[Federal Register: October 21, 2003 (Volume 68, Number 203)]
[Notices]
[Page 60086-60091]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21oc03-45]
[[Page 60086]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[I.D. 092203D]
Small Takes of Marine Mammals Incidental to Specified Activities;
Oceanographic Surveys in the Southeast Caribbean Sea and Adjacent
Atlantic Ocean
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of receipt of application and proposed incidental take
authorization; request for comments.
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SUMMARY: NMFS has received an application from the Lamont-Doherty Earth
Observatory (LDEO), a part of Columbia University, for an Incidental
Harassment Authorization (IHA) to take small numbers of marine mammals,
by harassment, incidental to conducting oceanographic surveys in the
Southeast Caribbean Sea and adjacent Atlantic Ocean. Under the Marine
Mammal Protection Act (MMPA), NMFS is requesting comments on its
proposal to issue an authorization to LDEO to incidentally take, by
harassment, small numbers of several species of cetaceans and pinnipeds
for a limited period of time within the next year.
DATES: Comments and information must be received no later than November
20, 2003.
ADDRESSES: Comments on the application should be addressed to the
Acting Chief, Marine Mammal Conservation Division, Office of Protected
Resources, National Marine Fisheries Service, 1315 East-West Highway,
Silver Spring, MD 20910-3225, or by telephoning the contact listed
here. A copy of the application containing a list of the references
used in this document may be obtained by writing to this address or by
telephoning the contact listed here. Comments cannot be accepted if
submitted via e-mail or the Internet.
FOR FURTHER INFORMATION CONTACT: Kimberly Skrupky, Office of Protected
Resources, NMFS, (301) 713-2322, ext 163.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct the Secretary of Commerce to allow, upon request, the
incidental, but not intentional, taking of marine mammals by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified geographical region if certain findings are
made and either regulations are issued or, if the taking is limited to
harassment, a notice of a proposed authorization is provided to the
public for review.
Permission may be granted if NMFS finds that the taking will have a
negligible impact on the species or stock(s) and will not have an
unmitigable adverse impact on the availability of the species or
stock(s) for subsistence uses and that the permissible methods of
taking and requirements pertaining to the monitoring and reporting of
such takings are set forth. NMFS has defined ``negligible impact'' in
50 CFR 216.103 as ``...an impact resulting from the specified activity
that cannot be reasonably expected to, and is not reasonably likely to,
adversely affect the species or stock through effects on annual rates
of recruitment or survival.''
Section 101(a)(5)(D) of the MMPA established an expedited process
by which citizens of the United States can apply for an authorization
to incidentally take small numbers of marine mammals by harassment.
Under section 3(18)(A), the MMPA defines ``harassment'' as:
any act of pursuit, torment, or annoyance which (i) has the
potential to injure a marine mammal or marine mammal stock in the
wild; or (ii) has the potential to disturb a marine mammal or marine
mammal stock in the wild by causing disruption of behavioral
patterns, including, but not limited to, migration, breathing,
nursing, breeding, feeding, or sheltering.
The term ``Level A harassment'' means harassment described in
subparagraph (A)(i). The term ``Level B harassment'' means harassment
described in subparagraph (A)(ii).
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS
review of an application followed by a 30-day public notice and comment
period on any proposed authorizations for the incidental harassment of
marine mammals. Within 45 days of the close of the comment period, NMFS
must either issue or deny issuance of the authorization.
Summary of Request
On August 7, 2003, NMFS received an application from LDEO for the
taking, by harassment, of several species of marine mammals incidental
to conducting a seismic survey program. As presently scheduled, a
seismic survey will be conducted in the Southeast Caribbean Sea and
Adjacent Atlantic Ocean. The Southeast Caribbean Sea and Atlantic Ocean
cruise will be off the coast of Venezuela in an area extending from
59[deg] to 71[deg] W and 10[deg] to 15[deg] N from January 11, 2004 to
February 21, 2004. The operations will partly take place in the
Exclusive Economic Zones (EEZ) of several nations in the Southeast
Caribbean (including Venezuela, Aruba, Bonaire, Curacao, Trinidad, and
Tobago) as well as in international waters.
The purpose of the project is to obtain information on island arc
movements and geometry which can be used to better understand the
history and mechanical processes by which island arcs accrete to
continents, deeply buried rocks are exhumed, and folded belts and
different types of sedimentary basins form along oblique collision
zones. The interplay of the crust and subcrustal lithosphere during arc
accretion and metamorphic belt exhumation and subduction polarity
reverses will be examined. In addition, the flow patterns of the
sublithospheric mantle beneath the plate boundary and northern South
America as a whole and beneath the right lateral shear zone between
them will be examined.
