i ii iii iv v vi vii EXECUTIVE SUMMARY The Endangered Species Act (ESA) allows listing of “distinct population segments” of vertebrates as well as named species and subspecies. The policy of the National Marine Fisheries Service (NMFS) on this issue for Pacific salmon and other anadromous salmonids is that a population will be considered “distinct” for purposes of the ESA if it represents an Evolutionarily Significant Unit (ESU) of the species as a whole. To be considered an ESU, a population or group of populations must 1) be substantially reproductively isolated from other populations, and 2) contribute substantially to ecological/genetic diversity of the biological species. Once an ESU is identified, a variety of factors related to population abundance are considered in determining whether a listing is warranted. In September 1994, in response to a petition seeking protection for Baker Lake (Washington) sockeye salmon under the ESA, NMFS initiated a coastwide status review of sockeye salmon (Oncorhynchus nerka) (Walbaum, 1792) in Washington, Oregon, and California, and formed a Biological Review Team (BRT) to conduct the review. This report summarizes biological and environmental information gathered in that process. West Coast Sockeye Salmon ESUs The BRT examined genetic, life history, biogeographic, geologic, and environmental information in the process of identifying ESUs. In particular, genetic data; physical, chemical, and biological characteristics of nursery lakes; sockeye salmon river entry and spawn timing; and smolt outmigration timing were found to be most informative for this process. Based on this examination, the BRT identified six sockeye salmon ESUs and one provisional ESU in Washington, as follows: 1) Okanogan River This ESU is named after the Okanogan River in the Columbia River drainage of Washington and includes all sockeye salmon that spawn in areas upstream from Lake Osoyoos, in Lake Osoyoos, or the downstream tributary Similkameen River (below Enloe Dam). The spawning and main rearing area for this ESU is in British Columbia, while the migration corridor for both juveniles and adults is through the Columbia River in Washington and Oregon. Important factors that differentiate this population as a separate ESU include: 1) the use of a very eutrophic lake-rearing environment (Lake Osoyoos), which is unusual for sockeye salmon, 2) the tendency for a relatively large percentage of the Okanogan River sockeye salmon population to return as 3-year-olds (age 1.1), 3) the juvenile outmigration- timing differences between Okanogan River and Lake Wenatchee-origin fish, 4) the adaptation of Okanogan River sockeye salmon to much higher temperatures during adult migration in the Okanogan River, and 5) protein electrophoretic data that indicate that this population is genetically distinct from other sockeye salmon currently in the Columbia River viii drainage. If “kokanee-sized” O. nerka observed spawning with sockeye salmon in the Okanogan River are identified as residual or resident sockeye salmon, then they are to be considered as part of the Okanogan River sockeye salmon ESU. 2) Lake Wenatchee This ESU is named after Lake Wenatchee on the Wenatchee River in the Columbia River drainage of Washington and includes all sockeye salmon that spawn above or in Lake Wenatchee and rear in Lake Wenatchee. Important factors that distinguish this ESU include electrophoretic data that indicate this population is genetically the second most distinctive population (after Redfish Lake, ID) within the contiguous United States, and life history and environmental differences with sockeye salmon from the Okanogan River ESU (juvenile outmigration timing, environmental differences in lake-rearing habitat, and age composition). If “kokanee-sized” O. nerka observed spawning with sockeye salmon in Lake Wenatchee tributaries are identified as residual or resident sockeye salmon, then they are to be considered as part of the Lake Wenatchee sockeye salmon ESU. 3) Quinault Lake This ESU is named after Quinault Lake on the Olympic Peninsula of Washington and includes all sockeye salmon that spawn in the Quinault River drainage and rear in Quinault Lake. Early river-entry timing, protracted adult run timing, extended lake residence prior to spawning, unusually lengthy spawn timing, unusual skin pigmentation of spawners, and genetic differences from other coastal Washington sockeye salmon are important factors in identifying this ESU. 4) Ozette Lake This ESU is named after Ozette Lake on the Olympic Peninsula of Washington and includes all sockeye salmon that spawn in the Ozette River drainage and rear in Ozette Lake. Important factors that distinguish this ESU include electrophoretic data that indicate this population is genetically