Endangered and Threatened Species: Puget Sound Populations of
Pacific Hake, Pacific Cod, and Walleye Pollock
[Federal Register: November 24, 2000 (Volume 65, Number 227)]
[Rules and Regulations]
[Page 70514-70521]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24no00-18]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Parts 223 and 224
[Docket No. 001103310-0310-01; I.D. 061199B]
Endangered and Threatened Species: Puget Sound Populations of
Pacific Hake, Pacific Cod, and Walleye Pollock
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of determination.
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SUMMARY: NMFS has completed an Endangered Species Act (ESA) status
review for Pacific cod (Gadus macrocephalus), Pacific hake (Merluccius
productus), and walleye pollock (Theragra chalcogramma) populations
from the eastern North Pacific Ocean between Puget Sound, Washington,
and southeast Alaska. After reviewing available scientific and
commercial information, NMFS has determined that none of the petitioned
populations in Puget Sound constitute ``species'' under the ESA. The
agency concludes that these populations are part of larger distinct
population segments (DPSs) that qualify as species under the ESA but do
not warrant listing as threatened or endangered at this time. However,
NMFS is adding the Georgia Basin Pacific hake DPS to the agency's list
of candidate species because of remaining uncertainties about its stock
structure and status.
DATES: Effective November 24, 2000.
ADDRESSES: Protected Resource Division, NMFS, 525 NE Oregon Street,
Suite 500, Portland, OR 97232. Reference materials regarding this
determination can be obtained via the Internet at www.nwr.noaa.gov/
1salmon/salmesa/pubs.htm.
FOR FURTHER INFORMATION CONTACT: Garth Griffin, NMFS, Northwest Region
(503) 231-2005, or Marta Nammack, NMFS, Office of Protected Resources
(301) 713-1401.
SUPPLEMENTARY INFORMATION:
Petition Background
On February 8, 1999, the Secretary of Commerce received a petition
from Sam Wright of Olympia, Washington to list and designate critical
habitat for 18 species of marine fishes in Puget Sound, Washington,
under the ESA. On June 21, 1999 (64 FR 33037), the agency accepted the
petition for seven of these species, including three members of the
family Gadidae (gadids): Pacific cod, Pacific hake, and walleye pollock
(also referred to as cod, hake, and pollock). The petitioner requested
listings for ``species/populations or evolutionary [sic] significant
units'' in Puget Sound, Washington. Under the ESA, a listing
determination can address a species, subspecies, or a distinct
population segment (DPS) of a species (16 U.S.C. 1532 (15)). The term
``evolutionarily significant unit'' is currently defined only for
Pacific salmonid DPSs (56 FR 58612, November 20, 1991). Therefore, for
definitions of these petitioned species, NMFS relied on the DPS
framework described in the joint NMFS/USFWS policy (61 FR 4722,
February 7, 1996), see ``Consideration as a `Species' Under the ESA''
section.
To ensure a comprehensive review, NMFS requested comments from any
party having relevant information concerning (1) biological or other
relevant data that may help identify gadid DPSs; (2) the range,
distribution, and size of these species' populations in Puget Sound and
coastal waters of Washington and British Columbia; (3) current or
planned activities and their possible impact on these species; and (4)
efforts being made to protect these species in Washington and British
Columbia. NMFS also requested
[[Page 70515]]
quantitative evaluations describing the quality and extent of estuarine
and marine habitats for these species, as well as information on areas
that may qualify as critical habitat in Washington. Although the status
review focused on the petitioned populations in Puget Sound, NMFS also
considered populations from the U.S. West Coast, British Columbia, and
southeast Alaska because of their geographic proximity and potential
relationship to gadid stocks in Puget Sound.
A NMFS Biological Review Team (BRT), comprising staff from NMFS'
Northwest Fisheries Science Center and Alaska Fisheries Science Center,
has completed a review of the best available scientific and commercial
information pertaining to cod, hake, and pollock from Puget Sound to
southeast Alaska (NMFS, 2000). This document summarizes the principal
results of this status review. Copies of the entire BRT report and
other documents pertaining to this review are available upon request
(see ADDRESSES).
Biological Background
The following section describes briefly the general physical
setting and biological attributes of cod, hake, and pollock. More
detailed information can be obtained from the NMFS status review (NMFS,
2000) and species accounts contained in Miller and Lea (1972), Hart
(1973), Eschmeyer et al. (1983), and Kessler (1985).
The petition focused on populations in Puget Sound, a fjord-like
estuary located in northwest Washington State that covers an area of
about 9,000 km2, including 3,700 km of coastline. It is subdivided into
five basins or regions: (1) North Puget Sound, (2) Main Basin, (3)
Whidbey Basin, (4) South Puget Sound, and (5) Hood Canal. The Georgia
Basin is an international water body that encompasses the marine waters
of Puget Sound, the Strait of Georgia, and the Strait of Juan de Fuca.
The coastal drainage of the Georgia Basin is bounded to the west and
south by the Olympic and Vancouver Island mountains, and to the north
and east by the Cascade and Coast Ranges. The petition addressed only
those stocks of hake and pollock in the Whidbey Basin, the Main Basin,
the Hood Canal, and the South Puget Sound. The petitioner stated that
fishery patterns, spawning locations, parasite markers, and tagging
studies indicate the existence of three population groups within Puget
Sound--one located in the Straits of Georgia and the area around
Bellingham, one in eastern Strait of Juan de Fuca and Port Townsend
Bay, and one in the area south of Admiralty Inlet that encompasses Hood
Canal, Agate Passage, and Dalco Passage.