Description of the Activity
The seismic survey will involve two vessels which will conduct the
seismic work. The source vessel, the R/V Maurice Ewing, will deploy an
array of 20 airguns as an energy source, plus a 6-km (3.2 n.mi.) towed
hydrophone streamer. A second vessel, the R/V Seward Johnson, will
deploy and retrieve Ocean Bottom Seismometers (OBSs). As the airgun
array is towed along the survey line, the towed hydrophone streamer or
OBSs will receive the returning acoustic signals and transfer the data
to the on-board processing system. Water depths within the study area
range from approximately 15-6,000 m (49-19,685 ft). Most of the survey
effort will take place in waters greater than 1,000 m (3,281 ft) deep,
2,031 km (1,097 n.mi.) will be surveyed in water depth ranging from
100-1,000 m (328-3,281 ft) deep, and a small portion of the survey
effort will occur in shallow water less than 100 m (328 ft) deep.
The procedures to be used for the seismic study will be similar to
those used during previous seismic surveys by LDEO in the equatorial
Pacific Ocean (Carbotte et al., 1998, 2000). The proposed seismic
surveys will use conventional seismic methodology with a towed airgun
array as the energy source, and a towed hydrophone streamer and/or OBSs
as the receiver system. The OBSs will be deployed by the Seward
Johnson. The energy to the airgun array is compressed air supplied
[[Page 60087]]
by compressors on board the source vessel. In addition to the
operations of the airgun array, a multibeam bathymetric sonar will be
operated from the source vessel continuously throughout the entire
cruise, and a lower-energy sub-bottom profiler will also be operated
during most of the survey.
The Seward Johnson will have four deployments of OBSs, prior to the
time when the Maurice Ewing conducts airgun operations in that area.
After each line is shot, the Seward Johnson will retrieve the OBSs,
download the data, and refurbish the units before redeploying the OBSs
along the next line that will be shot. During the Southeast Caribbean
cruise, there will be four deployments of OBSs, one deployment along
each of the OBS lines. OBSs will also be deployed at two other
locations near each line to fill data gaps between islands.
In addition, the ocean floor will be mapped with an Atlas
Hydrosweep DS-2 multibeam 15.5-kHz bathymetric sonar, and a 3.5-kHz
sub-bottom profiler will also be operated along with the multibeam
sonar. Both of these sound sources will be operated simultaneously with
the airgun array. For more information regarding the Atlas Hydrosweep
DS-2 multibeam bathymetric sonar, please refer to previous Federal
Register Notices (68 FR 44291, July 28, 2003, and 68 FR 17773, April
11, 2003).
During the airgun operations, the vessel will travel at 7.4-9.3 km/
hr (4-5 knots), and seismic pulses will be emitted at intervals of 60-
90 sec (OBS lines) and approximately 20 sec (MCS lines). The 20 sec
spacing corresponds to a shot interval of about 50 m (164 ft). The 60-
90 sec spacing along OBS lines is to minimize reverberation from
previous shot noise during OBS data acquisition, and the exact spacing
will depend on water depth. The 20-airgun array will include airguns
ranging in chamber volume from 80 to 850 in3. These airguns will be
spaced in an approximate rectangle of dimensions of 35 m (115 ft)
across track by 9 m (30 ft) along track.
Along the selected lines, the OBSs will be positioned by the Seward
Johnson prior to the time when the Maurice Ewing conducts airgun
operations in that area. After each line is shot, the Seward Johnson
will retrieve the OBSs, download the data, and refurbish the units
before redeploying the OBSs along the next line that will be shot.
During the Southeast Caribbean cruse, there will be four deployments of
OBSs, one deployment along each of the OBS lines. OBSs will also be
deployed at two other locations near each line to fill data gaps
between islands.
When airgun operations with the 20-gun array commence after a
period without airgun operations, the number of guns firing will be
increased gradually (``ramped up,'' also described as a ``soft
start''). Operations will begin with the smallest gun in the array (80
in\3\). Guns will be added in sequence such that the source level of
the array will increase in steps not exceeding 6 dB per 5-min period
over a total duration of approximately 25 minutes. Throughout the ramp-
up procedure, the safety zone for the full 20-gun array will be
maintained. Given the presence of the streamer and airgun array behind
the vessel, the turning rate of the vessel with trailing streamer and
array is no more than five degrees per minute, limiting the
maneuverability of the vessel during operations.
