Technical Memorandum NMFS-NWFSC-46
Heather A. Stout1, Bruce
B. McCain1, Russel D. Vetter2,
1National Marine Fisheries Service
2National Marine Fisheries Service
3National Marine Fisheries Service
4College of Marin
5National Marine Fisheries Service
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Marine Fisheries Service
NOAA-NWFSC Tech Memo-46: Status Review of Copper Rockfish (Sebastes caurinus), Quillback Rockfish (S. maliger), and Brown Rockfish (S. auriculatus) in Puget Sound, Washington
NOAA Technical Memorandum NMFS Series
The Northwest Fisheries Science Center of the National Marine Fisheries Service, NOAA, uses the NOAA Technical Memorandum NMFS series to issue informal scientific and technical publications when complete formal review and editorial processing are not appropriate or feasible due to time constraints. Documents published in this series may be referenced in the scientific and technical literature.
The NMFS-NWFSC Technical Memorandum series of the Northwest Fisheries Science Center continues the NMFS-F/NWC series established in 1970 by the Northwest & Alaska Fisheries Science Center, which has since been split into the Northwest Fisheries Science Center and the Alaska Fisheries Science Center. The NMFS-AFSC Technical Memorandum series is now being used by the Alaska Fisheries Science Center.
throughout this document to trade names does not imply endorsement by the
National Marine Fisheries Service, NOAA.
This document should be cited as follows:
Stout, H.A., B. B. McCain, R. D. Vetter, T. L.
Builder, W. H. Lenarz, L. L. Johnson, and R.D.
Methot. 2001. Status review of Copper Rockfish,
Quillback Rockfish, and Brown Rockfish in
Puget Sound, Washington. U.S. Dept. Commer.,
NOAA Tech. Memo. NMFS-NWFSC- 46, 158 p.
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The Endangered Species Act (ESA) allows the listing of "distinct population segments"(DPSs) of vertebrate species or subspecies as threatened or endangered, if severe declines in abundance are indicated or substantial risks are facing the species. Thus, two key questions must be addressed in determining whether a listing under the ESA is warranted: 1) Is the entity in question a "species" as defined by the ESA? and 2) If so, is the "species" in danger of extinction (endangered) or likely to become so (threatened)? Guidance on what constitutes a "distinct population segment" is provided by the joint U.S. Fish and Wildlife Service (USFWS) and NMFS interagency policy on vertebrate populations (USFWS-NMFS 1996). Once a DPS is identified, NMFS considers a variety of factors in determining whether a listing is warranted.
In response to a petition (Wright 1999) to list 18 species of marine fish in Puget Sound under the ESA, NMFS initiated status reviews of seven of these species: Pacific hake, Merluccius productus (Ayres, 1855); Pacific cod, Gadus macrocephalus (Tilesius, 1810); walleye pollock, Theragra chalcogramma (Pallas, 1815); Pacific herring, Clupea pallasi (Valenciennes, 1847); brown rockfish, Sebastes auriculatus (Girard, 1854); copper rockfish, S. caurinus (Richardson, 1845); and quillback rockfish, S. maliger (Jordan and Gilbert, 1880). The National Marine Fisheries Service (NMFS) formed a Biological Review Team (BRT), composed of scientists with expertise in one or more of these species, to conduct these status reviews. This status review summarizes the biological and environmental information gathered in that process and the preliminary conclusions reached by the BRT for brown rockfish, copper rockfish and quillback rockfish. This document is part of a larger effort by the National Marine Fisheries Service to complete status reviews for all seven of the petitioned species of marine fish in Puget Sound.
Due to substantial variation in usage of the term "Puget Sound", we have adopted conventions for geographical regions in the inland waters of Washington State and British Columbia. Puget Sound proper is defined as the marine waters south of Admiralty Inlet and east of Deception Pass. North Puget Sound is defined by the United States-Canadian border on the north, a line due north of Cape Flattery on the west, the mainland on the east and a line drawn between Point Wilson and Partridge Point on Whidbey Island on the south. Washington Department of Fish and Wildlife (WDFW) defines their North Puget Sound sampling area at a line drawn due north of the Sekiu River, however, the petitioner included the area between the Sekiu River and Cape Flattery in the petition for listing. In order to complete the status review process, the area between the Sekiu River and Cape Flattery is included as North Puget Sound in these deliberations. No genetic samples were taken in the area west of the Sekiu River to Cape Flattery, so this change should not affect the outcomes of the DPS delineations or risk analyses. Greater Puget Sound refers to the area of North Puget Sound and Puget Sound proper combined. The Strait of Georgia is the body of water separating the southern portion of Vancouver Island and the British Columbia mainland. It extends from the northern boundary of North Puget Sound to Cortes Island and Desolation Sound in the north. The Georgia Basin includes all of greater Puget Sound and the Strait of Georgia in British Columbia.
