often more useful and adaptable to generate many features and use multivariate statistical techniques to select the linear combinations that capture most of the variance in the dataset.  Classification can then be done by dividing the records into groups based on the values of the most important, typically three, principal components.  A difficult step in this classification process is estimation of the appropriate number of clusters.  Motivated by the need for an automated seabed classification process that is both objective and adaptable to a wide variety of survey applications, this paper describes objective methods for choosing the number of clusters, based on information theory.  Actual classifications provide insights into acoustic diversity, which can be used as a proxy for change in sediment characteristics including the influence of benthos.  QTC IMPACT™ calculated 166 features from each stack of a very large set of echoes from the Bering Sea.  An optimum classification scheme, using the three most important principal components, was identified, based on K-means clustering guided by finding minima using information theory techniques.

QUIRÓS ESPINOSA, A. (cisam@civc.inf.cu)*, M:E. PERDOMO LÓPEZ and R. ARIAS BARRETO; Centro de Estudios y Servicios Ambientales; Ministerio de Ciencia, Tecnologia y Medio Ambiente, Santa Clara, Villa Clara, Cuba.  Controversy about trawling and Santa Maria Key«s causeway effects on seagrass.

In the winter of 1989, building of a causeway to Santa Maria key was started, 48 kilometers from the coast, in the central region of Cuba. Before the initial actions, the hydrological influence zones of this road were determined, and some ecological aspects were included in the executive project.  At the same time, a monitoring program was started, based on an initial assessment of the phytobenthos (biomass, diversity and functional groups). The monitoring took place in the springs of 1990, 1994 and 2002. Different sampling stations were located out of the causeway hydrological influences. In 1995, fishing activities began, using big trawls. The fishing zones are located in areas not influenced by the causeway, permitting comparison between the effects of fishing and the causeway on the phytobentos, mainly on seagrass. Between 1990 and 1994 no significant changes were observed in the control stations of the causeway monitoring.  A different situation was observed in 2002: the seagrass density decreased significantly and the algae diversity increased considerably as consequence of a lower spatial competition by Thalassia testudinum. A graphic model of the phenomenon was presented, including the effect on fishes, other fauna, vegetation, transparency, photosynthesis and sediment retention, that shows a case of positive feedback.

REID, J.A. (jareid@usgs.gov)*¹, C.J. JENKINS², M.E.FIELD¹, M. ZIMMERMANN³, S.J. WILLIAMS⁴, J.M. CURRENCE⁴, C.E. BOX¹ and J.V. GARDNER⁵; ¹ U.S. Geological Survey, Pacific Science Center, Santa Cruz, CA, ²INSTAAR, University of Colorado, Boulder, CO, ³National Marine Fisheries Service, Alaska Fisheries, Seattle, WA, ⁴U.S. Geological Survey, Coastal and Marine Geology, Woods Hole, MA, ⁵U.S. Geological Survey, Coastal and Marine Geology, Menlo Park, CA.  usSEABED: Towards unifying knowledge of geologic controls on benthic habitats.

The identification of benthic habitat is based, in part, on its underlying geologic character.  While some geologic characteristics can be inferred through bathymetry and remotely sensed imagery, knowledge based on actual sampling of the seabed, either through cores or through photography, can be expensive to collect, and in the latter case, difficult to quantify and assess. Hundreds of thousands of sediment cores, photographs, and videos have been collected along the continental shelves of the United States, in very large and very small research efforts, for various purposes and using a variety of equipment.  We unify these sets, both numerical lab-based data and word-based data from from core logs, photos, and videos, where we apply fuzzy set theory to parse values from graphed meanings.  These quantified combined data are mined for information useful for geologists, biologists, and ecologists into an linked information system, usSEABED, mappable in GISs and queriable in RDBs.  We present a ever-growing integrated look at the character of the surficial seabed of the United States (to about 100m depth, where available) that includes textural information, degree of hardness, presence of biota, basic chemistry, and critical shear strength, to name a few.  While these data are useful in their own right, most data held within usSEABED are available as baselines for habitat identification and assessment, or in combination with oceanographic, biologic, or geophysical data to a more complete understanding of a variety of critical processes necessary for effective resource management.

REID, R. (robert.reid@noaa.gov)*², F. ALMEIDA¹, P. VALENTINE³, L. ARLEN², J. CROSS², V. GUIDA², J. LINK¹, D. MCMILLAN², S. MURASKI¹, D. PACKER², J. VITALIANO², and A. PAULSON²;  ¹National Marine Fisheries Service, Northeast Fisheries Science Center, Woods Hole, MA, ²National Marine Fisheries Service, Northeast Fisheries Science Center, Highlands, NJ, ³U.S. Geological Survey, Woods Hole Field Center, Woods Hole, MA. The effectiveness of marine protected areas on fish and benthic fauna: the Georges Bank closed area I example.

In late 1994, a substantial portion of western Georges Bank was closed to commercial fishing (Closed Area I) to assist with stock rebuilding.  After about five years of closure, CAI, exhibited a notable increase in biomass and density of sea scallops, Placopecten magellanicus, and was reopened to the scallop fishery.  Before the industry was allowed entry into this area, we conducted a survey to monitor the recovery of benthic habitat and fauna inside CAI.  Sampling sites were selected in a paired station design for an inside/outside comparison; other stations were chosen to monitor the remainder of the inside.  At each station, we conducted video transects, collected still photos, CTD casts, and sediment samples for physical and chemical analysis.  A Smith-McIntyre bottom sampler was then used to sample the benthic community, followed by an otter trawl.  Trawl catches were sorted to species and all fish and invertebrates were weighed, enumerated, and measured.  Stomach contents, maturity observations, and age structures were collected for selected species at each station.  Our results suggest notable differences between paired stations for a suite of biotic and abiotic metrics ranging from grain size to fish biomass.  The reason for major differences is likely a result of the high relief, cobble habitat type in the region.  The differences we observed for CAI may have notable implications for the population dynamics of commercially valuable species.

REUTER, R.F. (rebecca.reuter@noaa.gov)*¹, C.C. COON², J.V. OLSON³, and M. EAGLETON³;  ¹National Marine Fisheries Service, Alaska Fisheries Science Center, Seattle WA, ²North Pacific Fisheries Management Council, Anchorage AK, ³National Marine Fisheries Service, Alaska Regional Office, Habitat Conservation Division, Anchorage AK.  Essential fish habitat (EFH) in Alaska: issues in consistency and efficiency when using geographical information systems (GIS) to evaluate effects to EFH.

The NMFS Alaska Region is presently drafting an Environmental Impact Statement (EIS) to evaluate a reasonable range of alternatives to develop the mandatory Essential Fish Habitat (EFH) provisions.  The process of updating habitat definitions and creating maps that describe EFH have led to basic questions about the standardization of map criteria.  Although national EFH GIS standards are suggested, there are regional differences, which will require specific standards for map criteria, such as projections, map features, and categories.  Currently within the Alaska Region, research and GIS data are summarized by management areas (e.g., Gulf of Alaska, Bering Sea and Aleutian Islands), which share common features such as depth, but do not necessarily overlap between areas.  For an Alaska Region project, such as the EFH EIS, an overall standard to make map production efficient is needed.  Therefore, interpretation of the data sets and maps will be consistent.  The standardization will assist NMFS scientists delineate EFH habitat types, depth strata, and species distributions.  Additionally, the overlays will provide background layers to assist fishery resource managers in identifying possible effects to EFH.  Thus, the completed GIS EFH product will allow NMFS to visually present how management decisions may appear in a geographic reference.  This poster presents an example of resolving these issues.