Along with the airgun operations, two additional acoustical data
acquisition systems will be operated during most or all of the cruise.
The ocean floor will be mapped with an Atlas Hydrosweep DS-2 multibeam
15.5-kHz bathymetric sonar, and a 3.5-kHz sub-bottom profiler will also
be operated along with the multibeam sonar. These sound sources are
commonly operated from the Maurice Ewing simultaneous with the airgun
array.
The Atlas Hydrosweep is mounted on the hull of the Maurice Ewing,
and it operates in three modes, depending on the water depth. There is
one shallow water mode and there are two deep-water modes: an Omni mode
and a Rotational Directional Transmission mode (RDT). When water depth
is less than 400 m (1312.3 ft), the source output is 210 dB re 1
microPa m rms and a single 1-millisec pulse or ``ping'' per second is
transmitted, with a beamwidth of 2.67 degrees fore-aft and 90 degrees
athwartship. The beamwidth is measured to the -3 dB point, as is
usually quoted for sonars. The Omni mode is identical to the shallow-
water mode except that the source output is 220 dB rms. The Omni mode
is normally used only during start up. The RDT mode is normally used
during deep-water operation and has a 237 dB rms source output. In the
RDT mode, each ``ping'' consists of five successive transmissions, each
ensonifying a beam that extends 2.67 degrees fore-aft and approximately
30 degrees in the cross-track direction. The five successive
transmissions (segments) sweep from port to starboard with minor
overlap, spanning and overall cross-track angular extent of about 140
degrees, with small gaps between the pulses for successive 30-degree
segments. The total during of the ``ping,'' including all five
successive segments, varies with water depth, but is 1 millisec in
water depths less than 500 m (1640.5 ft) and 10 millisec in the deepest
water. For each segment, ``ping'' duration is 1/5th of these values or
2/5th for a receiver in the overlap area ensonified by two beam
segments. The ``ping'' interval during RDT operations depends on water
depth and varies from once per second in less than 500 m (1640.5 ft)
water depth to once per 15 seconds in the deepest water.
The sub-bottom profiler is normally operated to provide information
about the sedimentary features and the bottom topography that is
simultaneously being mapped by the Hydrosweep. The energy from the sub-
bottom profiler is directed downward by a 3.5 kHz transducer mounted in
the hull of the Maurice Ewing. The output varies with water depth from
50 watts in shallow water to 800 watts in deep water. Pulse interval is
1 second but a common mode of operation is to broadcast five pulses at
1-s intervals followed by a 5-s pause.
Additional information on the airgun arrays, bathymetric sonars,
and sub-bottom profiler specifications is contained in the application,
which is available upon request (see ADDRESSES).
Description of Habitat and Marine Mammals Affected by the Activity
A detailed description of the Southeast Caribbean Sea and its
associated marine mammals can be found in a number of documents
referenced in the LDEO application as well as in the LDEO application
itself, and is not repeated here. In the Southeast Caribbean Sea and
adjacent Atlantic Ocean, 30 marine mammal species are known to occur
within the proposed study areas. Six species are listed as endangered
under the U.S. Endangered Species Act (ESA): sperm, humpback, sei, fin,
and blue whales, as well as West Indian manatees. These species
included in this application are the sperm whale (Physeter
macrocephalus), pygmy sperm whale (Kogia breviceps), dwarf sperm whale
(Kogia sima), Cuvier's beaked whale (Ziphius cavirostris), Gervais'
beaked whale (Mesoplodon europaeus), Blainville's beaked whale
(Mesoplodon densirostris), rough-toothed dolphin (Steno bredanensis),
tucuxi (Sotalia uviatilis), bottlenose dolphin (Tursiops truncatus),
Pantropical spotted dolphin (Stenella attenuata), Atlantic spotted
dolphin (Stenella frontalis), spinner dolphin (Stenella longirostris),
clymene dolphin (Stenella clymene), striped dolphin (Stenella
coeruleoalba), long-beaked common dolphin (Delphinus capensis),
Fraser's dolphin
[[Page 60088]]
(Lagenodelphis hosei), Risso's dolphin (Grampus griseus), melon-headed
whale (Peponocephala electra), pygmy killer whale (Feresa attenuata),
false killer whale (Pseudorca crassidens), killer whale (Orcinus orca),
short-finned pilot whale (Globicephala macrorhynchus), humpback whale
(Megaptera novaeangliae), minke whale (Balaenoptera acutorostrata),
Bryde's whale (Balaenoptera edeni), sei whale (Balaenoptera borealis),
fin whale (Balaenoptera physalus), and blue whale (Balaenoptera
musculus). Also, one species of pinniped could potentially be
encountered during the proposed seismic surveys. This includes the
hooded seal (Cystophora cristata). Additional information on most of
these species is available at: http://www.nmfs.noaa.gov/prot_res/PR2/Stock_Assessment_Program/sars.html
.