distinct from all other sockeye salmon stocks in the Northwest, early river-entry timing, and the relatively large adult body size and large average smolt size of sockeye salmon in Ozette Lake compared to other coastal Washington sockeye salmon populations. If “kokanee-sized” O. nerka observed spawning with sockeye salmon in Ozette Lake are identified as residual or resident sockeye salmon, then they are to be considered as part of the Ozette Lake sockeye salmon ESU. 5) Baker River This ESU is named after the Baker River in the Skagit River drainage in northern Puget Sound, Washington and includes sockeye salmon that return to the Baker River. Important factors that distinguish this ESU include electrophoretic data that indicate that Baker River sockeye salmon are genetically distinct from sockeye salmon populations from ix the lower Fraser River and from other localities in Washington, the limnology of old Baker Lake (typically cold, oligotrophic, well-oxygenated, and influenced by glacial runoff, in contrast to other sockeye salmon systems under review with the exception of Lake Wenatchee), and the very large average smolt size of sockeye salmon in Baker Lake compared to other Washington sockeye salmon populations. 6) Lake Pleasant This ESU is named after Lake Pleasant on the Olympic Peninsula of Washington and includes sockeye salmon that ascend the Quillayute and Sol Duc Rivers and Lake Creek to spawn in Lake Pleasant. Important factors that differentiate this population as a separate ESU include: 1) protein electrophoretic data that indicate that this population is genetically distinct from other Washington sockeye salmon populations, 2) the distinctive small body size of adult spawners, and 3) the unusual age structure of the population, with significant numbers of juveniles remaining for 2 years in freshwater and/or spending only 1 year at sea. If “kokanee- sized” O. nerka observed spawning with sockeye salmon in Lake Pleasant are identified as residual or resident sockeye salmon, then they are to be considered as part of the Lake Pleasant sockeye salmon ESU. Big Bear Creek The Big Bear Creek provisional ESU is named after a tributary of the Sammamish River in the Lake Washington/Lake Sammamish Basin and includes sockeye salmon that spawn in Big Bear Creek and its two tributaries, Cottage Lake Creek and Evans Creek. Genetically, sockeye salmon from Big Bear and Cottage Lake Creeks are distinct from other stocks of sockeye salmon in the Lake Washington/Lake Sammamish drainage. A great deal of uncertainty remains concerning the historical presence of sockeye salmon within the Lake Washington/Lake Sammamish drainage prior to sockeye salmon transplants, which occurred in the 1930s-1950s. The relationship of this stock to native and transplanted kokanee is also uncertain, although genetically it is unlike the current parent stock from which these kokanee transplants originated (Lake Whatcom). If “kokanee-sized” O. nerka observed spawning with sockeye salmon in Big Bear Creek are identified as residual or resident sockeye salmon they are to be considered as part of the provisional Big Bear Creek sockeye salmon ESU. Other Population Units Historical records, stocking history, and genetic data indicate that sockeye salmon that spawn in the Cedar River, Issaquah Creek, and on lakeshore beaches in Lake Washington in the Lake Washington Basin and in the Methow and Entiat Rivers in the Columbia River Basin originated from transplants from outside these basins. Therefore, the BRT concluded that these populations are not presently considered as ESUs or as part of any other ESUs and are therefore not an ESA issue. The ESU status of two other population units could not be determined due to a lack of biological and historical information. These units are classified as follows: x 1) Riverine-spawning sockeye salmon This population unit consists of multiple aggregations of small numbers of sockeye salmon that spawn in Washington rivers without lake-rearing habitat. Although genetic data were available for riverine spawners in the Nooksack, Skagit, and Sauk Rivers, the data were insufficient to eliminate the possibility that these sockeye salmon may be derived from recent or historical straying of British Columbia lake-type or sea/river-type sockeye salmon. Genetic data were unavailable for riverine spawners in other Washington rivers on the west side of the Cascade Mountains. The BRT concluded that insufficient information exists concerning riverine-spawning sockeye salmon to make a decision as to this group’s ESU status. 2) Deschutes River, Oregon This population unit consists of sockeye salmon that are observed at the base of Pelton Re-regulating Dam on Oregon’s Deschutes River, a tributary of the lower Columbia River.