REUTER, R.F. (rebecca.reuter@noaa.gov)* and S. GAICHAS; National Marine Fisheries Service, Alaska Fisheries Science Center, Seattle WA.  Biodiversity changes in space and time in the Gulf of Alaska: an ecosystem measure of fishing effects on habitat.

Ecosystem resilience, in theory, is related to species and habitat diversity.  It is believed that high diversity in a system may act as 'insurance' against any type of disturbance.  Disturbance from fishing activities may result in diversity changes through time by the removal of select species and by gear effects on the bottom habitats. Historical bottom trawl survey data can be used to assess changes in diversity in the Gulf of Alaska.  Survey data collected between 1960 and 2001 was used to map and biologically classify benthic habitats in terms of species diversity for different classes of marine animals.  Although identification of benthic invertebrate species was limited by changing survey priorities, groundfish species such as rockfish and flatfish that occupy distinct habitat types were also used to classify areas.  A wide variety of diversity indices are available and in this study several were explored.  Maps of species diversity from pre-fishing trawl surveys were created using a geographical information system (GIS) and used to indicate historically important habitats.  Inclusion of fishery observer data, when analyzing these maps, may indicate possible fishery effects in heavily fished areas, and suggest natural rates of change in less fished areas.  This study will complement more direct experimental approaches for assessing fishing effects on benthic habitat by establishing the historical context of variability in an ecosystem.

RICE, J. (ricej@dfo-mpo.gc.ca); Department of Fisheries and Oceans, Science Advisory Secretariat, Ottawa, Ontario, Canada.  Multiple objectives, multiple players, multiple policies: better management, or more complex paths to the same old thing?

Like most developed countries, Canada is in the process of overhauling its approach to management of resources in the oceans.  Some initiatives arise from Canada's new Oceans Act (1997), others reflect the evolution of fisheries management policies and practices, and some reflect a growing interest by government as a whole in the role of science in effective decision-making.  Although details of various initiatives are uniquely Canadian, the major components have close parallels in the initiatives undertaken in many others jurisdictions, including Europe, the US, and the Southwest Pacific.  The talk will present the major pieces of the evolving approach to managing marine resources.  The pieces overlap and interact, of course, but each item represents a domain of focused activity in DFO.  The initiatives include (with the accountable sectors):

• Objectives-based Fisheries Management (Fisheries Management)
• Atlantic Fisheries Policy Review (Fisheries Management)
• Integrated Oceans and Coastal Management (Oceans)
• Ecosystem Objectives (Oceans & Science)
• Precautionary Approach (Science, Oceans, & Fisheries Management)
• Marine Protected Areas (Oceans)
• Stewardship & Co-management (Fisheries Management & Oceans)
• Science Advice for Government Effectiveness (Science)

Descriptions of the initiatives will be brief, because similar ones are occurring in everyone's backyards.  The ways that the various initiatives could interact constructively and could interfere with each other will be developed more fully.  Anecdotes will be kept to a minimum.  With the new initiatives presented, the talk will review the issues associated with impacts of fishing on benthic habitats in Canada.  The potential contributions of the various Departmental initiatives to addressing these issues will comprise the core of the talk.  The management initiatives will be considered individually and in combination.  Where we are gaining experience with real-world application of the initiatives, that experience will be the basis for critical evaluation.  The talk will conclude with personal observations, based on over two decades of working with scientists, managers, industry, and environmentalists, with regard to effective paths to progress.

RIESER, A. (rieser@maine.edu); University of Maine School of Law, Portland, ME.  The legal requirement to address fishing effects on essential fish habitat: thresholds, qualifiers, and the burden of proof.

The 1996 Sustainable Fisheries Act (SFA) requires fisheries managers to describe and identify the essential fish habitat of all managed fish stocks in the U.S. EEZ.  The law also requires managers to 'minimize to the extent practicable adverse effects on such habitat caused by fishing.'  In addition to the practicability language, the SFA's fishing effects mandate is qualified by the Act's overall requirement that conservation and management measures 'shall be based upon the best scientific information available.'  The National Marine Fisheries Service's (NMFS) 1997 EFH guidelines, requiring councils to mitigate when there was evidence of  'identifiable adverse effects,' gave little additional understanding of the threshold for 'adverse effects' that would trigger the need for mitigation measures.  In the first generation of EFH amendments, the practicability standard did not come into play because most councils concluded there was inadequate scientific information regarding the seafloors and fishing gear impacts in their region to warrant the development of mitigation measures, whether practicable or not.  Conservation groups challenged the Secretary's approval of five of the regional councils' EFH amendments, claiming the councils had not taken into account the growing scientific consensus that bottom trawling and dredging can have significant ecological effects.  Government lawyers defending the Secretary's action convinced the court that the amendments were adequate because the agency interpreted the SFA's EFH and 'best available science' standards to require site-specific scientific information that particular fishing practices or gears are having identifiable impacts on particular habitats within the council's region.  In deferring to this interpretation, the court thus established that the 1996 provisions require more detailed scientific evidence to cross the threshold for 'adverse effects' than was then available for each region.  More important, however, was the court's conclusion that the decision-making process for approving the EFH amendments was deficient under the National Environmental Policy Act (NEPA) because NMFS failed to take a 'hard look' at the environmental consequences of fishing practices and gears.  NEPA required the agency to analyze a broader range of feasible alternatives for protecting EFH from fishing activities than the status quo alternatives recommended by the councils.  Under a court-approved settlement agreement, NMFS and the councils must prepare new environmental impact statements that will improve their EFH identifications and consider a range of alternative approaches to the fishing effects question.  This second generation of EFH actions is likely to differ significantly from the first for several reasons.  First, NMFS has directed the councils to consider all scientific information currently available regarding fishing effects, a body of literature that has increased considerably since 1997-98 when the first EFH amendments were prepared and approved.  Moreover, NEPA does not have a 'best available science' requirement, a standard NMFS used implicitly to justify its limited efforts to require protective EFH amendments.  The councils will also need to consider the National Academy of Sciences' 2002 report, 'The Effects of Trawling and Dredging on Seafloor Habitat,' which concludes that seafloor habitat should and can be effectively protected from gear impacts in the absence of site-specific information.  The report describes a comparative risk analysis process that NMFS and the councils can use in the face of scientific uncertainty.  This risk analysis process is a form of structured decision-making the National Academy of Sciences' panel on science and the Endangered Species Act recommended agencies use when conservation decisions must be made with incomplete information and where conflicting social values are at play.  There is also a strong possibility that Congress will soon amend the EFH and fishing effects mandate as well as the 'best available science' requirement.  The 107^th Congress is considering competing bills that would define in more detail how science-based fishery management decisions are to be made in the face of uncertain scientific information.  Thus, the next round of EFH amendments and bycatch provisions are likely to be reviewed for approval under very different thresholds, qualifiers, and burdens of proof.

ROBINSON, L.A. (l.a.robinson@ncl.ac.uk)* and C.L.J. FRID; University of Newcastle upon Tyne, Department of Marine Sciences and Coastal Management, Dove Marine Laboratory, Tyne & Wear, United Kingdom.  Extrapolating extinctions and extirpations: searching for the pristine state of the benthos.