Potential Effects on Marine Mammals
The sound pressure fields for the 20-gun arrays has been modeled by
LDEO, in relation to distance and direction from the airguns. Table 1
in the application (LDEO Caribbean 2003) shows the distances from the
arrays where sound levels of [gteqt]190, 180, 170, and 160 dB re 1
microPa (rms) are predicted to be received:
----------------------------------------------------------------------------------------------------------------
Predicted RMS Radii in meters/ft
Airgun Array ---------------------------------------------------------------
190 dB 180 dB 170 dB 160 dB
----------------------------------------------------------------------------------------------------------------
20 airguns...................................... 275/902 900/2953 2600/8531 9000/29,529
----------------------------------------------------------------------------------------------------------------
The rms (root-mean-squared) pressure is an average over the pulse
duration. The rms level of a seismic pulse is typically about 10 dB
less than its peak level (Greene 1997; McCauley et al. 1998, 2000a).
The safety radii will be verified prior to the Southeast Caribbean
cruise, using data from an acoustical measurement study in deep water
within the Gulf of Mexico, which took place from 27 May to 3 June 2003.
The data will either confirm or be used to refine the safety radii to
be used during this and future LDEO seismic studies.
Previous applications from LDEO have described similar actions.
Past Federal Register notices for LDEO include July 28, 2003 (68 FR
44291), August 26, 2003 (68 FR 51240), September 12, 2003 (68 FR
53714), and September 17, 2003 (68 FR 54421). The Federal Register
notice on April 14, 2003 (68 FR 17909) describes, in detail, the
characteristics of the Ewing's acoustic sources and, in general, the
anticipated effects on marine mammals including masking, disturbance,
and potential hearing impairment and other physical effects. Possible
effects of the sub-bottom profiler have been used in the projects
described in the above notices. The LDEO Southeast Caribbean
application also provides information on what is known about the
effects on marine mammals of the types of seismic operations planned by
LDEO.
Possible Effects of the Mid-Frequency Sonar Signals
A multibeam bathymetric sonar (Atlas Hydrosweep DS-2, 15.5-kHz)
will be operated from a source vessel at some times during the planned
study. Sounds from the multibeam sonar are very short pulses, occurring
for 1-10 msec once every 1 to 15 sec, depending on water depth. Most of
the energy in the sound pulses emitted by this multibeam sonar is at
high frequencies, centered at 15.5 kHz. The beam is narrow (2.67[deg])
in fore-aft extent, and wide (140[deg]) in the cross-track angles. A
marine mammal at depth near the trackline would be in the main beam for
only one or two of the five segments. Further information on mid-
frequency sonar can be found in the application or in a previous
Federal Register notice 68 FR 17909 (April 14, 2003).
Possible Effects of the Sub-bottom Profiler Signals
Sound levels have not been measured for the sub-bottom profiler
used by the Maurice Ewing, but Burgess and Lawson (2000) measured the
sounds propagating more or less horizontally from a similar unit with
similar source output (205 dB re 1 microPa-m). The 160 and 180 dB re 1
microPa (rms) radii, in the horizontal direction, were estimated to be
near 20 m (66 ft) and 8 m (26 ft), respectively, from the source, as
measured in 13 m (43 ft) water depth. The corresponding distances for
an animal in the beam below the transducer would be greater, on the
order of 180 m (591 ft) and 18 m (59 ft), assuming spherical spreading.
Further information on the sub-bottom profiler can be found in the
application as well as in a previous Federal Register notice (68 FR
44291, July 28, 2003).
