i ii Most NOAA Technical Memorandums NMFS-NWFSC are available on-line at the Northwest Fisheries Science Center web site (http://www.nwfsc.noaa.gov) Copies are also available from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 phone orders (1-800-553-6847) e-mail orders ([email protected]) iii iv v vi vii viii ix x xi xii xiii EXECUTIVE SUMMARY In 1994, the Northwest Region of the National Marine Fisheries Service (NMFS) received three petitions to list distinct populations of chum salmon (Oncorhynchus keta) from Puget Sound and the Strait of Juan de Fuca as threatened or endangered species under the Endangered Species Act (ESA). In response to these petitions and the more general concerns for the status of Pacific salmon throughout the region, NMFS announced that it would initiate ESA status reviews for all species of anadromous salmonids in the Pacific Northwest. These comprehensive reviews will consider all populations in the states of Washington, Idaho, Oregon, and California. This report summarizes the conclusions of the NMFS Biological Review Team (BRT) for the ESA status review of chum salmon. According to NMFS policy, populations of Pacific salmon will be considered “distinct” (and hence “species” as defined by the ESA) if they represent evolutionarily significant units (ESUs) of the biological species. Based on ecological, genetic, and life-history information developed during this status review from across the species range, the BRT identified four ESUs of chum salmon in the Pacific Northwest: 1) Puget Sound/Strait of Georgia ESU, which includes all chum salmon populations from Puget Sound, the Strait of Georgia, and the Strait of Juan de Fuca up to and including the Elwha River, with the exception of summer-run chum salmon from Hood Canal and the Strait of Juan de Fuca; 2) Hood Canal summer-run ESU, which includes summer-run populations from Hood Canal, Discovery Bay, and Sequim Bay on the Strait of Juan de Fuca; 3) Pacific coast ESU, which includes all natural populations from the Pacific coasts of California, Oregon, and Washington, west of the Elwha River on the Strait of Juan de Fuca; and 4) Columbia River ESU. The BRT also evaluated patterns of abundance and extinction risk for chum salmon for all ESUs. The team concluded that the Puget Sound/Strait of Georgia ESU is not presently at risk of extinction, nor is it likely to become so in the foreseeable future. Current abundance is at or near historic levels, with a total annual run size averaging over 1 million fish during the past 5 years. The majority of populations within this ESU have stable or increasing population trends, and all populations with statistically significant trends are increasing. The Puget Sound/Strait of Georgia ESU encompasses a great deal of diversity in chum salmon life-history patterns, including summer, fall, and winter runs. Only two populations of winter-run chum salmon were identified throughout the worldwide range of chum salmon, both of which are present in this ESU and spawn within a few miles of each other in southern Puget Sound. These winter-run populations are not large in size, and although they appear to be healthy with stable escapements, they represent a life-history pattern which is important to conserve. The BRT expressed concern that maintaining present population sizes of summer-run chum salmon in the Puget Sound/Strait of Georgia ESU may depend on supplementation programs. Concern was also expressed about effects on naturally spawning fish of high levels of supplementation and enhancement in the southern part of Puget Sound and Hood Canal and the high representation of non-native stocks in the ancestry of many hatchery stocks. xiv The BRT has concluded that the Hood Canal summer-run ESU is in danger of extinction. In 1994, petitioners identified 12 streams in Hood Canal that recently supported spawning populations of summer chum salmon. At the time of the petition, chum salmon runs in 5 of these streams may already have been extinct, and those in 6 of the remaining 7 showed strong downward trends. Similarly, summer chum salmon in Discovery and Sequim Bays were also at low levels of abundance. A variety of threats to the continued existence of these populations was identified, including degradation of spawning habitat, low river flows, possible competition among hatchery and naturally-produced juvenile chum salmon in Hood Canal, and high levels of incidental harvest in salmon fisheries in Hood Canal and the Strait of Juan de Fuca. New information from state and federal agencies demonstrated substantial increases in returning summer chum salmon to some streams in Hood Canal and the Strait of Juan de Fuca in 1995 and 1996. However, serious concerns for the health of this ESU remain. First, the population increases in 1995 and 1996 were limited to streams on the west side of Hood Canal, especially the Quilcene River system, while streams on the south and east sides of Hood Canal continued to have