Mechanised fishing has a long history and exploitation of marine ecosystems began decades before any ecological studies were undertaken.  Scientists therefore face a major constraint when trying to establish baseline or 'pristine' levels of ecological qualities.  Fishing can impact benthic systems both directly and indirectly.  It has been suggested that the changes in abundance of certain 'vulnerable' taxa may act as indicators of particular disturbances, including the direct effects of bottom trawling.  The question must be asked however, as to whether over the period in which fisheries disturbance has been occurring, any such sensitive benthic species have become extinct or at least extirpated from heavily fished areas.  The recent palaeoecological records of 4 benthic phyla from the North Sea were examined and a picture of the unimpacted system constructed.  This was compared with contemporary records and 5 species from 2 phyla were found to be absent from modern North Sea communities.  Several other species had become extirpated regionally, mainly from the southern North Sea, an area subject to heavy fishing effort with heavy gears.  Attributes that may increase the vulnerability of fauna to bottom trawling were derived a priori form the literature and the species that had disappeared were examined for the presence of these.  Many of the taxa that had become extripated did not show the features indicative of vulnerability to the direct impact of fishing gear.  In the light of this it may be premature to attribute all the extirpations to fishing effects on the benthic ecosystem.

ROSE, C.S. (craig.rose@noaa.gov); NOAA National Marine Fisheries Service, Alaska Fisheries Science Center, Seattle WA.  The characteristics and function of commercial fishing gears: how these relate to their effects on seafloor habitats and the pursuit of ways to minimize effects.

Of the factors that influence the effects of fishing gear on benthic ecosystems, the characteristics of the fishing gear may be as significant as the characteristics of the physical habitat or the community of organisms affected. While the effects of different fishing gear components on benthic ecosystems may have general similarities, variations in particular gear characteristics, such as force of bottom contact, and component dimensions, could cause profound differences in the severity of such effects.  Few studies have addressed such distinctions and much of the relevant information has been collected incidental to studies with other goals, such as during research of fishing gear selectivity and related fish behavior. This has limited the usefulness of gear selection and modification in reducing seafloor effects. This paper will categorize and describe the identified effects of fishing, noting which characteristics of fishing gear components affect the severity of each effect.  We will also describe the main components of the major classes of fishing gears and relate them to these significant characteristics.  This background will be used to motivate and describe several concepts of gear modifications to reduce seabed effects.

ROSE, C.S. (craig.rose@noaa.gov)* and E. M. JORGENSEN; NOAA National Marine Fisheries Service, Alaska Fisheries Science Center, Seattle WA.  Spatial and temporal distributions of trawling intensity off of Alaska: Connecting the small scale to issues on an ecosystem scale.

The spatial and temporal distribution of fishing effort is a critical component of the assessment of fishing gear effects on the benthic environment. Fishing intensity influences the intensity of effects, the time available for recovery and the fine scale pattern of affected and unaffected habitat. To meaningfully model ecosystem level effects, effort information needs to be extensive on a regional scale, yet of fine enough resolution to account for the aggregated nature of fishing efforts.  Available data generally falls short of this mark. The most extensive and detailed of the U.S. regional effort databases has resulted from the observer programs off of Alaska. This paper examines Alaska bottom trawl effort in recent years to estimate the distribution of fishing intensity on both large and small scales. Binning of data into 5 x 5 km squares shows the distribution of average fishing intensities as a percentage of available seafloor and the variability of intensity across regions, depths and years. Examination of finer scale data from vessel monitoring and GPS recordings shows the distribution of actual intensities, that is the proportion of a block encountered no times, once, twice etc. Combination of the two data types allows estimation of the proportion of  larger seafloor areas encountered at each intensity level in a year and also the expected recovery time available until the next encounter. Such estimates are needed to connect the results of small-scale experiments to models of regional effects.

RUBEC, P.J. (peter.rubec@fwc.state.fl.us)*, A. JACKSON, C. ASHBAUGH, and S. VERSAGGI; Florida Fish and Wildlife Conservation Commission, Florida Marine Research Institute, St. Petersburg, FL.  Development Of an electronic logbook to assess shrimp-trawl catch, effort, and associated environmental data in areas fished off Florida and Texas.

An electronic logbook (ELB) system was developed and evaluated by Florida Marine Research Institute (FMRI) biologists in collaboration with a shrimp company and an electronics firm, both based in Tampa, Florida.  The software compiles shrimp-trawl catch, and effort data entered onto a computer situated on the bridge, and environmental data transferred from a conductivity-temperature-depth (CTD) data logger.  A Vessel Monitoring System (VMS) was integrated with the ELB to capture geographic positions and transmit data to the shrimp-company headquarters and to FMRI.  The system was evaluated on an FMRI research vessel and then on three shrimp vessels.  Data obtained using the ELB system indicated that pink shrimp (Farfantepenaeus duorarum) caught off the west coast of Florida (March-June 2001) and brown shrimp (Farfantepenaeus aztecus) caught off the coast of Texas (July-September 2001) exhibited different preferences for environmental conditions.  The highest mean catch rates (CPUEs) of pink shrimp occurred over sand and hard bottoms when the temperature was 20-24.9°C.  Pink shrimp had no apparent preference for any particular salinity or depth range.  The highest mean CPUEs of brown shrimp occurred over mud bottom, at temperatures of 25-29°C, and at salinities of 35-39.9 g/L.  Brown shrimp did not exhibit a preference for any particular depth range. These results indicate that the ELB system has the potential to assist the fishery in locating areas where shrimp are abundant.  Further development of the system would benefit both the shrimp fishery and fisheries management.

SCANLON, K.M. (kscanlon@usgs.gov)*¹, F.C. COLEMAN², and C. C. KOENIG²;  ¹U. S. Geological Survey, Woods Hole, MA, ²Department of Biological Science, Florida State University, Tallahassee, FL.  Recognizing habitat modifications by fish in the Gulf of Mexico.

Some fish species (e.g., tilefish and red grouper) that are targeted by commercial and recreational fishers are known to burrow, excavate large holes, clear sediment away from rocky outcrops, or otherwise modify the seafloor portion of their habitat.  Recognizing these features in the field and differentiating them from other natural seafloor features (such as gas-generated pockmarks or current scour) or anthropogenic features (such as artificial reefs or dump sites) is important for fishery management, but can be a challenging task.  The U.S. Geological Survey, in cooperation with NOAA's National Marine Fishery Service and Florida State University, has collected a suite of geophysical and observational data from such fish-modified habitats in the eastern Gulf of Mexico.  The data include relatively low-resolution multibeam bathymetry and backscatter, higher-resolution sidescan-sonar imagery, and very high-resolution observations and samples from ROVs and submersibles. We will compare examples of features created by fish with features created by other natural processes or of anthropogenic origin.  Feature attributes such as spacing, size, and uniformity, which can be determined from a variety of image data, can be used to suggest the feature's origin.  Additional geologic or oceanographic information, such as composition and texture of the substrate, configuration of subsurface horizons, and current velocity, may be necessary to ascertain the feature's origin.  We will suggest criteria for recognizing fish-modified habitat that can be applied to habitat mapping in the Gulf of Mexico and elsewhere.

SCHOLZ, A. J. (ajscholz@ecotrust.org)*, M. MERTENS, C. STEINBACH, M. BELLMAN, and D. SOHM; Ecotrust, Portland, OR. Place matters: spatial tools for assessing the socioeconomic implications of marine resource management measures on the Pacific coast.

Fishery management measures such as the reduction of the groundfish fleet capacity considered by the Pacific Fishery Management Council, and conservation measures such as networks of marine protected areas being implemented in federal and state waters have considerable socioeconomic impacts. Users of marine resources, such as commercial and recreational fishermen, boaters, divers and others experience direct and indirect costs and benefits from such measures - notably foregone earnings and changing economic opportunities. In this paper we present results and tools from a year-long project to build an integrated, spatially explicit analytical framework for assessing six management scenarios: three numerical reductions of the West Coast groundfish fleet using a number of criteria, and three policy-driven scenarios that reflect current management priorities - permit stacking, individual quotas and marine protected areas. Using an extensive relational database comprising fishery dependent, ecological, and socioeconomic data, we built a regional Geographic Information System (GIS) and assessed the relative impacts of the six management scenarios.  The results are spatially explicit, and are specific to particular communities, gear groups, fishing fleets and ecological habitats, thus allowing decision-makers to consider a range of issues that present themselves in management situations. The GIS makes for an intuitive interface that allows for participatory and consensus-oriented processes.