Estimates of Take by Harassment for the Southeast Caribbean Sea Cruise
All anticipated takes by harassment involve a temporary change in
behavior. The mitigation measures to be applied will minimize the
possibility of injurious takes. LDEO has calculated the ``best
estimates'' for the numbers of animals that could be taken by level B
harassment during the proposed seismic survey in the SE Caribbean Sea
using data on marine mammal abundance from a previous survey region, as
shown in the predicted RMS radii table.
These estimates are based on a consideration of the number of
marine mammals that might be exposed to sound levels greater than 160
dB, which is currently used as the criterion for the onset of level B
harassment, by operations with the 20-gun array planned to be used for
the project. The anticipated radius of influence of the multibeam sonar
is less than that for the airgun array. It is assumed that any marine
mammals close enough to be affected by the multibeam sonar would
already be affected by the airguns. Therefore, no additional allowance
is included for animals that might be affected by the multibeam sonar.
Tables 4 and 5 in the application explain the corrected density
estimates as well as the ``best estimate'' of the numbers of each
species that would be exposed to seismic sounds greater than 160 dB.
According to the tables, the percentages of delphinidae that might
be exposed to sound levels greater than 160 dB range from zero to 4.4
percent. Aside from the sperm whale, the physeterida and ziphiidae
exposure percentages are zero. The percent of sperm whales that might
be exposed is 0.4 percent. Except for the humpback and blue whales, the
mysticetes and pinnipeds percent of exposure is zero. It is estimated
that 1.7 percent of humpback whales and 1.0 percent of blue whales
could be exposed to sound levels greater than 160 dB. The ``best
estimate'' of the numbers of common, bottlenose, Atlantic spotted, and
pantropical spotted dolphins that might be harassed (exposed to levels
greater than 160 dB) are 1.9 percent, 4.4 percent, 2.6 percent, and 4.3
percent, respectively.
The 160 dB criterion is based on studies of baleen whales.
Odontocete hearing at low frequencies is relatively insensitive and
delphinids generally
[[Page 60089]]
appear to be more tolerant of strong low-frequency sounds than are most
baleen whales. As a result, significantly fewer odontocetes than
estimated here are likely to be harassed by the proposed action.
Pinnipeds are not expected to be encountered in the SE Caribbean
Sea and so the ``best estimate'' of the number that might be affected
is zero. Although unlikely, a more conservative estimate of a maximum
of five pinnipeds (most likely hooded seals) might be affected by a
portion of the proposed survey in the SE Caribbean Sea. For further
information regarding the estimated takes, refer to the LDEO Caribbean
2003 application.
Conclusions- Effects on Cetaceans
Strong avoidance reactions by several species of mysticetes to
seismic vessels have been observed at ranges up to 8 km (4.3 nm) and
occasionally as far as 30 km (16.2 nm) from the source vessel. Some
bowhead whales avoided waters within 30 km (16.2 nm) of the seismic
operation. However, reactions at such long distances appear to be
atypical of other species of mysticetes and, even for bowheads, may
only apply during migration.
Odontocete reactions to seismic pulses, or at least those of
dolphins, are expected to extend to lesser distances than are those of
mysticetes. Odontocete low-frequency hearing is less sensitive than
that of mysticetes, and dolphins are often seen from seismic vessels.
There are documented instances of dolphins approaching active seismic
vessels. However, dolphins as well as some other types of odontocetes
sometimes show avoidance responses and/or other changes in behavior
when near operating seismic vessels.
Taking account of the mitigation measures that are planned, effects
on cetaceans are generally expected to be limited to avoidance of the
area around the seismic operation and short-term changes in behavior,
falling within the MMPA definition of ``Level B harassment.'' In the
cases of mysticetes, these reactions are expected to involve small
numbers of individual cetaceans. The ``best estimate'' is that 377
humpback whales or about 1.7 percent of the North and South Atlantic
populations will be exposed to sound levels greater than or equal to
160 dB re 1 microPa (rms). Acevedo and Smultea (1995) provide evidence
that the North and South Atlantic populations overlap in their
wintering areas. Similarly, only 52 sperm whales or approximately 0.4
percent of the North Atlantic sperm whale population would receive
seismic sounds greater than or equal to 160 dB during the proposed
survey in the SE Caribbean Sea.
