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NOAA Technical Memorandum NMFS-NWFSC-45
Heather A. Stout1, Richard G. Gustafson2,William H. Lenarz3, 1Northwest Fisheries Science Center Fishery Resource Analysis and Monitoring Division Hatfield Marine Science Center 2030 South Marine Science Drive Newport, OR 97365 2Northwest Fisheries Science Center 3College of Marin 5Northwest Fisheries Science Center
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service |
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.
Reference 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., R.G. Gustafson, W.H. Lenarz, B.B.
McCain, D.M. VanDoornik,
T.L. Builder, and R.D.
Methot. 2001. Status review of Pacific Herring in
Puget Sound, Washington. U.S.
Dept. Commer.,
NOAA
Tech. Memo. NMFS-NWFSC- 45, 175 p.
Most NOAA Technical Memorandums NMFS-NWFSC are
available on-line at the Northwest Fisheries Science Center
web site (http://www.nwfsc.noaa.gov)
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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 National Marine Fisheries Service (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, 1814); 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 formed three Biological Review Teams (BRTs): one for Pacific hake, Pacific cod, and walleye pollock; another for copper, quillback and brown rockfish; and the last for Pacific herring. These BRTs were composed of federal scientists with expertise in one or more of these species, to conduct these status reviews. This report summarizes the biological and environmental information gathered in that process and the scientific conclusions reached by the BRT for Pacific herring in Puget Sound.
The BRT examined environmental, geologic, biogeographic, life-history, and genetic information in the process of identifying DPSs. Biogeography, ecological and habitat factors, and genetic population structure were found to be the most informative for this species. The four DPS options considered in this evaluation were:
A. A separate DPS for each of the five basins of greater Puget Sound, which are: Hood Canal, Main Basin, Whidbey Basin, the Strait of Juan de Fuca/San Juan Islands, and South Sound.
B. A DPS for two regions within the Georgia Basin, which are: Puget Sound proper (that portion of Puget Sound south of Admiralty Inlet and east of Deception Pass), and in north Puget Sound including the Strait of Juan de Fuca/San Juan Islands north to the mouth of the Fraser River and west to Cape Flattery.
C. A DPS that encompasses Georgia Basin, extending from the southern end of Puget Sound proper to the northern end of the Strait of Georgia near Discovery Passage and westward to Cape Flattery.
D. A single DPS that includes the populations in the area from Baja California to Southeast Alaska, with the northern boundary being the border of the zoogeographic zone near Dixon Entrance, or a line between Helm Bay and Lynn Canal, Alaska.
A majority of the BRT favored the Georgia Basin, which is option C, as the most likely DPS, with options B and D receiving considerably less support. No member of the BRT supported DPS option A. Members of the BRT utilized a variety of evidence to support their identification of a Georgia Basin DPS for Pacific herring. These included tagging studies in the Canadian portion of the Georgia Basin, vertebral counts, information on larval distribution and transport, as well as hydrographic studies conducted by the Department of Fisheries and Oceans Canada (DFO). Genetic studies by Grant and Utter (1984) were also utilized in concert with work by McQuinn (1997) on Atlantic herring that describes the hypothesized metapopulation stock structure in herring. Based on this examination, the BRT identified a DPS for the Georgia Basin, which includes Puget Sound, and it focused the risk analysis on this 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 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 utilized Wainwright and Kope (1999), West (1997) and Musick et al. (2000) to assist in organizing the information presented regarding risk to the herring populations that comprise this DPS. The BRT concluded, by a large majority, that the Georgia Basin DPS of Pacific herring is neither at risk of extinction, nor likely to become so. The BRT also concluded that, at this time, the Georgia Basin DPS of Pacific herring does not meet the International Union for the Conservation of Nature (IUCN) criteria to be considered "vulnerable" (Musick et al. 2000). However, most members expressed concern that they could not entirely rule out the possibility that this Georgia Basin DPS at present is likely to become in danger of extinction, especially because some stocks within the Georgia Basin, such as Cherry Point and Discovery Bay, have declined to such an extent that they may meet the IUCN criteria to be considered "vulnerable" which is "(of special concern), not necessarily endangered or threatened severely, but at possible risk of falling into one of these categories in the near future" (Musick et al. 2000). Although, the BRT recognized that herring populations in north Puget Sound and Puget Sound proper may be vulnerable to extinction, these populations represent a relatively small portion of the overall DPS of herring in the Georgia Basin. Moreover, because of the moderate to high productivity of herring populations and the tendency of herring to stray among spawning sites, the BRT felt that there are reasonable possibilities at present for recolonization of depleted populations associated with specific spawning sites.