SHERIDAN, P. (pete.sheridan@noaa.gov); NOAA Fisheries, Southeast Fisheries Science Center, Galveston TX. Short-term effects of the cessation of shrimp trawling on Texas benthic habitats.

I examined evidence for short-term effects of a seasonal closure on essential fish habitat of the shallow Gulf of Mexico. I compared benthos and sediments of two adjacent areas of the middle Texas coast, one of which (south zone) was closed to all shrimp trawling within 9.3 km (5 nmi) of shore during 1 December 2000 - 8 July 2001. I hypothesized that lack of trawling would result in accumulation of fine surficial sediments, leading to increased proportions of silt and clay and decreased proportions of rubble and sand. I also hypothesized that trawling activity would disrupt benthic community structure leading to altered types and densities of major taxa. I used GIS to develop random stratified sampling sites based on sediment characteristics of each block. During 18-22 June 2001, divers collected benthos and sediment cores from 32 sites in each block. No significant differences in mean proportions of rubble, sand, silt, clay, or organic matter were detected between north and south sediments. Densities of numerically abundant taxa, including structure providers such as soft corals, were also similar between zones. This section of the coast receives the highest trawling effort in <20m depths off Texas (annual mean = 40 hr per sq. km). By comparison, this trawling effort is an order of magnitude less than that seen at similar depths off Louisiana. Ambient trawling effort during winter and spring months has no apparent effect on sediments or benthos in the shallow waters off central Texas. Verification by experimental manipulation of effort is needed.

SIMPSON, A. W. (anne.simpson@umit.maine.edu)* and L. WATLING; University of Maine, Darling Marine Center, Walpole, ME.  Physical and biological effects of shrimp trawling on soft sediment habitats in the Gulf of Maine.

Mobile gear fisheries are a pervasive source of disturbance in marine habitats that can directly alter both the physical and biological structure of the benthic environment.  In the Gulf of Maine, muddy bottoms are intensively trawled for northern shrimp during a seasonal winter fishery.  We collected sediment samples from trawled and untrawled areas every 80 to 120 days over an 18-month period.  Detailed bulk density measurements from sediment x-radiographs reveal that shrimp trawling may alter the sedimentary 'landscape'.  Our findings suggest that in areas where biogenic disturbance is high due to the activities of large burrowing megafauna such as fish and crustaceans, discerning impacts of shrimp trawling on the structure of infaunal communities is difficult; however, trawling appears to reduce the overall density of large burrows.

STEELE*¹, J. (jsteele@whoi.edu) and S.J. ROBERTS²;  ¹Marine Policy Center, Woods Hole Oceanographic Institution, Woods Hole, MA, ² National Research Council, The National Academies, Washington, DC.  The results of the National Research Council study on the effects of bottom trawling and dredging on seafloor habitats.

The NRC study committee concluded that assessment of the ecological effects of trawling and dredging requires consideration of three factors: (1) gear-specific effects on various types of habitats, (2) fishing effort intensity and distribution, and (3) physical and biological characteristics of seafloor habitats. Although there are information gaps for each factor, currently available data can be better used to reduce effects on the seafloor. Analysis of trawling and dredging effort data is currently limited by low spatial resolution and regional variation in reporting methods. Even in heavily trawled regions, effort is not uniformly distributed; hence some areas may be trawled often while other areas are trawled infrequently if at all. Although trawling can be destructive in ecologically vulnerable habitats, some habitats are resilient to the effects of trawling, especially sandy habitats that experience naturally high levels of disturbance. Trawling does not enhance the productivity of seafloor communities, though some species may become relatively more abundant. Management measures - effort reductions, area closures, and gear modifications - should be tailored to the social and economic characteristics of the fishery and the biological characteristics of the habitat. Comparative risk assessment can be used to assess impacts when insufficient data are available for quantitative analysis. Also, the assessment process provides an opportunity for stakeholder involvement in developing management alternatives. Establishment of guidelines for designating EFH and HAPC based on standardized, ecological criteria and development of a national habitat classification system would help managers mitigate the effects of bottom trawling.

STEVENSON, D. K. (David.Stevenson@noaa.gov); U.S. National Marine Fisheries Service, Northeast Regional Office, Gloucester, MA.  Spatial distribution of fishing activity for principal commercial fishing gears used in the Northeast region of the United States, 1995-2000.

Numbers of fishing trips, days-at-sea, and fishing days made by federal commercial fishing vessel permit holders were compiled from logbook data and assigned to 10 minute 'squares' of latitude and longitude to show spatial distribution patterns for 18 individual gear types and 3 major gear categories in the northeast United States (North Carolina - Maine) during 1995-2000.  Principal gear types included in the analysis were otter trawls (fish), lobster pots, handlines, otter trawls (shrimp), hydraulic clam dredges, scallop dredges, quahog dredges, sink gill nets, and bottom longlines.  GIS plots of days-at-sea (otter trawls and scallop dredges) and fishing time (clam dredges) accounted for geographical variations in trip duration and thus provided unbiased distributions of fishing effort for mobile bottom gear types.  The distributions of scallop dredge days-at-sea in 1998 and 1999 closely resembled plots of fishing activity that were derived on a much finer time and spatial scale from vessel tracking system signal data (McSherry and Rago 2001).  Overlays of ten minute squares that accounted for 90% of all days-at-sea or fishing time on bottom sediment data for the northeast U.S. continental shelf showed that most scallop dredging takes place on sand and gravel bottom, clam dredging in sand, and otter trawling on a variety of bottom types.

STOKESBURY, K.D.E. (kstokesbury@UMassD.Edu)* and B. Harris; School of Marine Science and Technology, University of Massachusetts Dartmouth, New Bedford, MA.  A before-after-control-impact study of the sea scallop fishing grounds of Georges Bank.

A Before-After-Control-Impact (BACI) study is the optimal environmental impact experimental design. The null hypothesis is "an impact resulted in no biological damage". Fisheries management often relies on time series of data but unless there is a control all before-after comparisons must assume homogeneity over time, an assumption that has been found invalid time and again. We surveyed the historic scallop fishing grounds of Georges Bank that have been closed to mobile gear since 1994. We employed a BACI design with a 1-year set of baseline observations, two experimental areas that were exposed to intense fishing pressure, two control areas with no fishing, and one control with constant fishing. Within each experimental area we conducted a high-resolution video survey using a multistage design with stations separated by 0.85 nautical miles. The video survey was based on sea scallop densities to obtain a 5% to 15% level of precision for the normal and negative binomial distributions, respectively.  Mounted on the pyramid were two video cameras and several lights. Four quadrat images (2.8 m²) of the sea floor including counts and sizes of scallops, other macroinvertebrates and benthic fishes and sediment types, were relayed in real time to the surface. These images were video taped and the exact position (latitude and longitude from differential GPS) depth, and time. During all surveys the same stations were sampled. Changes in species composition, density and distribution macroinvertebrates and groundfish, and in sediment structure will be compared.

STONE, R. P. (bob.stone@noaa.gov)*, M. M. MASUDA, and P. W. MALECHA; Auke Bay Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, Juneau, AK.  Spatial distribution and abundance of epifauna on adjacent soft-bottom areas open and closed to bottom trawling in the Gulf of Alaska.