few or no returning spawners. Second, a hatchery program initiated in 1992 was at least partially responsible for adult returns to the Quilcene River system. Third, the strong returns to the west-side streams are the result of a single, strong year class, while declines in most of these streams have been severe and have spanned two decades. Last, greatly reduced incidental harvest rates in recent years probably contributed to the increased abundance of summer chum salmon in this ESU. In Hood Canal, these reductions have been implemented because of greatly reduced abundance of the target species, coho salmon (O. kisutch), rather than as a specific conservation measure for summer chum salmon. If coho salmon in the area rebound, and fishery management policies are not implemented to protect summer chum salmon, these populations could again face high levels of incidental harvest. The Pacific Coast ESU includes chum salmon from a large geographic area of considerable diversity. In the southern portion of the coastal ESU, neither the historic nor the present limit of spawning and distribution of chum salmon is known with certainty. Thus, it is unclear whether the historic range has been reduced. On the Oregon coast, almost all current production of chum salmon is natural, although abundance is low relative to historic levels. Habitat degradation appears to be the primary cause of the depressed status of these Oregon populations. On the outer Washington coast, little information is available on the abundance of natural populations, although annual adult escapements to Grays Harbor and Willapa Bay number in the tens of thousands. The percentage of hatchery fish in these escapements is unknown. Throughout the ESU there has been considerable hatchery enhancement and some transfer of fish or eggs both within and outside of the ESU. However, hatchery production has been relatively minor compared to natural production, and hatchery programs have used primarily local populations. Therefore, although the BRT had several concerns regarding the paucity of information, the majority conclusion is that the Pacific coast ESU is not presently at risk of extinction nor likely to become so. The Columbia River ESU historically supported commercial landings of hundreds of xv thousands of chum salmon, with annual landings of nearly half a million fish as recently as 1942. However, beginning in the mid-1950s, commercial catches declined drastically and now rarely exceed 2,000 per year (less than 50 fish per year have been caught since 1994). Historically, chum salmon also spawned in many Columbia River tributaries. Currently, the Washington Department of Fish and Wildlife (WDFW) recognizes and monitors only three natural populations in the Basin, one in Grays River and two in small streams near Bonneville Dam. All of these populations have been influenced by hatchery programs and fish transfers, including a hatchery on the Chinook River near the mouth of the Columbia River that had a return of 3,000 fish in 1993. Present-day populations in the Columbia River represent only a small portion of the historic chum salmon abundance and diversity. Substantial habitat loss in the Columbia River, its tributaries, and estuary was presumably an important factor in the decline and also represents a significant continuing risk for this ESU. Taking all of these factors into consideration, the BRT unanimously agreed that this ESU is at some risk. About half the members concluded that this ESU is at risk of extinction. The remaining members, citing population trends in recent years that indicate the monitored populations may be stable (albeit small), concluded that the ESU is not at substantial short-term risk of extinction but is likely to become so in the foreseeable future. xvi xvii ACKNOWLEDGMENTS This document represents the combined efforts of dozens of people who submitted information on chum salmon directly to the National Marine Fisheries Service, attended Biological and Technical Committee meetings, and answered seemingly endless questions from the authors and BRT members in person and by telephone. The authors particularly wish to acknowledge James Ames, Howard Fuss, Tim Tynan, and Stevan Phelps of the Washington Department of Fish and Wildlife, Nick Lampsakis and Dr. Robert Springborn of the Point No Point Treaty Council, and Carrie Cook, Tom Kane, and Dave Zajac of the U.S. Fish and Wildlife Service for generously sharing newly emerging data. We also wish to thank those who reviewed drafts of this and related documents. Significant contributions to the compilation and analysis of data were made by Ted Parker, Steve Lambert, and Tod McCoy, from the NMFS, Northwest Fisheries Science Center (NWFSC). The Biological Review Team for chum salmon consisted of the following members from the NWFSC: F. William Waknitz; Drs. Stewart Grant, Jeffrey Hard, Robert Iwamoto, Orlay Johnson, Robert Kope, Conrad Mahnken, Michael Schiewe, Robin Waples, and John G.