The BRT examined environmental, geologic, biogeographic, life-history, and genetic information in the process of identifying DPSs. In particular, biogeography, ecological and habitat factors, and genetic population structure were found to be most informative for the species considered in this status review. Based on this examination, the BRT identified a DPS for each of the three rockfish species in Puget Sound proper that can be considered a species under the ESA. The BRT also concluded that there is good reason to believe that copper and quillback rockfish found in North Puget Sound are part of a northern Puget Sound DPS with rather uncertain northern and western boundaries. Brown rockfish are uncommon in North Puget Sound and most likely represent vagrants from the Puget Sound proper DPS.
The ESA (Section 3) defines the term "endangered species" as "any species which is in danger of extinction throughout all or a significant portion of its range." The term "threatened species" is defined as "any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range." According to the ESA, the determination of whether a species is threatened or endangered should be made on the basis of the best scientific information available regarding its current status, after taking into consideration conservation measures that are proposed or are in place. In this status review, the BRT did not evaluate likely or possible effects of conservation measures, and therefore did not make recommendations as to whether identified DPSs should be listed as threatened or endangered species. Rather, the BRT drew scientific conclusions about the risk of extinction faced by identified DPSs under the assumption that present conditions will continue. The BRT concluded that none of the Puget Sound proper or northern Puget Sound DPSs for these three species are at risk of extinction, but the level of available information leaves substantial uncertainty in this determination.
The rockfish BRT considered five possible configurations that incorporate greater Puget Sound populations of copper rockfish. The first is a coastwide DPS that encompasses Puget Sound proper. The second scenario includes a coastal DPS that includes the Queen Charlotte Islands, a Puget Sound proper DPS, a Gulf Island DPS, a northern Puget Sound DPS (including the San Juan Islands) whose boundaries are uncertain and a Strait of Georgia DPS whose boundaries cannot be defined at present. The third scenario consists of a coastal DPS, and a Georgia Basin DPS. A fourth scenario consists of a coastal and Gulf Islands DPS, and a Puget Sound proper DPS. (The Gulf Islands are located off of the west coast of Canada in the Strait of Georgia between Vancouver Island and the British Columbia mainland. The Gulf Islands are a part of the same archipelago as the American San Juan Islands.). The fifth and last scenario includes a coastal DPS, a Puget Sound proper DPS, and a northern Puget Sound DPS which includes the Canadian Gulf Islands and extends to an uncertain degree northward into the Georgia Basin and westward toward the coastal DPS. All BRT members agreed that the fifth scenario (Fig. 1) is the most consistent with available information for copper rockfish, although substantial uncertainties remain, especially with regard to the extent of the northern Puget Sound DPS.
Members of the BRT utilized a variety of evidence to support their identification of a Puget Sound proper DPS for copper rockfish. The preponderance was genetic in nature and came from work by Seeb (1998), Wimberger (In prep.) and Buonacoursi et al. (In prep.). The presence of a private allele in Puget Sound proper as well as assignment testing based on microsatellite genotypes provided convincing evidence of discreteness in the population. In addition, the life-history traits of copper rockfish such as live-bearing of young, internal fertilization, short-pelagic larval stages, fidelity to habitat and physical isolation due to current and water residence times in Puget Sound proper and North Puget Sound, provide isolating mechanisms that are consistent with a relatively high degree of genetic structure in copper rockfish populations. These physical characteristics were utilized as evidence of the significance of the populations in that they provide unusual or unique habitat features not experienced by other copper rockfish populations.