The spatial distribution and abundance of epifauna were studied at 3 sites in the central Gulf of Alaska where bottom trawling had been prohibited for 11 to 12 years.  These areas were closed to assist in rebuilding severely depressed crab stocks.  Continuous video footage of the seafloor was collected with an occupied submersible along 41 strip transects.  Transects were bisected by the boundary demarcating open and closed areas to bottom trawling at each site.  Trawling intensity at the sites was estimated at 11 - 29% of the seafloor per year for the 5 years preceding this study.  All megafauna (> 4 cm) were enumerated and their relative position on the seafloor determined.  Counts at one site were not completed due to the existence of a natural habitat gradient that confounded any differences between open and closed areas to bottom trawling.  At the other two sites, positions of over 150, 000 megafauna were determined along 89 km of seafloor.  Differences in abundance of sedimentary biogenic structures were also examined.  These data will form the basis for determining if ambient levels of bottom trawling, in some of the more intensely trawled areas in the Gulf of Alaska, have changed these soft-bottom marine communities.

STONER, A.W. (al.stoner@noaa.gov)*¹, C.L. RYER¹, and R.A. McCONNAUGHEY²;  ¹Alaska Fisheries Science Center, NOAA National Marine Fisheries Service, Hatfield Marine Science Center, Newport, OR, ²Alaska Fisheries Science Center, NOAA National Marine Fisheries Service, Seattle, WA.  Ecological consequences of lost habitat structure for commercially significant flatfishes:  habitat choice and vulnerability to predators.

Numerous field studies, both descriptive and experimental, have shown that fishing gear can have a negative impact on the structural complexity of benthic environment.  Impacts in high-relief habitats such as coral reefs, hard-bottom, seagrasses, and cobble are well documented.  Soft-bottom habitat can also contain physical structure created by different bedforms, sessile invertebrates such as sponges, anemones, soft corals, and bryozoans, and the empty shells of molluscs.  Recent laboratory experiments with Alaska flatfishes show that age-0 and age-1 fish have a strong behavioral affinity for sediments structured with sand waves, sponges, bryozoans, and bivalve shells.  Responses were stronger in juvenile Pacific halibut than rock sole.  The presence of structured habitat also affected the survivorship of age-0 fishes in the presence of a piscivorous predator, but habitat-mediated predator-prey interactions varied with prey species.  Comparisons of trawled and untrawled locations in the Gulf of Alaska and the Bering Sea reveal that densities and biomass of sponges, anemones, bryozoans, gastropod shells, soft corals, and other biota providing structure for small fishes decrease with fishing activity.  It follows that loss of structured habitat in low-relief shelf environment can have both direct and indirect impacts on the function of habitat for demersal fishes, particularly during their first year of life.  We need a better understanding of how structural complexity in soft-bottom environment influences abundance and recruitment of fishes and invertebrates, and better characterization of habitat features is probably required.

STRAND, M. P. (strandmp@ncsc.navy.mil); Naval Surface Warfare Center, Coastal Systems Station, Panama City, FL.  Fluorescence imaging laser line scan (FILLS) imagery for high-resolution benthic habitat characterization.

Laser-based underwater imaging sensors have been developed and matured in the last decade that provide high resolution optical imagery of the sea floor.  Laser Line Scan (LLS) and Streak Tube Imaging Lidar (STIL) have been particularly successful.  A prototype Fluorescence Imaging Laser Line Scan (FILLS) sensor has been deployed in several underwater environments, yielding high-resolution (~1 cm pixel size) imagery of the associated benthic habitats. The prototype FILLS sensor illuminates the sea floor with 488 nm laser light, and constructs four independent images from light collected at 488 nm, 520 nm, 580 nm, and 685 nm, respectively.  The 488 nm image is formed from elastically scattered light (i.e., light scattered with no change in photon energy), while the other images are formed by inelastically scattered light. (The FILLS sensor is routinely operated during nighttime hours so that ambient illumination is negligible).  Fluorescence is the primary physical mechanism giving rise to the inelastically scattered light sensed by FILLS. Coral reef environments produce particularly strong (and spectacular!) fluorescence imagery.  FILLS was developed primarily for the detection, classification, and identification of man-made objects in underwater environments.  In addition it can serve admirably for the characterization of underwater habitats. Examples of FILLS imagery relevant to fish habitat evaluation will be presented.

SULLIVAN, M.C. (msullivan@rsmas.miami.edu)*¹, R.K. COWEN¹, K.W. ABLE², and M.P. FAHAY³;  ¹Rosenstiel School of Marine and Atmospheric Science, Department of Marine Biology and Fisheries, University of Miami, Miami, FL, ²Marine Field Station, Institute of Marine and Coastal Sciences, Rutgers University, Tuckerton, NJ, ³National Marine Fisheries Service, Northeast Fisheries Science Center, Sandy Hook Laboratory, Highlands, NJ.  Scaling of natural and anthropogenic disturbance on the New York Bight shelf: Implications for tilefish communities of the shallow continental slope.

Trawling is a pervasive feature of continental shelf environments worldwide. However, commonalities within individual systems and among habitat types and species are rarely clear cut. Our recent work in the New York Bight apex examined the potential impact of mobile fishing gear within a storm-dominated shelf system. Over medium-grain sand sites, scallop dredging was shown to have minimal short-term effects (hours-day) on the abundance of a common, juvenile flatfish (Limanda ferruginea) and its benthic prey (gammarid amphipods, cumaceans). Longer-term impact signatures (months-year), however, were completely obscured by intense physical forcing during the fall (hurricanes) and winter (northeasters) months. Clearly, the intersection between habitat type and prevailing physical regime plays a critical role in defining the susceptibility of marine ecosystems to anthropogenic stress. Thus, an area of immediate concern is the shallow continental slope where natural disturbance is minimal and chronic trawling activity disproportionately high. The tilefish, Lopholatilus chamaeleonticeps, a long-lived, benthic excavator, plays a fundamental role in creating heterogeneity in these low variability habitats and has been compared to other 'ecosystem engineers' which alter bottom types favorably for members of lower trophic levels. Tilefish and their commensal associates (i.e. Helicolenus dactylopterus, Anthias spp.) appear particularly vulnerable to significant direct (as bycatch) and indirect (habitat alteration) impacts by mobile bottom fishing gear. Ongoing work is investigating the consequences of chronic trawling, as well as individual trawling events, on tilefish communities in these remote underwater habitats.

THRUSH, S.F. (s.thrush@niwa.cri.nz)*, C. LUNDQUIST, and J.E. HEWITT; National Institute of Water and Atmospheric Research, Hamilton, New Zealand. Spatial and temporal scales of disturbance to the seafloor: A generalised framework for active habitat management.

The direct effects of marine habitat disturbance by commercial fishing have been well documented.  However, the potential ramifications to the ecological function of seafloor communities and ecosystems have yet to be considered.  Ecological research has demonstrated that natural disturbance processes play an important functional role in seafloor ecosystems by affecting spatial heterogeneity.  When the space and time scales of human disturbance are greater than those the natural ecosystems are adapted to, then changes in community structure and function are inevitable.  Functional extinction, due to changes to disturbance regimes restricting the size, density and distribution of organisms, threatens resilience at all levels of biological diversity.  This is particularly true in soft-sediments, where the organisms create much of the heterogeneity and also play crucial roles in many processes.  Thus there is a need to develop a scientific framework for the management of seafloor habitat focussing on sustaining fisheries and maintaining biodiversity.  Simple heuristic models can indicate disturbance regimes that, through their frequency, extent or intensity, could result in catastrophic change across the seafloor landscape.  Our model simplifies many of the complexities of disturbance-recovery dynamics, but can be used to both highlight areas of future research and provide a framework for developing more spatially explicit management strategies.  Moreover, even such a simple model emphasises the need to understand the scales of mobility and the processes affecting recovery.