Pacific Hake
Hake range from Sanak Island in the western Gulf of Alaska to
Magdalena Bay, Baja California, and are most abundant in the California
Current System (Hart, 1973; Bailey, 1982; NOAA, 1990; Love, 1991). In
addition to the abundant migratory population of Pacific hake that
spawn offshore from Cape Mendocino, California to southern Baja
California, several other stocks of Pacific hake have been identified,
including at least two that spawn in Puget Sound, several in the Strait
of Georgia, several in the west coast inlets of Vancouver Island, and a
small-bodied (``dwarf hake'') off the west coast of southern Baja
California (Nelson, 1969; Bailey et al., 1982; Ermakov, 1982; Bailey
and Yen, 1983; Beamish and McFarlane, 1985; Pedersen, 1985; Bollens et
al., 1992; Quirollo, 1992; Alados et al., 1993; Methot and Dorn, 1995;
Fox, 1997).
Hake may spawn more than once per season at depths between 130 and
500 m; spawning in Puget Sound occurs primarily from February through
April and peaks in March (W. Palsson, Washington Department of Fish and
Game (WDFW), pers. comm., 1999). Stocks in the Strait of Georgia and
Puget Sound spawn adjacent to major sources of freshwater inflow, near
the Frazer River in the Strait of Georgia and near the Skagit and
Snohomish Rivers in Port Susan (McFarlane and Beamish, 1985; Pedersen,
1985). Eggs hatch in 4 to 6 days, depending on the water temperature.
Larvae typically metamorphose into juveniles in 3 to 4 months
(Hollowed, 1992). Juveniles reside in shallow coastal waters, bays, and
estuaries (Dark, 1975; Bailey, 1981; Bailey et al., 1982; NOAA, 1990;
Dark and Wilkins, 1994; Dorn, 1995; Sakuma and Ralston, 1995; Smith,
1995) and move to deeper water as they get older (NOAA, 1990). Adult
hake school at depths between 50 and 500 meters (m) during the day,
then move to the surface and disband at night to feed (Sumida and
Moser, 1980; McFarlane and Beamish, 1986; Tanasich et al., 1991).
In Puget Sound and the Strait of Georgia, female hake mature at 4
to 5 years of age (McFarlane and Beamish, 1986) and growth ceases for
both sexes at 10 to 13 years (Bailey et al., 1982). The maximum age for
hake is about 20 years, but hake over age 12 are rare (Methot and Dorn,
1995). Absolute fecundity is difficult to determine because hake may
spawn more than once per season. Coastal stocks have 180-232 eggs/g
body weight, but Puget Sound and Strait of Georgia stocks have only 50-
165 eggs/g body weight (Mason, 1986). Bailey (1982) estimated that a
28-cm female had 39,000 eggs, while a 60-cm female had 496,000 eggs.
Pacific Cod
Cod are found in continental shelf and upper continental slope
waters of the North Pacific Ocean from Port Arthur, China, in the
northern Yellow Sea, around the North Pacific Rim, into the Bering Sea
as far north as the Chukchi Sea, and south along the North American
coast to Santa Monica Bay, California (Pinkas, 1967; Hart, 1973;
Bakkala et al., 1984; Allen and Smith, 1988; Love, 1991; Stepanenko,
1995; Westrheim, 1996). Cod are also found off the east coast of Japan
from Tokyo Bay to northern Hokkaido, on the west coast of Japan in the
Sea of Japan, and off the coasts of the Sakhalin and Kurile Islands
(Bakkala et al., 1984; Fredin, 1985). Off North America, the southern
limit of commercial cod fishing lies between Cape Flattery and
Destruction Island on the Washington outer coast (Ketchen, 1961).
Cod are an important groundfish in shallow, soft-bottomed marine
and estuarine habitats along the west coast (Garrison and Miller,
1982). Garrison and Miller (1982) reported that all cod life stages are
found in various bays in Puget Sound and in the Strait of Juan de Fuca.
Adults and large juveniles prefer mud, sand, and clay substrates,
although Palsson (1990) and Garrison and Miller (1982) found adults
associated with coarse sand and gravel substrates. Although cod are not
considered a migratory species, individual adult cod have been found to
move more than 1,000 km (NOAA, 1990; Shimada and Kimura, 1994).
Cod are single-batch spawners, releasing all ripe eggs in a single
spawning event within a few minutes' time (Sakurai, 1989; Sakurai and
Hattori, 1996). Spawning occurs from late fall to early spring in Puget
Sound (Garrison and Miller, 1982). Cod eggs are demersal, weakly
adhesive, and usually found associated with coarse sand and cobble
bottoms (Phillips and Mason 1986). Eggs and larvae are found over the
continental shelf between Washington and central California from winter
through summer (Dunn and Matarese, 1987; Palsson, 1990). Small
juveniles (between 60 and 150 mm in length) usually settle into
intertidal/subtidal habitats, commonly associated with sand and eel
grass, and gradually move into deeper water with increasing age (NOAA,
1990; Miller et al., 1976).
In British Columbia waters, 50 percent of the male cod have been
[[Page 70516]]
reported to be sexually mature at 41-53 cm, and 50 percent of the
females have been reported to be mature at 47-56 cm (Westrheim, 1996).
For cod spawning near Port Townsend, both sexes mature by 2 years and
45 cm (NOAA, 1990). In general, fecundity in cod has been estimated
between 225,000 and 5 million eggs per spawning female (Forrester,
1969; Alderdice and Forrester, 1971; Hart, 1973; NOAA, 1990; Palsson,
1990).