However, the BRT emphasized that while the DPS is defined at a larger scale than the stocks that are managed in Puget Sound by Washington Department of Fisheries and Wildlife (WDFW), and that the Georgia Basin DPS does not appear at risk of extinction at present, local populations are the appropriate scale for fisheries management activities, and, as McQuinn (1997) emphasizes, their "conservation is essential for the preservation of spawning potential and for the viability of coastal fisheries."
It is important to note that the BRT's considerations of the status and trends of Pacific herring in the Puget Sound area did not, and should not, occur in a vacuum. In addition to Pacific herring, several other fish species from this area have either been listed under the ESA, or have been petitioned for listing. These include at least 20 evolutionarily significant units (ESUs) of anadromous salmonids in the Pacific Northwest, copper, quillback and brown rockfish, Pacific cod, Pacific hake, and walleye pollock which are all in or close to the 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 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, we find 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 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 Puget Sound compared to surrounding and similar environments, many of which are interconnected with the Sound via factors including the climate, currents, migrations, and dispersal of various species. It is 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 is noted in this regard. So are 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 Puget Sound ecosystem, are important for the following reasons: as a basis for judging how problematic the picture before us is, to what degree the 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. This leaves some members with the concern that, while action under the strict guidelines established under ESA may not be warranted, there is evidence pointing to the potential for anthropogenic factors to be disrupting the Puget Sound Ecosystem. If we fail to close the gaps in our understanding necessary to determine what, if any, steps can be taken to address the adverse human effects on the ecosystem, permanent loss of marine and nearshore biodiversity may be the result in Puget Sound.
The status review for Puget Sound Pacific herring was conducted by a team of scientists from the National Marine Fisheries Service (NMFS), Northwest Fisheries Science Center (NWFSC), 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 Pacific herring extinction-risk assessments are the contribution of Dr. William H. Lenarz. The authors acknowledge the efforts of all who contributed to this record, especially the Washington Department of Fish and Wildlife (WDFW) and Department of Fisheries and Oceans Canada (DFO).
Numerous individual fishery scientists and managers provided information that aided in preparation of this document and deserve special thanks. We particularly wish to thank Kurt Stick and Mark O�Toole from WDFW for updated information, data, opinions, and advice. Others who provided significant contributions to this effort include Greg Bargmann, Jim West, Morris Barker and Jack Tagart from WDFW. The assistance and historical perspective of Dr. Thomas C. Wainwright of the Fish Ecology Division of 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 Mary Breaker and Jim Bottom of Fishery Resource Analysis Monitoring (FRAM) of NWFSC are much appreciated.
The BRT for Puget Sound Pacific herring consisted of the following members: Tonya L. Builder, Dr. Bruce B. McCain, Dr. Richard Gustafson, Dr. Richard D. Methot, Dr. Peter W. Lawson, Heather A. Stout, Donald M. Van Doornik, and Dr. Robin S. Waples from the Northwest Fisheries Science Center; Dr. Charles Fowler and Mark Carls from the Alaska Fisheries Science Center; Dr. Alan Mearns from the National Ocean Survey; and, Curtis D. Tanner from U.S. Fish and Wildlife Service.