THURMAN, P. E. (Paul.thurman@fwc.state.fl.us)*1, G. Dennis2, K. Sulak2, and R. S. McBride1; 1Florida Marine Research Institute, St. Petersburg, FL, 2U.S. Geological Survey, Florida Caribbean Science Center, Gainesville, FL.  Linking predator and prey species dynamics in deep-water reefs of the northeastern Gulf of Mexico.

Deep-water reefs common to the Gulf of Mexico provide essential habitat for economically important species such as red snapper (Lutjanus campechanus), grouper (Epinephelus/Mycteroperca spp.), and amberjack (Seriola spp.).  Recent diet studies of these predators indicate small serranids (<150mm SL) such as roughtongue bass (Pronotogrammus martinicensis) and red barbier (Hemanthias vivanus) are an important link between zooplankton and these predators.  Life history data and video population estimates are being analyzed to determine if these predators affect the size and age structure, distribution, and abundance of these prey species.  Ages of 182 P. martinicensis and 80 H. vivanus were estimated by examining the ring structure on whole sagittal otoliths.  Although we cannot validate the periodicity of ring formation until year-round samples have been examined, most of the fish collected during May had a ring that was either newly formed or on the margin.  Individuals of both prey species grew rapidly through their first year and then growth slowed significantly.  Modal ages of P. martinicensis and H. vivanus were 3 and 4 years, respectively.   The oldest P. martinicensis examined was 8 years and the oldest H. vivanus was 7 years.  These preliminary estimates of ages were higher than anticipated and indicate a fairly stable age-structure for these species.  Previous work has suggested that changes in predator abundance can affect prey population dynamics.  Therefore, monitoring the prey species could provide information that can be used to determine the status of the predators in areas of differing regulatory regimes.

UHRIN, A.V. (Amy.Uhrin@noaa.gov)*¹, M.S. FONSECA¹, and G.P. DIDOMENICO²;  ¹National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Fisheries and Habitat Research, Beaufort, NC, ²Monroe County Commercial Fishermen, Inc., Marathon, FL.  Effect of lobster traps on seagrass beds of the Florida Keys National Marine Sanctuary (FKNMS): damage assessment and evaluation of recovery.

In the Florida Keys, spiny lobster traps are often deployed in seagrass beds. Given that several hundred thousand traps may be deployed in one season, the possibility exists for significant impacts to seagrass resources. The question is whether standard fishing practices observed in the fishery actually result in injuries to seagrass.  This study was designed to measure the degree of trap injury on seagrass beds as a function of the duration of trap deployment (soak time) and habitat type (seagrass species) and the recovery thereof.  Thirty treatment plots were randomly assigned within each of two monospecific seagrass beds (Thalassia testudinum and Syringodium filiforme) near Marathon, Florida.  Five plots remained trap-free (controls) while the remaining plots each received a single trap.  Five replicate traps were randomly removed at each of five soak times (one, two, four, and six weeks, and six months).  Immediately following trap removal, seagrass short shoot densities were recorded and compared among control and treatment plots.  Both seagrass species exhibited significantly decreased densities after six-week and six-month soak times.  T. testudinum densities within the six-week treatments had returned to control densities four months after trap removal while S. filiforme densities remained significantly decreased.  We conclude that traps must be recovered within a six-week period, beyond which, injury to seagrass beds is predicted.  Within the limits of these testing parameters, it appears that standard fishing practices (typically < 5-week soak time) should not result in a significant injury to seagrass beds in the Florida Keys.

UPTON, H.F. (Hupt8481@postoffice.uri.edu)* and J. G. SUTINEN; Department of Environmental and Natural Resource Economics, University of Rhode Island, Kingston, RI.  Tradeoffs associated with the use of closed areas to conserve habitat: Consideration of New England groundfish and sea scallop fisheries.

Our paper examines the economic costs of protecting Essential Fish Habitat (EFH) by closing areas to groundfish and scallop fisheries on Georges Bank. We then consider how these costs compare to the potential benefits of EFH protection. Many experimental studies have documented gear effects of trawling and dredging on different types of habitat. These fishing activities can reduce habitat complexity by removing or damaging biological and physical benthic structure. Protection of the services provided by the environment in which fish live, grow and reproduce may be the most important benefit associated with permanent area closures. Marine fish habitat is heterogeneous with vulnerability that may be characterized by substrate type and hydrodynamic forces such as waves and ocean currents. Therefore, specific areas are likely to incur the greatest habitat damage and provide the greatest benefits if closed to mobile gear. Our study attempts to quantify the foregone net revenues associated with potential area closures of groundfish and sea scallop fisheries on Georges Bank. Potential closures are determined according to habitat vulnerability as identified by methods developed by DeAlteris et al. (2000). The mobility of fishing effort is also modeled to include the response of fishers to the management measure. Although sufficient knowledge of ecological linkages between habitat quality and groundfish productivity is not available, we provide the commensurate gains to the groundfish fishery that would just balance the costs of closures. These gains are then be assessed to determine whether they are within a feasible range, and if further study is warranted.

VALENTINE, P.C. (pvalentine@usgs.gov)*1, B.R. TODD2, and V.E. KOSTYLEV2; 1U.S. Geological Survey, Woods Hole, MA, 2Geological Survey of Canada (Atlantic), Dartmouth, Nova Scotia, Canada.  Regional habitat classification as applied to the marine sublittoral of northeastern North America.

Habitats can be defined as spatially recognizable areas where the physical, chemical, and biological environment is distinctly different from surrounding environments.  Implicit in this definition is the question of scale.  A habitat can be defined as narrowly or as broadly as the data and purpose permit, and this flexibility of scale influences the development of habitat classification schemes.  Recent classifications focus on a wide range of habitats that occur in European, United States, and worldwide sea floor environments.  The regional classification proposed here is based on recent studies in the Gulf of Maine using multibeam and sidescan sonar surveys, video and photo transects, and sediment and biological sampling.  The goal is to develop a practical method to characterize the marine sublittoral habitats of northeastern North America not just in terms of (1) their geological, biological, and oceanographic attributes, but also in terms of (2) the natural and anthropogenic processes that affect the habitats.  The scheme is a four level hierarchy in which the three higher levels, classes (see table), subclasses and categories (not shown), are applicable worldwide, while the lowest level (attributes, not shown), describes regional habitat characteristics.  Classes 7 and 8 are included to address the growing importance of habitat information to the management of fisheries and environments.  The classification is expandable at all levels, and into all regions and habitats.  It serves as a template for a database, thus providing a method for organizing and comparing habitat information.

VALENTINE, P.C. (pvalentine@usgs.gov)*¹, J. B. LINDHOLM ^2,3, and P.J. AUSTER³;  ¹U.S. Geological Survey, Woods Hole, MA, ²NOAA's Stellwagen Bank National Marine Sanctuary, Scituate, MA, ³National Undersea Research Center at the University of Connecticut, Groton, CT. Bottom trawling effects on cerianthid burrowing anemone aggregations and Acadian redfish habitats in mud to muddy gravel seabeds of the Stellwagen Bank National Marine Sanctuary region, Gulf of Maine (Northwest Atlantic).