Walleye Pollock
Pollock are found in the waters of the northeastern Pacific Ocean
from the Sea of Japan, north to the Sea of Okhotsk, east to the Bering
Sea and Gulf of Alaska, and south along the Canadian and U.S. West
Coast to Carmel, California (Phillips, 1942 and 1943; Hart, 1973;
Bailey et al., 1999). Currents, eddies, and meso-scale physical coastal
structures influence the distribution of their early life-history
stages. The distributions of later life-history stages appear to be
influenced by temperature, light, and prey abundance--variables that
may change from year to year in a given area (Bailey, 1989; Swartzman
et al., 1994; Olla et al., 1996; Sogard and Olla, 1996a,b; Brodeur et
al., 1997). Adult pollock inhabit the continental shelf and slope
(Saunders et al., 1989), though various life-history stages are capable
of inhabiting nearshore areas, large estuaries (such as Puget Sound),
coastal embayments, and open ocean basins, such as the Aleutian Basin
of the Bering Sea (Bailey et al., 1999). Adults have been found as deep
as 366 m (Hart, 1973), but the vast majority range between 100 and 300
m. Larvae and small juveniles are generally found in the upper water
column to depths of 60 m (Garrison and Miller, 1982; Bailey et al.,
1999), but have been found in a variety of habitat types, including
eelgrass (over sand and mud), and over gravel and cobble substrates
(Miller et al., 1976). Pollock are not considered a migratory species,
but pre-spawning adults do make relatively short journeys to regional
spawning grounds (Muigwa, 1989).
During spawning, pollock apparently pair and spawn after a complex
courtship (Sakurai, 1982; Baird and Olla, 1991). Females spawn several
batches of eggs over a short period of time (Sakurai, 1982; Hinckley,
1987). Eggs are usually spawned in deep water and remain suspended in
the water column at 100-400 m at most spawning localities (Kendall et
al., 1994), but can also be spawned in shallower waters in coastal
bays. Larvae metamorphose into juveniles at a length of about 18 mm
(Bailey, 1989; Grover, 1990; Merati and Brodeur, 1996). In the first
year, juveniles grow about 1 mm per day, reaching 80-100 mm in length
in 6 months and 120-140 mm by the end of the first year. The growth
rates of juvenile and adult walleye pollock in the Georgia Basin appear
to be retarded compared with pollock from coastal waters.
In western Gulf of Alaska waters, males have been reported to be
sexually mature at age 3 and at a length of 29-32 cm; similarly, 3-
year-old females (30-35 cm) were sexually mature (Garrison and Miller,
1982). A study by Saunders et al. (1989) reports that male pollock from
coastal waters off of British Columbia reached a maximum length of
approximately 50 cm by age 7, whereas male pollock from the Strait of
Georgia reached a maximum length of 40 cm by age 5. Female pollock from
these areas showed a similar trend, but their maximum length was a few
cm longer. Fecundity estimates are not available for pollock in Puget
Sound (Matthews, 1987), and it is difficult to compare fecundity
between pollock from different regions because of the possibility of
interannual variability within regions (Hinckley, 1987) and the lack of
standardized methodology. However, some comparisons do reflect
geographical differences in fecundity between the Bering Sea, Shelikof
Strait, and Strait of Georgia (Miller et al.,1986).
Consideration as a ``Species'' Under the ESA
To qualify for listing as a threatened or endangered species, the
petitioned populations of Puget Sound cod, hake, and pollock must be
considered ``species'' under the ESA. Section 3(15) of the ESA defines
a ``species'' to include any ``distinct population segment of any
species of vertebrate which interbreeds when mature.'' On February 7,
1996, the U.S. Fish and Wildlife Service and NMFS adopted a policy to
clarify their interpretation of the phrase ``distinct population
segment of any species of vertebrate fish or wildlife'' for the
purposes of listing, delisting, and reclassifying species under the ESA
(51 FR 4722). The joint policy identifies two elements that must be
considered when making DPS determinations: (1) the discreteness of the
population segment in relation to the remainder of the species (or
subspecies) to which it belongs; and (2) the significance of the
population segment to the species or subspecies to which it belongs.
Discreteness. According to the joint policy mentioned above, a
population segment may be considered discrete if it satisfies either
one of the following conditions: (1) It is markedly separated from
other populations of the same taxon as a consequence of physical,
physiological, ecological, or behavioral factors; or (2) it is
delimited by international governmental boundaries across which there
is a significant difference in exploitation control, habitat
management, or conservation status.
Significance. The joint policy states that the following are some of
the considerations that may be used when determining the significance
of a population segment to the taxon to which it belongs: Persistence
of the discrete population in an unusual or unique ecological setting
for the taxon; evidence that the loss of the discrete population
segment would cause a significant gap in the taxon's range; evidence
that the discrete population segment represents the only surviving
natural occurrence of a taxon that may be more abundant elsewhere; or
evidence that the discrete population segment has marked genetic
differences from other populations of the species.
This is the first NMFS status review that attempts to apply the DPS
criteria to marine fish species over a broad geographic area of the
North Pacific Ocean and, as noted previously, the agency's assessment
included gadid stocks from a larger range (i.e., U.S. West Coast,
British Columbia and southeast Alaska) than that petitioned. NMFS
considered several kinds of information in this status review to
attempt to delineate DPSs of Pacific hake, Pacific cod, and walleye
pollock in Puget Sound. The first kind of information was habitat
characteristics that might indicate that the population segment
occupies an unusual or unique ecological setting for the species as a
whole. The second kind of information was to consider geographical
variability in phenotypic and life-history traits that may reflect
local adaptation. Such traits may have an underlying genetic basis, but
are often strongly influenced by environmental factors from one
locality to another. The third kind of information consisted of mark-
recapture studies, which give insight into the physical movement of
individuals between areas. The fourth kind of information consisted of
traits that are inherited in a predictable way and remain unchanged
throughout the life of an individual. Differences among populations in
the frequencies of these genetically determined traits may reflect
isolation between the populations. Based on the DPS criteria described
above and after assessing the best available scientific and commercial
information, NMFS has identified DPSs
[[Page 70517]]
for each of the three gadid species. The information reviewed and the
resultant DPS characterizations are summarized here.