The BRT also agreed that genetic evidence points to a possible separate northern Puget Sound DPS for copper rockfish. Uncertainties do exist with regard to this DPS delineation, however. The oceanography of North Puget Sound, Gulf Islands and rest of the Georgia Basin is sufficiently restricted from the outer coast to reasonably allow reproductive isolation, but it is not as restricted or as unique as Puget Sound proper. Also, there are no genetic data for the rest of the Georgia Basin, so the question remains as to how Gulf Islands fish relate to the rest of the Georgia Basin as well as to the coast. Support was given to additional studies aimed at clarifying this information in the near future.
The BRT utilized criteria and methods of Wainwright and Kope (1999) and Musick et al. (2000) to assist in organizing the information presented regarding risk to the Puget Sound proper DPS. Bearing the results of the above comparisons in mind, the BRT considered whether the Puget Sound proper copper rockfish DPS was in danger of extinction, likely to become in danger of extinction, or not likely to become in danger of extinction. The majority of the BRT concluded that the Puget Sound proper DPS of copper rockfish are neither at risk of extinction nor likely to become so. However, most members expressed concern they could not entirely rule out the possibility that this species at present is likely to become in danger of extinction. The BRT also concluded that this DPS met the International Union for the Conservation of Nature (IUCN) criteria to be considered vulnerable (Musick et al. 2000). The BRT agreed that populations of this species had declined over the last three or four decades, with over_harvesting being a likely major factor. Nevertheless, the populations in the DPS had appeared to be stable over the last five years, and the lower population numbers in this DPS compared to the larger numbers in northern Puget Sound are roughly in proportion to the greater amounts of kelp and high-relief habitat in North Puget Sound. The BRT considered the risk to copper rockfish in North Puget Sound to be no greater than the risk to copper rockfish in Puget Sound proper. The BRT also expressed caution that important changes in resource management practices (e.g., increased harvest levels) and in the ecosystem (e.g., increased numbers of marine mammals or predatory fish species), as well as increased habitat degradation, could result in increased extinction risk for copper rockfish in this DPS.
Members of the BRT considered three possible configurations that incorporate greater Puget Sound populations of quillback rockfish. The first scenario includes a coastwide DPS that encompasses greater Puget Sound. A small minority of the BRT supported this scenario. The second DPS configuration includes a coastal and San Juan Islands DPS and a Puget Sound proper DPS. A slightly larger, small minority favored this scenario. The third configuration is a coastal DPS, a Puget Sound proper DPS and a northern Puget Sound DPS which extends into the Georgia Basin and toward the coast to an uncertain degree. A majority (66%) of the BRT approved of this DPS scenario for quillback rockfish. The geographic boundaries of the Puget Sound proper DPS, northern Puget Sound DPS and the coastal DPS are shown in Figure 2.
A variety of evidence was utilized by the BRT to support their tentative identification of a Puget Sound proper DPS for quillback rockfish. Most was genetic in nature and came from the allele and microsatellite work by Seeb (1998), and Wimberger et al. (In prep). BRT members also considered that the life-history traits of quillback rockfish, such as live-bearing of young, internal fertilization, short-pelagic larval stages, fidelity to habitat and physical isolation due to current and water residence times in Puget Sound proper, provide appropriate isolating mechanisms that would allow a relatively high-degree of genetic structure in quillback rockfish populations. These life-history traits are evidence of the significance of the populations in that it is unusual or unique and differs markedly from other populations.
The boundaries of the northern Puget Sound DPS are not certain. It extends to an uncertain degree northward into the Canadian portion of the Georgia Basin and its western boundary is provisionally placed at Cape Flattery. The BRT concluded that the Puget Sound proper quillback rockfish are different from the coast, but beyond Puget Sound proper, there is no genetic evidence of structure in the population to support differences between the San Juan Islands and the coast. However, the similarities of quillback and copper rockfish life histories and the oceanographic features of North Puget Sound led the BRT to conclude that the isolating mechanisms for copper rockfish probably apply to quillback rockfish as well. This led to the identification of a northern Puget Sound DPS for quillback rockfish. More genetic information is needed to clarify the existence and extent of this northern Puget Sound DPS.