Burrowing cerianthid anemones (Cerianthus spp.) occur in mud, gravelly mud, and muddy gravel in the Gulf of Maine.  The non-retractable anemone tubes commonly extend 15 cm above the seabed, form dense aggregations (up to 10's m^-2), and provide habitat for Acadian redfish (Sebastes fasciatus).  Video sampling shows that anemones are common in untrawlable areas such as the mud bases and the muddy tops of gravel banks but are less common than expected in heavily fished mud basins.  Video observations were conducted in August 2001 in two settings:  'gravel window' areas on mud basin floors where cobbles and boulders on the tops of gravel mounds are almost covered by mud; and the mud floor and mud to muddy gravel walls of a long narrow basin.  Video imagery shows trawling occurs predominantly in mud around the gravel windows and on the mud floor and lower walls of the narrow basin.  Video transects across these features ranged up to more than a kilometer in length.  Quantification of 20-meter seabed segments shows that trawling is least intense and anemones and redfish are most common on the gravel windows and on the muddy gravel middle and upper basin walls.  These observations suggest that either: (1) trawling on mud has modified the distribution of cerianthids by direct removal; (2) trawling has modified the mud seabed so cerianthid recruitment has declined significantly; (3) untrawled mud in open basins is not conducive to cerianthid recruitment.  Variations in the distribution of cerianthids may have important implications for the successful recruitment of redfish.

WAKEFIELD, W.W. (Waldo.Wakefield@noaa.gov); NOAA National Marine Fisheries Service, Northwest Fisheries Science Center, Newport, OR.  Fisheries habitat studies: combining high-resolution physical and biological data.

Traditionally, estimates of the distribution and abundance of exploited species and their associated habitats are based on fishery-dependent sampling of the catch and fishery-independent survey data using fishing gears such trawls or a variety of fixed gears.  These data are often collected with individual samples that integrate over a scale of kilometers, compiled at a large geographic scale, and extrapolated to an overall estimate of stock size.  Considerations of the non-extractive effects of fishing on habitat were extremely limited.  Within the past fifteen years, a number of collaborations have developed between fisheries scientists and marine geologists hallmarked by an integration of sonar mapping of the seafloor with ground-truthing, and direct observation and enumeration of fish and invertebrate populations in the context of their seafloor habitat.  The challenge now is to efficiently relate small-scale observations and assessments of animal-habitat associations to the large geographic scales on which fisheries operate.  Much of the seafloor of the continental shelf and slope within regions of the U.S. EEZ has yet to be mapped and characterized. Large-scale seafloor habitat characterization is critical to the accurate assessment of fish stocks on a spatial scale pertinent to fisheries and those physical, biological and anthropological (e.g., fishing gear impacts) processes that influence them. We are now entering into a new phase of research into the ecosystems of these populations that will integrate state-of-the-art means for mapping marine habitats  (acoustical and optical systems, and accurately navigated platforms) with ecological data on fish distribution and abundance.  Examples of several recent and ongoing interdisciplinary studies, combining high-resolution physical and biological data sets will be discussed.

WALLACE, D. H. (dhwallace@aol.com)*¹ and T.B. HOFF²;  ¹Wallace & Associates, Cambridge, MD, ²Mid Atlantic Fisheries Management Council, Dover, DE.  Use of hydraulic clam dredges on benthic habitat off the Northeastern United States.

Hydraulic clam dredges have been used on the East Coast of the United States since World War II.  This equipment has evolved over time from marginally effective and habitat damaging to a highly effective type of fishing gear.  Improved design has minimized the effect on the habitat.  Natural events have more effect on the benthic community than this type of fishing gear since all of the fishing activity takes place in shallow water in sandy sediment.  The Chiarella et al. paper (in this workshop) on the Northeast US Gear Effects Workshop concluded that hydraulic clam dredges were not a major concern relative to otter trawls and scallop dredges.  The Mid-Atlantic FMC concurred with the conclusions of that workshop and acknowledged that hydraulic clam dredges could have an adverse effect on EFH if fished improperly or in the wrong sediment type.  The Council concluded that only a small amount (about 100 square miles) of fairly widespread homogeneous sandy bottom was fished annually and that any EFH impacts would be short-term.   However, the Council did evaluate seven scenarios that would close various important sections of the ocean to clam gear before they concluded that at this time there was no justification for any management measures for this gear.

WATLING, L. (watling@maine.edu)* and C. Skinder; Darling Marine Center, University of Maine, Walpole, ME.  Why fishing gear impact studies don't tell us what we need to know.

The late 1990s saw several comprehensive reviews of the impact of mobile fishing gear on benthic communities published in the scientific literature.  In particular, the review of Auster and Langton offered several tables detailing the results of individual studies.  We have updated this review and examined the studies for their predictive value.  That is, we ask, can the studies that have been done be used in very different geographic areas, or in unexamined habitats, to assess potential impacts of mobile fishing gear?  We suggest that most of the studies conducted to date are very good at telling us what has happened, but will give limited or inaccurate information about what will happen, or perhaps has happened in an unstudied area.  The lack of predictive capability of most studies results from the fact that they have relied on an examination of spatial patterns rather than understanding the underlying processes which result in the benthic community structure observed.  In some studies it has been concluded that fishing gear will have no measurable impact in some habitats.  In this paper we take a first principles approach and argue that were certain variables measured, such as sediment food quality, and were the studies done at the appropriate scale, impacts that were missed would have been seen.  Changing the way trawling studies are conducted will offer greater potential for predictive capability.

WATLING, L. (watling@maine.edu)* and A. PUGH; Darling Marine Center, University of Maine, Walpole, ME.  Reduction of species diversity in a cobble habitat subject to long-term fishing acitivity.

Studies dealing with the impact of mobile fishing gear have, for the most part, been conducted in areas with low fishing disturbance and are conducted using the BACI design.  There have only been a few studies where bottoms that have been fisihed routinely are compared with neighboring unfished areas.  We examined an area in 100 m water in the Gulf of Maine that had been fished with otter trawls for white hake and compared the epifaunal community with that of an adjacent area that was too rough for fishing even with rock-hopper gear.  In both areas, boulders with relatively flat surfaces were chosen for scraping and suction-sampling with an ROV.  There were far more species at the untrawled site as compared with the trawled site.  All other measures of diversity, including species-area curves, showed a reduction in diversity at the trawled site of about 50%.  Cluster analysis showed almost no similarity between the two sites.  For the most part, the presence of large, tree-like hydroids and bryozoans, present at the unfished site and absent at the fished site, provided additional habitat for many of the smaller invertebrates sampled.

WEST, T.L. (west@mail.ecu.edu)*¹, D.R. CORBETT², L.M. CLOUGH¹, M.W. CALFEE³, and J.E. FRANK²;  ¹Department of Biology, East Carolina University, Greenville, NC, ²Department of Geology, East Carolina University, Greenville, NC, ³Coastal Resource Management Program, East Carolina University, Greenville, NC.  Impacts of trawling and wind disturbance on water column processes in the Pamlico River Estuary, North Carolina.

Comparatively little attention has been given to the indirect impacts of bottom trawling in soft bottom ecosystems. Our study assesses the relative effects of bottom trawling and wind disturbance on water column nutrient  (NH₄, NO₃-NO₂, PO₄) loading and primary productivity (chlorophyll a concentration, bacterial abundance) in concert with measurements of sediment resuspension and transport (Frank, et al.).  We are working in South Creek, a subtributary of the Pamlico River Estuary, NC (USA) that has been closed to trawling for 15 years, and is characterized by large surface area, shallow depth, and wind-driven tides.  Trawling experiments in July and October 2001(repeated in 2002) were carried out during two different wind regimes: (a) days of consistent wind direction interrupted by an abrupt 180^o shift in direction (July); and (b) continuously shifting wind speed and direction (October). Two replicate areas, each containing a trawled and an untrawled site ~100,000 m², were sampled for 4 days prior to, and immediately after a trawling event. We were unable to detect a significant difference in any water column parameter (oxygen, nutrients or chlorophyll a) that could be attributed exclusively to trawling. Instead, changes appear to be driven by a variable wind regime.  Interestingly, measures of photosynthetic active radiation indicate that 60-80% of incident light is absorbed within the upper 0.5m of the water column.  These findings imply that South Creek and physically similar regions of the Pamlico River Estuary are light-limited systems in which wind-forced mixing events are primarily responsible for sediment resuspension from the benthos.