The numbers of odontocetes that may be harassed by the proposed
activities are small relative to the population sizes. A maximum of
2475, 2222, 1369, 867, and 564 common, bottlenose, Atlantic spotted,
rough toothed, and pantropical spotted dolphins, respectively (the most
abundant delphinids in the proposed survey area) are expected to be
exposed to seismic sounds greater than or equal to 160 dB. This
represents 1.9 to 4.4 percent of the North Atlantic populations of
these species based on population estimates for these species. However,
these dolphin species surveys have not been conducted for most of their
range in the North Atlantic Ocean and adjacent waters. The true
percentages of the populations that might be exposed to seismic sounds
greater than or equal to 160 dB are much less than 1.9-4.4 percent. The
population sizes and the 1.9 to 4.4 percent are based on a small
fraction of their range and their actual population sizes are actually
much larger. The true percentages of the populations that might be
exposed to seismic sounds greater than 160 dB are therefore much less
than 1.9 to 4.4 percent. In light of all of these factors, the
potential takings by Level B harassment are expected to have no more
than a negligible impact on the affected species or stocks.
Mitigation measures such as controlled speed, course alteration,
look-outs, non-pursuit, ramp-ups, and power-downs when marine mammals
are seen within defined ranges (See Mitigation) should further reduce
short-term reactions to disturbance, and minimize any effects on
hearing sensitivity.
Conclusions- Effects on Pinnipeds
Pinnipeds are not expected to be encountered during the proposed
seismic survey in the SE Caribbean Sea. However, a more conservative
estimate of a maximum of 5 pinnipeds may be affected by a portion of
the proposed survey in the SE Caribbean Sea if they were encountered.
If pinnipeds were encountered, the proposed seismic survey would have,
at most, a short-term effect on their behavior and negligible impacts
on the affected populations. Responses of pinnipeds to acoustic
disturbance are variable, but usually quite limited. Effects are
expected to be limited to short-term and localized behavioral changes
falling within the MMPA definition of ``Level B harassment.''
Mitigation
Vessel-based observers will monitor marine mammals in the vicinity
of the arrays. LDEO proposes to power-down the airguns if marine
mammals are observed within the proposed safety radii, which will be
verified prior to the southeast Caribbean cruise, using data from an
acoustical measurement study in the Gulf of Mexico which took place May
27, 2003, through June 3, 2003. Also, LDEO proposes to use a ramp-up
procedure when commencing operations using the 20-gun array. Ramp-up
will begin with the smallest gun in the array (80 in\3\), and guns will
be added in a sequence such that the source level of the array will
increase at a rate no greater than 6 dB per 5-minute period over a
total duration of about 25 minutes. Refer to LDEO's application for
more detailed information about the mitigation measures that are an
integral part of the planned activity.
Operational Mitigation
The directional nature of the 20-airgun array to be used in this
project is an important mitigating factor, resulting in lower sound
levels at any given horizontal distance than would be expected at that
distance if the source were omnidirectional with the stated nominal
source level. Because the actual seismic source is a distributed sound
source (20 guns) rather than a single point source, the highest sound
levels measurable at any location in the water will be less than the
nominal source level.
The airguns comprising these arrays will be spread out
horizontally, so that the energy from the arrays will be directed
mostly downward. This directionality will result in reduced sound
levels at any given horizontal distance than would be expected at that
distance if the source were omnidirectional with the nominal source
level.
Marine Mammal Monitoring
Vessel-based observers will monitor marine mammals near the seismic
source vessel during all daytime airgun operations and during any
nighttime start-ups of the airguns. During daylight, vessel-based
observers will watch for marine mammals near the seismic vessel during
periods with shooting (including ramp-ups), and for 30 minutes prior to
the planned start of airgun operations after an extended shut-down.
Observers will not be on duty during ongoing seismic operations at
night; bridge personnel will watch for marine mammals during this
period and will call for the airguns to be powered-
[[Page 60090]]
down if marine mammals are observed in or about to enter the safety
radii. If the airguns are ramped-up at night, two marine mammal
observers will monitor marine mammals near the source vessel for 30
minutes prior to ramp-up using night vision devices.
Proposed Safety Radii
Received sound levels have been modeled for the 20-gun arrays.
Based on the modeling, estimates of the 190-, 180-, 170- and 160-dB re
1 microPa (rms) distances for these arrays have been provided in the
application. Airgun operations will be powered-down (or shut-down)
immediately when cetaceans or pinnipeds are seen within or about to
enter the appropriate 180-dB (rms) or 190-dB (rms) safety radius,
respectively. These 180- and 190-dB criteria are consistent with
guidelines for onset of level A harassment of cetaceans and pinnipeds
by NMFS (2000) and other guidance by NMFS.