The BRT, bearing in mind their deliberations regarding risk, using West (1997), Wainwright and Kope (1999), and Musick et al. (2000), considered whether the Puget Sound proper DPS of quillback rockfish was in danger of extinction, likely to become in danger of extinction or not likely to become in danger of extinction. The majority of the BRT concluded that the Puget Sound proper DPS of quillback rockfish are neither at risk of extinction nor likely to become so. However, most members expressed concern that they could not rule out the possibility that this species at present is likely to become in danger of extinction. The BRT also concluded that this DPS met the IUCN criteria to be considered vulnerable. The BRT agreed that populations of quillback rockfish had, according to a self-contained underwater breathing apparatus (SCUBA) survey, declined to 14% of its 1988 size, with over_harvesting being a likely major factor. Nevertheless, the populations in the DPS had appeared to be stable over the last five years, and the lower population numbers in this DPS compared to the larger numbers in North Puget Sound are roughly in proportion to the greater amounts of kelp and high-relief habitat in North Puget Sound. The BRT considers the risk to quillback rockfish in North Puget Sound to be no greater than the risk to quillback rockfish in Puget Sound proper. The BRT also expressed the same caution as they did with copper rockfish, which is that important changes in resource management practices (e.g., increased harvest levels) and in the ecosystem (e.g., increased numbers of marine mammals or predatory fish species), as well as increased habitat degradation, could result in increased extinction risk for this species in Puget Sound proper and in North Puget Sound.
Two possible configurations were considered by the BRT that incorporate greater Puget Sound populations of brown rockfish. The first is a coastwide DPS that includes greater Puget Sound. None of the BRT considered that this describes the appropriate scale for the DPS. The second scenario includes a coastal DPS, and a Puget Sound proper DPS. All members of the BRT supported this second DPS delineation (Fig. 3). As with quillback and copper rockfish, the geographic boundaries of the Puget Sound proper DPS are the area south of Admiralty Inlet and east of Deception Pass. Unlike copper and quillback rockfish, brown rockfish are uncommon in North Puget Sound. The few brown rockfish found outside of Puget Sound proper and inland of Cape Flattery are considered to most likely represent vagrant brown rockfish from the Puget Sound proper DPS.
The BRT identified a variety of evidence to support a Puget Sound proper DPS for brown rockfish. Genetic evidence comes from work by Seeb (1998). Brown rockfish have somewhat different life history and habits than do quillback and copper rockfish. However, key life-history traits, that would contribute to isolation of copper and quillback rockfish, are true of brown rockfish as well. These traits include live-bearing of young, internal fertilization, and short-pelagic larval stages. Physical isolation due to current and water residence times in Puget Sound proper also provide an isolating mechanism that is consistent with a relatively high-degree of genetic structure in brown rockfish populations in Puget Sound proper. The distribution of brown rockfish is also important in that it occurs in Puget Sound proper with a large geographical disjunction between greater Puget Sound and Oregon. This makes it a possible remnant population in ecologically unique habitats when compared to the California population (those that have been sampled for genetic work). BRT members were confident that, based on genetic information, this Puget Sound proper DPS is different from the coastal DPS, although the extent of the coastal DPS is unknown.
The BRT used methods and criteria from Wainwright and Kope (1999) and Musick et al. (2000) to organize information regarding risk to the Puget Sound proper DPS of brown rockfish. They considered whether the species was in danger of extinction, likely to become in danger of extinction or not likely to become in danger of extinction. A majority of the BRT concluded that brown rockfish in Puget Sound proper are neither at risk of extinction nor likely to become so. Factors in this decision included the increasing numbers of brown rockfish observed in SCUBA surveys in central Puget Sound proper during the late-1990s, stable estimated population sizes observed in trawl surveys in the main stem of Puget Sound proper during the 1990s, and the increased relative percent of brown rockfish in the composition of recreationally-caught rockfish during the late-1990s. Moreover, brown rockfish are more habitat generalists than quillback and copper rockfish and consume a wider range of prey species, making them more adaptable to the types of intertidal and subtidal habitats and associated food organisms available in the DPS. However, most members also expressed concern that they could not entirely rule out the possibility that this species is at present likely to become in danger of extinction. The BRT also concluded that this DPS met the IUCN criteria to be considered vulnerable. The BRT considered brown rockfish in North Puget Sound and the Strait of Juan de Fuca to be associated with the Puget Sound proper DPS and to be vagrants from that DPS. The BRT expressed the same caution as they did with copper and quillback rockfish, that important changes in resource management practices (e.g., increased harvest levels) and in the ecosystem (e.g., increased numbers of marine mammals or predatory fish species), as well as increased habitat degradation, could result in increased risk of extinction for brown rockfish in greater Puget Sound.