Pacific Hake
There is considerable evidence indicating that Puget Sound and
Strait of Georgia stocks (inshore stocks) represent a population that
is distinct from coastal populations. Hake are most abundant in the
California Current system (Hart, 1973; Bailey, 1982; NOAA, 1990; Love,
1991). Coastal stocks spawn off California in the winter, then mature
adults begin moving northward and inshore, following the food supply
and Davidson currents (NOAA, 1990). Hake reach as far north as southern
British Columbia by fall, then by late fall they begin migrating to
southern spawning grounds and more offshore areas (Bailey et al., 1982;
Stauffer, 1985; Dorn, 1995; Smith, 1995). The inshore stocks follow
similar migration patterns but on a greatly reduced scale (McFarlane
and Beamish, 1986; Shaw et al., 1990). Hake that spawn in the Strait of
Georgia, in Puget Sound at Port Susan and Dabob Bay, and in Nootka
Sound, Barkley Sound, and Sydney Inlet on Vancouver Island are
essentially resident stocks, although they may undertake relatively
short spawning migrations (Ware and McFarlane, 1995). Puget Sound and
Strait of Georgia stocks spend their entire lives in these estuaries
(McFarlane and Beamish, 1986; Shaw et al., 1990), indicating that
little intermixing occurs between these populations and their coastal
counterparts.
In addition, available data show that inshore stocks have
substantially slower growth rates than the coastal hake (Alverson and
Larkins, 1969; Nelson and Larkins, 1970). Studies also indicate that
individuals in the inshore population are substantially smaller than
those in the coastal population, further suggesting discreteness
between the two populations (Nelson, 1969; Beamish, 1979; Pedersen,
1985). Puget Sound stocks appear to mature at a smaller size than
stocks in the Strait of Georgia (Nelson, 1969; Beamish, 1979; Pedersen,
1985), but this difference may have been caused by an intense
commercial hake fishery in Puget Sound (Pedersen, 1985).
NMFS also looked at otolith morphometrics to further evaluate
population discreteness. Otoliths from coastal hake were compared with
those from the Strait of Georgia hake and were found to be more
elongate and less concave in section (McFarlane and Beamish, 1985), and
an earlier study (Anonymous, 1968) reported that otoliths from Puget
Sound hake varied from those found in offshore hake. Although there
were no data to allow a comparison between Strait of Georgia and Puget
Sound stocks, the available evidence appears to lend further support to
the hypothesis that the coastal and inshore populations are distinct.
Parasitological data also suggest that inshore hake stocks do not
substantially intermingle with the coastal migratory stocks. A species
of protozoan parasite is present only in the coastal stock, indicating
that the parasite infected the offshore stocks after the inshore stocks
had been isolated in the Georgia Basin (Kabata and Whitaker, 1981 and
1985; McFarlane and Beamish, 1985). In contrast, there is not enough
information on parasite incidences to show whether Puget Sound stocks
are isolated from Strait of Georgia populations.
Genetic studies indicate that inshore hake stocks are
reproductively isolated from the offshore population. Samples collected
from fish in or near the spawning ground (Port Susan) and during
spawning show that allozyme frequencies differ significantly between
the inshore and the offshore populations (Utter, 1969; Utter and
Hodgins, 1969 and 1971; Utter et al., 1970). However, there are no
similar data to evaluate the degree of reproductive isolation between
Puget Sound and Strait of Georgia populations.
NMFS also reviewed available data to determine if hake in Puget
Sound and the Strait of Georgia occupied a unique setting within the
biological species as a whole. NMFS found that these are the only hake
populations to inhabit fjord-like environments. These hake spawn in
deep, inshore basins that receive large freshwater inputs, a much
different environment from the coastal hake that spawn 60 to 1,655 km
offshore (Saunders and McFarlane, 1997).
DPS Determination. NMFS concludes that the hake populations identified
by the petitioner do not constitute a ``species'' under the ESA, but
are part of a larger ``Georgia Basin Pacific hake DPS'' consisting of
inshore resident hake from Puget Sound and the Strait of Georgia. This
DPS encompasses at least five geographically discrete spawning
aggregates that are found in Dabob Bay and Port Susan in Puget Sound
and the south-central Strait of Georgia, Stuart Channel, and Montgomery
Bank in the Strait of Georgia.
Although NMFS could not with any certainty identify multiple
populations or DPSs of hake within the Georgia Basin, the agency
acknowledges the possibility that significant structuring may exist
within the proposed DPS and that such structure might be revealed by
new information. The agency expects to receive some new information in
the near future that will likely resolve many of the uncertainties
about the status and relationship of hake stocks within the Georgia
Basin DPS. When this information becomes available, and as resources
permit, NMFS will re-assess the configuration of this DPS.
Pacific Cod
Cod in Puget Sound have been categorized into three components by
the Washington Department of Fish and Wildlife: a North Sound component
located in U.S. waters north of Deception Pass (including the San Juan
Islands, Strait of Georgia, and Bellingham Bay), a West Sound component
(located west of Admiralty Inlet and Whidbey Island, and in the U.S.
section of the Strait of Juan de Fuca-- including Port Townsend), and a
South Sound component (located south of Admiralty Inlet).