WILEN, J. E. (wilen@primal.ucdavis.edu); Department of Agricultural and Resource Economics, University of California, Davis, CA. Impacts of marine reserves: how fishermen behavior matters.

By a wide margin, most of what we think we know about the impacts of marine reserves on fisheries has been derived by analytical and simulation modeling rather than with hard empirical evidence.  Most of that analytical modeling, in turn, has been done by biologists, focusing on aspects of the system with which they are most familiar, namely biological mechanisms.  The most important findings derived from biological modeling of marine reserves are that dispersal mechanisms are critical to the kinds and magnitudes of impacts of closed areas.  These findings have largely been derived from models that make simplifying assumptions about fishing mortality.  This paper argues that the spatial distribution of fishing mortality is as important as biological dispersal mechanisms to the ultimate impact of reserves.  Moreover, the spatial distribution of fishing effort is determined by economically motivated decisions not typically considered by biological modelers.  We predict, using data from the Northern California red sea urchin fishery, how the distribution of effort is likely to change in response to closed areas, and how that behavioral response is important to the ultimate impacts of closed areas.  We argue that failure to account for the economic determinants of fishing effort bias conclusions about reserves, and we discuss the nature of those biases.

WILLIAMS, A. (alan.williams@csiro.au)*, B. BARKER, R.J. KLOSER, N.J. BAX and A.J. BUTLER; CSIRO Marine Research, Hobart, Tasmania, Australia.  Structure and use of a continental slope seascape: insights for the fishing industry and marine resource managers.

Benthic habitats of the upper continental slope seabed (~300-700 m depth) off SE Australia are being surveyed for the first time in response to the needs of regional, ecosystem-based, marine management plans being developed under Australia's Oceans Policy, and increased commercial fishery reliance on fishes that inhabit the slope seascape. We developed substratum maps of the Big Horseshoe Canyon - one of the region's prime fishing grounds - using multi-beam acoustic backscatter data, and target-sampled with video cameras and a range of physical samplers. In upper-slope depths, a patchy mosaic of habitats is formed of sloping terraces of muddy substrata and rubble patches that support a sparse benthic epifauna, together with low-relief rocky ridges formed by outcropping claystones and limestones that support communities of erect epifauna dominated by sponges.  Many sedentary adult individuals of two key commercial species (pink ling and ocean perch) shelter in a range of microhabitats provided only by the rocky habitats. Video shows that bottom trawls 'hook-up' on rocky substratum, turning and moving loose pieces - an observation acknowledged by commercial fishermen who also report that boulders and 'slabs' are removed and redistributed. This is evidence of a fishing impact that is, at least in part, irreversible. The question then is, how much impact will adversely affect long-term fishery productivity and conservation values? We discuss this question with respect to managers needs for both the detailed understanding and fine-scale mapping of habitats provided by scientific survey, and the fishing industry's knowledge of broad-scale habitat distributions that enables extrapolation to a regional fishery scale.

WILSON, C. (cwilson@lsu.edu)*, H. ROBERTS, Y. ALLEN, and J. SUPAN; Oyster Geophysics Program, Department of Oceanography and Coastal Sciences, SC&E, Louisiana State University, Baton Rouge, LA.  The use of field calibrated side-scan acoustic reflectance patterns to quantify and track alterations to benthic habitat associated with Louisiana's oyster industry.

Coastal Louisiana, like many deltaic land masses, faces continued landscape alteration from natural processes and anthropogenic impacts that affect estuarine habitat. The most promising steps to slow/mitigate these changes are river diversions that introduce freshwater and sediment to river-flanking environments and to help establish ideal salinities over historic oyster grounds.  Critical to the success of these programs is a rapid and accurate means to qualify and quantify changes in oyster habitat.  Digital high-resolution acoustic instrumentation linked to modern data acquisition and processing software was used to build baseline of information for evaluating future changes in shallow water bottoms, with special emphasis on oyster habitats. Application of digital side-scan sonar (100 and 500 kHz), a broad-spectrum sub-bottom profiler (4-24 kHz) for rapidly acquiring water column, surficial and shallow subsurface was used to map over 10,000 ha of water bottom. Geo-referenced side scan sonar mosaics were incorporated into a GIS data base.  These data sets, "calibrated" with surface sampling, coring, and other "ground truthing" have established that numerically indexed acoustic reflectance intensities correlate closely with surface shell and oyster reef density.  With image processing techniques to analyze mosaic reflectance patterns, we estimated the percent and total acreage of several bottom types.

WITHERELL, D. (David.Witherell@noaa.gov)* and C. COON; North Pacific Fishery Management Council, Anchorage, AK.  Approach to evaluating fishing effects on EFH off Alaska.

The North Pacific Fishery Management Council is in the process of evaluating fisheries for adverse effects on essential fish habitat, and over the coming year, will be considering additional measures to minimize these effects to the extent practicable.  The steps used in the evaluation include 1) description of the fisheries, 2) distribution and intensity of the fisheries, 3) description of the habitat effected, 4) summary of scientific studies applicable to each fishery, and finally, 5) evaluation of each fishery to see if effects on habitat are more than minimal and more than temporary in nature.   For each of the principal fisheries managed under federal fishery management plans, we first described the gear used, fishing methods, and habitats potentially impacted (including living substrates and prey species).  We then mapped the distribution and intensity of fishing effort in each fishery, and compared this with available information on benthic habitats to determine the extent of effects. Using this information, along with the literature on fishing gear impacts, the fisheries will be evaluated against criteria for determining adverse effects. For those fisheries having adverse effects, management measures will be proposed to minimize effects to the extent practicable.  Management measures will also be proposed to mitigate cumulative effects of fisheries, and may be proposed to reduce effects of fisheries that have not been determined to have significant adverse effects on fish habitat.  The fishery evaluation and identification of potential management measures will be completed by October 2002. The poster reviews the fishery evaluation process and development of alternatives to minimize adverse effects of fisheries on essential fish habitat off Alaska.

ZWANENBURG. K.C.T. (zwanenburgk@mar.dfo-mpo.gc.ca)*, M. SHOWELL, and S. WILSON; Marine Fish Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada.  Ecological footprints of Scotian Shelf groundfish fisheries.

We examine by-catch (non-directed catch) of commercial and non-commercial demersal fish species for a number of Scotian Shelf fisheries over the past two decades to determine their relative impacts. Although by-catch of commercial species is readily available (landings), by-catch of non-commercial species exists for only a small subset of fisheries. Landings data give conservative estimates of fishery impacts because they record only commercial species, while observing catches is costly but estimates non-commercial by-catch. We compare impacts of fisheries as derived from landings and on-board observer data. The impacts are cast as ecological footprints with the number of by-catch species defining breadth and the rates of by-catch defining depth of the footprints. From landings data, the proportions (by weight) caught as directed catch ranges from less than 1% (narrow footprints) to as high as 100% (broad footprints) while by-catch rates in these same fisheries range from near 0% (shallow footprints) to near 100% (deep footprints).  True breadth and depth (in species space) of ecological footprints can; however, only be derived from observed catches. These are available for only a small subset of fisheries. The Atlantic halibut (Hippoglossus hippoglossus) fishery catches 40 additional species with 13 at a rate of 1% or more of the total halibut caught. These analyses provide a classificatory framework useful for allocating additional investigative efforts to particular fisheries with broad or deep footprints. Long-term impacts of by-catches can also be estimated by hindcasting the potential cumulative impacts of fisheries based on current by-catch profiles.

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