It is important to note that the BRT's considerations of the status and trends of brown rockfish, copper rockfish and quillback rockfish in the greater Puget Sound did not, and should not, occur in a vacuum. In addition to these three species, several other fish species from this area have either been listed under the ESA, or have been petitioned for listing. These include over 20 ESUs of salmon and steelhead along the West Coast, Pacific herring, Pacific cod, Pacific hake, and walleye pollock -- all in or close to the greater Puget Sound area. A significance emerges from consideration of these species collectively that is not apparent when any one is considered alone. Joint consideration of these species together suggests ecosystem-level implications that are difficult or impossible to evaluate under terms of the ESA. It is possible, hypothetically, that the reduced or declining trends of each of the individual species in this group could be considered as insufficient for affording that species legal protection under the ESA. But taking no action, under such circumstances, might be a major mistake if this collective information is an indication that the greater Puget Sound area, as an ecosystem, is experiencing major change. Such changes could be of more far-ranging concern than could ever be recognized if any one species were considered individually.
Environmental variation, and general ecosystem dynamics, could easily lead
to at least some of the declines in abundance observed for any one of these
species. However, the BRT found the commonalities and synchronous nature
of the information to be compelling. Scientifically, this raises the need
to determine the degree to which these common changes are anthropogenic,
both for individual species and within the greater Puget Sound ecosystem
as a whole. The complexity of factors responsible for population fluctuations
emphasizes the need for better understanding of the unique features of
greater Puget Sound compared to surrounding and similar environments, many
of which are interconnected with the Sound via such things as the climate,
currents, migrations, and dispersal of various species. The BRT felt that
it was important to understand the natural variation within such systems
over various time scales from decades to thousands of years. The potential
for stratigraphic sediment analysis was noted in this regard, as were studies
of the dynamics of species compared across the observed diversity of life-history
strategies. Measures of the ebb and flow, or the extinction, recolonization,
and persistence of the populations of the various species in the greater
Puget Sound ecosystem were also considered important as a basis for judging
to what degree the adverse changes are of anthropogenic origins, and how
significant these changes are as a basis for taking management action.
In the absence of such information, the BRT was restricted to a largely
species by species consideration of the data.
The status review for greater Puget Sound brown rockfish, copper rockfish and quillback rockfish was conducted by a team of researchers from the National Marine Fisheries Service's (NMFS) Northwest Fisheries Science Center (NWFSC), Southwest Fisheries Science Center (SWFSC) and Alaska Fisheries Science Center (AKFSC). This biological review team (BRT; technical terms and abbreviations such as "BRT" are defined in the Glossary) relied on comments and informational reports submitted by the public and by state, tribal, and federal agencies. The authors acknowledge the efforts of all who contributed to this record, especially the Washington Department of Fish and Wildlife.
Numerous individual fishery scientists and managers provided information that aided in preparation of this status review and deserve special thanks. We particularly wish to thank Wayne Palsson from the Washington Department of Fish and Wildlife for updated information, data, opinions, and advice. Others who provided significant contributions to this effort include Greg Bargmann, Jim West, and Jack Tagart from WDFW. The assistance and historical perspective of Dr. Thomas C. Wainwright of the Fish Ecology Division at NWFSC was invaluable to this process. Thanks also are due to Peggy Busby of Conservation Biology Division of NWFSC for imparting her valuable knowledge of the logistics of the BRT process. Contributions from Jim Bottom and Mary Craig of Fisheries Resource and Monitoring Division of NWFSC are much appreciated.
BRT for greater Puget Sound brown, quillback and copper rockfish consisted
of the following members: from the Northwest Fisheries Science Center,
Tonya L. Builder, Lyndal L. Johnson, Dr. Bruce B. McCain, Dr. Richard D.
Methot, Heather A. Stout, and Dr. Robin Waples; from the Southwest Fisheries
Science Center, Dr. Stephen Ralston, Dr. Russell Vetter; and from the Alaska
Fisheries Science Center, Mark Wilkins, and Dr. Paul Spencer.