To determine whether the petitioned Puget Sound populations are
distinct from each other (or from coastal stocks), NMFS analyzed
tagging studies to determine the amount of spawning fidelity within the
stocks. Although limited tagging data from Puget Sound and Strait of
Georgia spawning fish indicated some spawning fidelity, the same
studies also showed movement of spawning cod into other known spawning
areas, suggesting a larger stock structure. Tagging studies in the
eastern Bering Sea and adjacent waters found ``sufficient migration to
explain Grant et al.'s (1987) findings of genetic homogeneity in cod
over broad areas of the North'' (Shimada and Kimura, 1994). These
results support the hypothesis that Puget Sound populations are part of
a larger population group.
There are very few data on genetically based population structures
among Puget Sound cod. Genetic studies indicate that there is
reproductive isolation between western (Asia) and eastern (North
America including the Bering Sea) Pacific cod, but there is little
evidence to indicate isolation among North American stocks (Grant et
al., 1987). NMFS concluded that the current genetic information
suggests that Puget Sound cod are part of a larger distinct population;
however, NMFS does not rule out the possibility that genetic studies of
spawning fish may show a more substantial amount of genetic divergence
between populations.
[[Page 70518]]
NMFS analyzed other available information regarding the
reproductive isolation of Puget Sound cod but found no evidence to
support a Puget Sound DPS. For example, cod in their southern range are
relatively fast growing compared with other populations further north,
but this may simply be a function of increased metabolic activity and
longer growing seasons in warmer southern waters. Studies also suggest
that southern populations are isolated from northern populations
because they have higher size-specific fecundities than northern
stocks. However, this could be recruitment compensation for southern
populations that appear to grow and mature at faster rates and die at a
younger age than do cod from northern areas (Ketchen, 1961; Thomson,
1962; Foucher and Tyler, 1990). There was very little parasitological
information to show whether the cod population is structured on a finer
scale.
NMFS also analyzed habitat characteristics for cod at the
population level and determined that cod occupy and spawn in fjord-type
marine habitats along the coasts of British Columbia and southeastern
Alaska that are ecologically similar to those found in Puget Sound.
Thus, the Puget Sound ecological setting is not unique to cod, nor is
there geographical variability in the species phenotypic or life-
history traits that show local adaptation to fjord-like marine
habitats.
DPS Determination. NMFS concludes that the cod populations identified
by the petitioner do not constitute a ``species'' under the ESA, but
are part of a larger ``Pacific cod DPS'' consisting of cod populations
from Puget Sound to at least as far north as Dixon Entrance (near the
Queen Charlotte Islands, British Columbia). The agency considered
several possible DPS configurations for cod in the northeastern Pacific
Ocean in attempting to identify a ``discrete'' and ``significant''
segment of the biological species that incorporates Puget Sound cod
populations. While there are very few data at present to identify the
exact northern boundary of the DPS, the agency believes that the best
available information supports identifying a DPS that is substantially
larger than that identified by the petitioner.
Walleye Pollock
NMFS assessed information indicating persistent stock structure
throughout the species' range, suggesting that pollock exhibit homing
fidelity. However, though stock structure of pollock appears to be
persistent, little evidence for a direct parent/offspring linkage
exists. The broad area of spawning in the northeast Pacific Ocean and
the broad distribution of pelagic eggs and larvae also raise questions
about the level of isolation among local spawning populations. In
addition, this species is considered to be an opportunistic colonizer,
able to take advantage of ecological niches by rapid growth, early
maturity, and high fecundity (Bailey et al., 1999). This life history
characteristic suggests that pollock are able to inhabit areas where
they did not historically exist and to reoccupy areas that were once
inhabited.
Pollock show a more or less continuous distribution of spawning
sites from Puget Sound through southeast Alaska, and populations within
this range spawn from March to early June in the same locations year
after year. In contrast, Bering sea stocks spawn throughout a 10-month
period from January to October (Bulatov, 1989) and, possibly, into
November (Mulligan et al., 1989). Hence, the homogeneity of
reproductive traits among stocks from Puget Sound to southeast Alaska
suggests a larger population structure than that identified by the
petitioner. Unfortunately, there is not enough information from other
sources--e.g., tagging, parasite incidence, fecundity, and local
population genetics--to determine whether population structures should
be defined on a smaller scale. For example, there is little evidence to
show genetic differentiation of pollock populations at scales smaller
than Asia versus North America. However, a recent microsatellite DNA
study has shown statistically significant differences among pollock
samples collected in Puget Sound (Port Townsend), the southeastern
Bering Sea, and the Gulf of Alaska.
NMFS also analyzed habitat characteristics for pollock at the
population level and determined that pollock, like cod, inhabit and
spawn in marine habitats along the coasts of British Columbia and
southern Alaska that are ecologically similar to those found in Puget
Sound. These populations spawn in sea valleys, canyons, or indentations
in the outer margin of the continental shelf. They are also known to
spawn in fjords and deepwater bays whereas pollock in the Bering Sea
and Gulf of Alaska spawn over deep water and the continental shelf.
Thus, the Puget Sound ecological setting is not unique to pollock in
the eastern North Pacific Ocean.
Studies indicate that pollock densities and abundance decrease
markedly east of 140 deg. W longitude (Dorn et al., 1999a), and the
pollock management boundary between the Gulf of Alaska and southeast
Alaska has been set at this line of longitude. Also, zoogeographic
zones of coastal marine fishes and invertebrates further suggest a
pollock population structure that extends beyond Puget Sound but no
farther north than southeast Alaska. Two zones have been identified
within the lower boreal Eastern Pacific with a transition area found in
the coastal region from Puget Sound to Sitka, Alaska (Briggs, 1974;
Allen and Smith, 1988). In addition, many marine fish species common to
the Bering Sea extend southward into the Gulf of Alaska but apparently
no further south (Briggs, 1974). NMFS viewed this as further evidence
that Puget Sound pollock stocks are likely part of a larger population
that extends to southeast Alaska.