Mitigation During Operations
The following mitigation measures, as well as marine mammal
monitoring, will be adopted during the proposed Mid-Atlantic seismic
surveys, provided that doing so will not compromise operational safety
requirements: (1) Speed or course alteration; (2) power-down
procedures; (3) shut-down procedures; and (4) ramp-up procedures.
Airgun operations will be suspended when marine mammals are
observed within, or about to enter, designated safety zones, where
there is a possibility of Level A harassment.
Course Alteration
If a marine mammal is detected outside the appropriate safety
radius and, based on its position and the relative motion, is likely to
enter the safety radius, the vessel's speed and/or direct course will
be changed in a manner that also minimizes the effect to the planned
science objectives. The marine mammal activities and movements relative
to the seismic vessel will be closely monitored to ensure that the
marine mammal does not approach within the safety radius. If the mammal
appears likely to enter the safety radius, further mitigative actions
will be taken, i.e., either further course alterations or shutdown of
the airguns.
Power-down Procedures
If a marine mammal is detected outside the safety radius but is
likely to enter the safety radius, and if the vessel's course and/or
speed cannot be changed to avoid having the marine mammal enter the
safety radius, the airguns will be powered-down before the mammal is
within the safety radius. Likewise, if a mammal is already within the
safety zone when first detected, the airguns will be powered-down
immediately. For the power-down procedure for the 20-gun array, one 80
in\3\ airgun will be operated during the interruption of seismic
survey. Airgun activity (after both power-down and shut-down
procedures) will not resume until the marine mammal has cleared the
safety zone. An animal will be considered to have cleared the safety
zone if it is visually observed to have left the safety zone, or if it
has not been seen within the zone for 15 min (small odontocetes,
including delphinidae, and pinnipeds) or 30 min (mysticetes and large
odontocetes, including sperm, pygmy sperm, dwarf sperm, and beaked
whales).
Shut-down Procedures
If a marine mammal is detected close to the airgun array during a
power-down, modeled safety radii for a single gun will be maintained.
If the 20-gun array is used, the single gun that will be firing is 80
in3. Since no calibrations have been done to confirm the modeled safety
radii for this single gun, conservative (1.5 times the safety radius)
radii will be used: 54 m (177 ft) for cetaceans, and 20 m (66 ft) for
pinnipeds. If a marine mammal is seen within the appropriate safety
radius of the array when the air guns have already been powered-down,
airgun operations will be shut-down.
Ramp-up Procedure
A ``ramp-up'' procedure will be followed when the airgun arrays
begin operating after a specified duration without airgun operations.
Under normal operational conditions (vessel speed 4 knots, or 7.4 km/
hr), a ramp-up would be required after a power-down or shut-down period
lasting about 8 minutes or longer if the Ewing was towing the 20-gun
array. At 4 knots, the source vessel would travel 900 m (2953 ft)
during an 8-minute period. If the towing speed is reduced to 3 knots or
less, as sometimes required when maneuvering in shallow water, it is
proposed that a ramp-up would be required after a ``no shooting''
period lasting 10 minutes or longer. At towing speeds not exceeding 3
knots, the source vessel would travel no more than 900 m (3117 ft) in
10 minutes. Based on the same calculation, a ramp-up procedure would be
required after a 6 minute period if the speed of the source vessel was
5 knots.
Ramp-up will not occur if the safety radius has not been visible
for at least 30 min prior to the start of operations in either daylight
or nighttime. If the safety radius has not been visible for that 30
minute period (e.g., during darkness or fog), ramp-up will not commence
unless one airgun has been maintained during the interruption of
seismic activity.
Monitoring and Reporting
LDEO proposes to conduct the following marine mammal monitoring of
its 2003 SE Caribbean Sea seismic program.
Vessel-based Visual Monitoring
At least two observers will be based aboard the vessel. At least
one experienced marine mammal observer will be on duty aboard the
seismic vessel, and observers will be appointed by LDEO with NMFS
concurrence. Observers will be on duty in shifts of duration no longer
than 4 hours. The second observer will also be on watch part of the
time, including the 30-minute periods preceding startup of the airguns
and during ramp-ups. Use of two simultaneous observers will increase
the proportion of the marine mammals present near the source vessel
that are detected. LDEO bridge personnel additional to the dedicated
marine mammal observers will also assist in detecting marine mammals
and implementing mitigation requirements whenever possible (they will
be given instruction on how to do so), especially during operations at
night when designated observers will not be on duty.