DPS Determination. NMFS concludes that the pollock populations
identified by the petitioner do not constitute a ``species'' under the
ESA, but are part of a larger ``Lower Boreal Eastern Pacific pollock
DPS'' consisting of pollock populations from Puget Sound to southeast
Alaska (i.e., at or near a boundary of 140 deg. W longitude). The
agency considered several possible DPS configurations for pollock in
the northeastern Pacific Ocean in attempting to identify a ``discrete''
and ``significant'' segment of the biological species that incorporates
Puget Sound populations. Some evidence suggests that multiple stocks
exist within this DPS, but the agency believes that the evidence is
insufficient to support a geographically smaller DPS.
Status of Hake, Cod, and Pollock DPSs
In considering whether these DPSs should be listed as threatened or
endangered under the ESA, NMFS evaluated both qualitative and
quantitative information. The qualitative evaluations included recent,
published assessments by a variety of sources, while quantitative
assessments were based on current and historical abundance information
and time series data compiled principally by fisheries agencies in
Washington and Canada.
Georgia Basin Pacific Hake DPS
The biomass of hake in Port Susan during the spawning period has
declined by 85 percent over the past 15 years, and total abundance has
dropped to less than 11 million fish in the year 2000. Size composition
and size at maturity for females have also decreased substantially. In
contrast, these changes are not evident among hake populations in the
Canadian portion of the Strait of Georgia. Saunders and McFarlane
(1999)
[[Page 70519]]
indicated that a conservative estimate of hake biomass in the Canadian
portion of the Strait of Georgia during the 1990s was about 50,000 to
60,000 metric tons (mt) and that biomass was stable during that decade.
Biomass estimates for the Port Susan population ranged from 10,648 mt
in 1990 to 2,365 mt in 1999. Using these estimates, the Port Susan hake
population constituted between 3.8 and 17.6 percent of the combined
Port Susan-Strait of Georgia population during the 1990s. Thus, if the
Canadian portion of the Strait of Georgia population is maintained,
loss of the Port Susan population does not appear to pose a serious
extinction risk for the entire Georgia Basin DPS.
There is a great deal of uncertainty regarding the effects of
potential risk factors on hake stocks within the Georgia Basin DPS.
While there are data on some risk factors, others are not well
documented or are only suspected to be factors for decline. Examples of
the latter include habitat alterations in Puget Sound, resulting in the
potential loss of eelgrass and kelp beds that contribute important hake
food sources, and changes in river flow patterns and increased
turbidity that could degrade habitat conditions. In contrast, NMFS was
able to examine more quantitatively the possible effects of harvest and
pinniped predation on hake in the Georgia Basin. Harvest rates by
commercial fishers showed a precipitous decline from 8,986 mt in 1982
to 41 mt in 1990, and by 1991 the fishery was closed because of low
abundances (W. Palsson, WDFW, pers. comm., 1999). NMFS (1997) estimated
that California sea lions consumed 830 mt of Puget Sound hake per year
(on average) between 1986 and 1994. This study also estimated that
harbor seals consumed 3,209 mt in eastern bays and 1,649 mt in Puget
Sound proper in 1993, and Saunders and McFarlane (1999) estimated that
harbor seals consumed 11,000 mt of hake in the Strait of Georgia in
1996.
Changes in migratory behavior among the offshore hake populations
appear to be related to environmental factors (Dorn, 1975). During warm
years, the offshore hake population is found off Canada during the
summer feeding season and, during the very warm period of the late
1990s, some hake apparently spawned off Washington and Canada (i.e.,
much further north than the typical spawning area off California and
Mexico) (Dorn et al., 1999a). The Port Susan population has apparently
changed more than the Canadian portion of the DPS. It is possible that
warm environmental conditions have caused the Port Susan area to be
relatively less favorable for hake spawning than the Canadian portion
of the Strait of Georgia. Some of the Port Susan population may have
migrated to Canadian waters, or perhaps there has been less movement
down from Canadian waters now than in previous years.
While some uncertainty remains regarding the geographic extent of
this DPS and its overall level of risk, available evidence suggests
that millions of hake are present in large parts of the DPS. Therefore,
NMFS concludes that the Georgia Basin Pacific hake DPS is not presently
in danger of extinction nor is it likely to become so in the
foreseeable future. Resources permitting, NMFS will re-assess the
status of this DPS when new information becomes available to resolve
remaining uncertainties about its stock structure and status.
Pacific Cod DPS
Commercial landings of cod off the U.S. west coast peaked in 1988
at 3,343 mt and have steadily declined since that peak to an estimated
404 mt in 1998. The majority of these landings are reported from
Washington State ports (Pacific Fishery Management Council, 1999). The
cod stock off the U.S. west coast reportedly is more prone to
recruitment failure than the northern stocks, suggesting that the
environmental conditions necessary for successful spawning and larval
success occur infrequently in this area (Dorn, 1993).
Status assessments for Puget Sound cod populations are based
primarily on trends in fishery statistics since 1970 (Palsson, 1990;
Palsson et al., 1997). Catches since 1970 have shown alternating
periods of good catch years with periods of poor catch years,
fluctuating around a 900-mt level between the mid-1970s and mid-1980s.
Catches peaked at 1,588 mt in 1980, then declined fairly steadily to
low levels--about 13.6 mt in 1994 (Palsson et al., 1997). Due to
concerns over the species' decline, commercial fishing for cod was
prohibited in Puget Sound south of Admiralty Inlet in 1987. Catch rates
north of Admiralty Inlet followed similar declines.
The primary stock indicator for Puget Sound, north of Admiralty
Inlet, was the catch rate from the commercial bottom trawl fishery
(Palsson et al., 1997). These catch rates generally declined between
the 1970s and 1994. However, data since 1994 (W. Palsson, WDFW, pers.
comm., 1999) indicate that catch rates in the bottom trawl fishery were
somewhat higher than the low in 1994. The primary stock indicator for
Puget Sound south of Admiralty Inlet was the catch rate from the
recreational fishery, which has also declined fairly steadily since the
late 1970s (Palsson, 1997). Recreational catches estimated from the
National Marine Recreational Fisheries Statistical Survey in Puget
Sound were 2,430 and 920 cod in 1996 and 1997, respectively (WDFW,
1998). Fishery statistics suggest that South Sound cod populations
(including Townsend Bay and Agate Passage) have also declined (Palsson
et al., 1997), prompting several harvest restrictions after 1989 to
protect these stocks.
Bottom trawl surveys have been conducted in Puget Sound
intermittently since 1987 (W. Palsson, WDFW, pers. comm., 1999).
Estimates for biomass and numbers of fish in 1987 were much higher than
in other years, but there has been no apparent trend in the estimated
abundance of cod in Puget Sound, both in number and weight, since the
1987 survey. In 1987, 1989, and 1991 when all Puget Sound management
regions were surveyed, the estimated cod biomass exceeded 2,500 mt, and
estimated cod numbers exceeded 4.7 million fish each year.
In British Columbia waters, four cod stocks are defined for
management purposes: Strait of Georgia, west coast Vancouver Island,
Queen Charlotte Sound, and Hecate Strait. The latter stock is the only
one to be recently evaluated and it appears to be at low levels. Annual
trawl fishery yields in Hecate Strait have varied between a high of
8,870 mt in 1987 to a low of 403 mt in 1996 (Canada Department of
Fisheries and Oceans (DFO), 1999). The most recent assessment indicates
that stock biomass was at historically low levels in 1994-96 (Haist and
Fournier, 1998) and that there has been a slight increase in the past 2
years. Recruitment estimates are low, and year-class strength continues
to be below-average. Projections for cod in Hecate Strait indicate that
the stock will decline in the next 2 years (DFO, 1999). Catch data for
the Strait of Georgia during 1970-1991 closely match those available
for Puget Sound (Schmitt et al., 1994). In both areas, catches
synchronously ranged between 500 and 1,000 mt during the early 1970s,
then rose to about 1,500 mt per year during the late 1970s and early
1980s. After a peak in 1981, catches fell to less than 100 mt by 1991.
Catches in the Strait of Georgia continued to decline, reaching zero by
1999.
Information on the status of cod in southeast Alaska is limited and
Gulf of Alaska assessments do not provide subarea estimates. However,
trawl biomass estimates from 1984-1999
[[Page 70520]]
indicate that cod abundance in southeast Alaska fluctuated between
4,000 mt in 1984 and 11,000 mt in 1990; 1999 estimates indicate that
cod stocks are near the highest level, about 10,000 mt (M. Martin,
NMFS, pers. comm., 2000).
There are insufficient data to conduct quantitative analyses of cod
extinction risks. However, Palsson (1990) discussed potential factors
contributing to the decline of cod in Puget Sound through the 1980s. He
concluded that the decrease in stock abundance corresponded to a change
to a warmer oceanographic regime, and to an increase in the abundance
of pinnipeds and in the fishing effort. Cod populations in Puget Sound
have remained low, though fishing effort for cod dropped substantially
during the 1980s and was extremely low during the 1990s. In addition to
those factors, West (1997) also considered the degradation of nearshore
nursery habitats to be a factor that may decrease juvenile cod
survival. Small juveniles usually settle into intertidal/subtidal
habitats that are commonly associated with sand and eel grass, and such
habitats have declined in both extent and quality in Puget Sound.
Studies indicate that cod are not major components of pinniped
diets (Schmitt et al., 1995), but pinniped predation risks have not
been evaluated quantitatively. Similarly, it is unclear how changes in
the abundance of other fish species may affect cod populations in Puget
Sound. For example, predation by salmonids is suspected since increased
releases of yearling chinook salmon from hatcheries in Puget Sound
appear to coincide with changes in cod abundance. Also, West (1997)
suggested that declines in the abundance of two primary prey species--
herring and pollock--may have contributed to cod declines in Puget
Sound. The effects that contaminants or toxins from phytoplankton
blooms (``red tides'') may have on cod abundance have also not been
evaluated.
As noted previously, NMFS could not identify a definitive northern
boundary for the Pacific cod DPS, but believes that it extends to at
least Dixon Entrance. Hence, the agency's risk assessment included a
greater number of cod stocks than those addressed in the petition.
While declines are evident throughout the DPS' range, it is unclear
whether they are attributable to natural phenomena that may be common
over the species' history. Cod in this DPS are at the southern extreme
of the species' range, and their current low abundance may represent a
temporary range shrinkage in response to unfavorable environmental
conditions. Still, it is apparent that cod persist throughout the range
of this DPS and that their abundance, particularly in the northern
portions of the DPS--does not suggest a detectable risk of
endangerment. Therefore, NMFS concludes that the Pacific cod DPS is not
presently in danger of extinction nor is it likely to become so in the
foreseeable future.