The observer(s) will watch for marine mammals from the highest
practical vantage point on the vessel, which is either the bridge or
the flying bridge. On the bridge of the Maurice Ewing, the observer's
eye level will be 11 m (36 ft) above sea level, allowing for good
visibility within a 210[deg] arc. If observers are station on the
flying bridge, the eye level will be 14.4 m (47.2 ft) above sea level.
The observer(s) systematically scan the area around the vessel with
reticle binoculars (e.g., 7 X 50 Fujinon) and with the naked eye during
the daytime. At night, night vision equipment will be available (ITT
F500 Series Generation 3 binocular image intensifier or equivalent).
Laser rangefinding binoculars (Leica LRF 1200 laser rangefinder or
equivalent) will be available to assist with distance estimation. If a
marine mammal is seen well outside the safety radius, the vessel may be
maneuvered to avoid having the mammal come within the safety radius
(see Mitigation). When mammals are detected within or about to enter
the designated safety radii, the airguns will
[[Page 60091]]
be powered-down immediately. The observer(s) will continue to maintain
watch to determine when the animal is outside the safety radius. If the
airguns are powered-down, observers will continue to maintain watch to
determine when the animal is outside the safety radius. Airgun
operations will not resume until the animal is outside the safety
radius or until the specified intervals (15 or 30 min) have passed
without a resighting.
If ramp-up procedures must be performed at night, two observers
will be on duty 30 minutes prior to the start of airgun operations and
during the subsequent ramp-up procedures. Ramp-up procedures for the
20-gun array will not commence at night unless the seismic source has
been maintained.
Reporting
A report will be submitted to NMFS within 90 days after the end of
the cruise. The end of the Caribbean cruise is predicted to occur on
approximately 21 February 2004. The report will describe the operations
that were conducted and the marine mammals that were detected. The
report will be submitted to NMFS, providing full documentation of
methods, results, and interpretation pertaining to all monitoring
tasks. The 90-day report will summarize the dates and locations of
seismic operations, marine mammal sightings (dates, times, locations,
activities, associated seismic survey activities), and estimates of the
amount and nature of potential take of marine mammals by harassment or
in other ways.
Endangered Species Act (ESA)
Under section 7 of the ESA, NMFS has begun consultation on the
proposed issuance of an IHA under section 101(a)(5)(D) of the MMPA for
this activity. Consultation will be concluded prior to the issuance of
an IHA. LDEO has initiated consultation with the U.S. Fish and Wildlife
Service on West Indian Manatees.
National Environmental Policy Act (NEPA)
The NSF has prepared an EA for the Southeast Caribbean surveys.
NMFS is reviewing this EA and will either adopt it or prepare its own
NEPA document before making a determination on the issuance of an IHA.
A copy of the NSF EA for this activity is available upon request (see
ADDRESSES).
Preliminary Conclusions
NMFS has preliminarily determined that the impact of conducting the
seismic survey in the Southeast Caribbean Sea and Adjacent Atlantic
Ocean, off the coast of Venezuela, will result, at worst, in a
temporary modification in behavior by certain species of marine
mammals. This activity is expected to result in no more than a
negligible impact on the affected species or stocks.
While the number of potential incidental harassment takes will
depend on the distribution and abundance of marine mammals in the
vicinity of the survey activity, the number of potential harassment
takings is estimated to be small. In addition, no take by injury and/or
death is anticipated, and the potential for temporary or permanent
hearing impairment is low and will be avoided through the incorporation
of the mitigation measures mentioned in this document. In addition, the
proposed seismic program is not expected to interfere with any
subsistence hunts, since operations in the whaling and sealing areas
will be limited.
Proposed Authorization
NMFS proposes to issue an IHA to LDEO for conducting a seismic
surveys in the Southeast Caribbean Sea and Adjacent Atlantic Ocean, off
the coast of Venezuela, provided the previously mentioned mitigation,
monitoring, and reporting requirements are incorporated. NMFS has
preliminarily determined that the proposed activity would result in the
harassment of small numbers of marine mammals; would have no more than
a negligible impact on the affected marine mammal stocks; and would not
have an unmitigable adverse impact on the availability of species or
stocks for subsistence uses.
Information Solicited
NMFS requests interested persons to submit comments and information
concerning this request (see ADDRESSES).
Dated: October 14, 2003.
Donna Wieting,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 03-26549 Filed 10-20-03; 8:45 am]
BILLING CODE 3510-22-S