Lower Boreal Eastern Pacific Walleye Pollock DPS
Walleye pollock in southern Puget Sound are on the extreme southern
end of the species distribution, yet a sport fishery near Tacoma once
made them the most common bottomfish harvested in Puget Sound
recreational fisheries. Catches in southern Puget Sound exceeded 181 mt
per year from 1977 to 1986, but catches subsequently dropped, causing
the fishery to collapse (Palsson et al., 1997). Due to concerns about
the status of the population, the daily bag limit for pollock in the
recreational fishery in Puget Sound was reduced from 15 fish to 5 fish
in 1992, and from 5 fish per day to zero in 1997. Results of the Marine
Recreational Fisheries Statistical Survey indicate no pollock were
reportedly caught in recreational fisheries in Puget Sound during 1996
and 1997 (WDFW, 1998). North of Admiralty Inlet, trawl catch rates
between 1970 and 1994 were generally low, and catches were usually less
than 50 mt, except during the peak 1978-1981 period when catches
usually exceeded 500 mt. Palsson et al. (1997) reported that it is
unclear whether the stock is depressed, not targeted by the fishery, or
was simply unavailable to the fishery during these years.
Bottom trawl surveys have been conducted in Puget Sound
intermittently since 1987 (W. Palsson, WDFW, pers. comm., 1999).
Estimates for biomass and numbers of fish in 1987 were much higher than
in other years and the average sizes of pollock taken were usually
smaller. This may not represent a change in fish abundance, but may be
due to other factors. Otherwise, there was no apparent trend, except
that pollock abundance in central Puget Sound in 1995 was much larger
than in other years. In 1987, 1989, and 1991 when all Puget Sound
management regions were surveyed, the estimated pollock biomass
exceeded 975 mt, and abundance estimates exceeded 7 million fish each
year.
In British Columbia waters, discrete pollock stocks are present in
Dixon Entrance/Hecate Strait, Queen Charlotte Sound, west coast
Vancouver Island, and the Strait of Georgia. Pollock in Dixon Entrance/
Hecate Strait are thought to be part of a stock that includes the
southern waters of southeast Alaska, but the relationship with large
Gulf of Alaska stocks is unclear. It is possible that high abundance in
the Gulf of Alaska results in movement into northern Canadian waters
(Saunders and Andrews, 1998). During 1970-1991, when catch data were
available for Puget Sound and the Strait of Georgia, catch patterns in
the latter area closely matched those in Puget Sound until the late
1980s, when catch patterns began diverging (Schmitt et al., 1994).
A formal stock assessment for the southeast Alaska portion of the
Gulf of Alaska has not been conducted, and historically there has been
very little directed fishing for pollock in southeast Alaska. However,
commercial trawling is currently banned east of 140 deg. W, and bottom
trawl surveys indicated a substantial reduction in pollock abundance in
this region (Dorn et al., 1999b). Dorn et al. (1999b) noted that bottom
trawl survey data from southeast Alaska are highly variable, partially
as a result of differences in survey coverage among years. The 1996 and
1999 surveys had the most complete coverage of shallow strata in
southeast Alaska and indicated that the stock size of pollock was about
30,000 - 50,000 mt (Dorn et al. 1999b).
As noted previously, NMFS believes that this pollock DPS consists
of populations from Puget Sound to southeast Alaska, at or near a
boundary of 140 deg. W longitude. As with the Pacific cod DPS, pollock
populations in this DPS occupy the southern extreme of the species'
range and the agency's risk assessment included a greater number of
stocks than those addressed in the petition. Data were insufficient to
quantitatively assess the extinction risks for pollock, and the same
list of potential factors affecting cod abundance were considered as
potential risk factors for pollock. Unlike cod, British Columbia
pollock populations do not appear to be declining or at low levels,
although information on the status of these stocks is very limited.
Consequently, pollock stock declines apparent in Puget Sound do not
appear to be widespread throughout the DPS. Therefore, NMFS concludes
that the Lower Boreal Eastern Pacific Walleye Pollock DPS is not
presently in danger of extinction nor is it likely to become so in the
foreseeable future.
Determination
The ESA defines an endangered species as any species in danger of
extinction throughout all or a significant portion of its range, and a
threatened
[[Page 70521]]
species as any species likely to become an endangered species within
the foreseeable future throughout all or a significant portion of its
range. Section 4(b)(1) of the ESA requires that the listing
determination be based solely on the best scientific and commercial
data available, after conducting a review of the status of the species
and after taking into account those efforts, if any, that are being
made to protect such species.
After reviewing the best available scientific and commercial
information for these three gadids, NMFS concludes that none of the
petitioned populations in Puget Sound by themselves constitute
``species'' under the ESA. The agency determines that these populations
represent the southernmost stocks of larger DPSs that qualify as
species under the ESA: (1) a Georgia Basin Pacific hake DPS; (2) a
Pacific cod DPS that includes stocks at least as far north as Dixon
Entrance; and (3) a Lower Boreal Eastern Pacific walleye pollock DPS.
After assessing the risk of extinction faced by each DPS, NMFS further
determines that none of the DPSs warrant listing as threatened or
endangered at this time. NMFS acknowledges that the DPS and risk
assessments relied heavily upon the professional judgement of agency
scientists since robust data sets were generally not available for any
of the species. In particular, the agency believes that remaining
uncertainties regarding the status and relationship of hake stocks in
the Georgia Basin DPS warrant placing this DPS on the agency's list of
candidate species. In the event that new information becomes available
to resolve these uncertainties and as agency resources permit, NMFS
will conduct a thorough re-evaluation of this DPS.
References
A list of references is available upon request (see ADDRESSES).
Authority: 16 U.S.C. 1531-1543 and 16 U.S.C. 1361 et seq.
Dated: November 17, 2000.
William T. Hogarth
Deputy Assistant Administrator for Fisheries, National Marine Fisheries
Service.
[FR Doc. 00-30028 Filed 11-22-00; 8:45 am]
BILLING CODE 3510-22-S
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