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NOAA-NMFS-NWFSC TM-33: Sockeye Salmon Status Review (cont)
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ASSESSMENT OF EXTINCTION RISK

Background

As outlined previously in the "Introduction," NMFS considers a variety of information in evaluating the level of risk facing an ESU. Aspects of several of these risk considerations are common to all sockeye salmon ESUs. These are discussed in general below; more specific discussion of factors for each of the ESUs under consideration here can be found in the following sections. Because we have not taken future effects of conservation measures into account (see "Introduction"), we have drawn scientific conclusions about the risk of extinction faced by identified ESUs under the assumption that present conditions will continue. Future effects of conservation measures will be taken into account by the NMFS Northwest Regional Office in making listing recommendations.

Absolute Numbers

The absolute number of individuals in a population is important in assessing two aspects of extinction risk. For small populations that are stable or increasing, population size can be an indicator of whether the population can sustain itself into the future in the face of environmental fluctuations and small-population stochasticity; this aspect is related to the concept of minimum viable populations (MVP) (see Gilpin and Soulé 1986, Thompson 1991). For a declining population, the present abundance is an indicator of the expected time until the population reaches critically low numbers; this aspect is related to the concept of "driven extinction" (Caughley 1994). In addition to total numbers, the spatial and temporal distribution of adults is important in assessing risk to an ESU. Spatial distribution is important both at the scale of lake or river basins and at the scale of spawning areas within basins ("metapopulation" structure). Temporal distribution is important both among years, as an indicator of the relative health of different brood-year lineages, and within seasons, as an indicator of the relative abundance of different life-history types or runs.

Traditionally, assessment of salmonid populations has focused on the number of harvestable and/or reproductive adults, and these measures comprise most of the data available for Pacific salmon and steelhead. In assessing the future status of a population, the number of reproductive adults is the most important measure of abundance, and we focus here on measures of the number of adults escaping to spawn in natural habitat. However, total run size (spawning escapement + harvest) is also of interest because it indicates potential spawning in the absence of harvest. Data on other life-history stages (e.g., freshwater smolt production) can be used as a supplemental indicator of abundance.

Because the ESA (and NMFS policy) mandates that we focus on viability of natural populations, in this review we attempted to distinguish natural fish from hatchery-produced fish. All statistics are based on data that indicate total numbers or density of adults that spawn in natural habitat ("naturally spawning fish"). The total of all naturally spawning fish ("total escapement") is divided into two components (Fig. 14): "Hatchery produced" fish are reared as juveniles in a hatchery but return as adults to spawn naturally; "Natural" fish are progeny of naturally spawning fish.

Historical Abundance and Carrying Capacity

The relationship of current abundance and habitat capacity to that which existed historically is an important consideration in evaluating risk for several reasons. Knowledge of historical population conditions provides a perspective of the conditions under which present stocks evolved. Historical abundance also provides the basis for establishing long-term trends in populations. Comparison of present and past habitat capacity can also indicate long-term population trends and problems of population fragmentation.

Although the relationship of present abundance to present carrying capacity is important for understanding the health of populations, the fact that a population is near its current capacity does not in itself mean that it is healthy. If a population is near capacity, there will be limits to the effectiveness of short-term management actions in increasing abundance, and competition and other interactions between hatchery and natural fish may be an important consideration because hatchery fish will further increase population density in a limited habitat.

All populations of sockeye salmon in this region have been affected by substantial loss and degradation of freshwater habitat, although the causes vary among populations. Much of the original sockeye salmon habitat in the Columbia River Basin has been blocked by irrigation diversions, hydroelectric development, and other human actions: accessible nursery lake habitat in the upper Columbia River is now only 4% (by surface area) of historical habitat, and only one remnant population remains in the Snake River (Mullan 1986, TAC 1991, Fryer 1995). This has resulted in widespread extinctions of populations that formerly occupied these areas. Coastal populations have also been affected by a variety of habitat factors, particularly hydroelectric development (Baker River) and forest management practices.

Trends in Abundance

Short- and long-term trends in abundance are a primary indicator of risk in salmonid populations. Trends may be calculated from a variety of quantitative data, including dam or weir counts, stream surveys, and catch data. These data sources and methods are discussed in more detail below (see "Approach").

The important role of artificial propagation (in the form of hatcheries) for Pacific salmon requires careful consideration in ESA evaluations. Artificial propagation has implications for evaluating both production trends and the genetic integrity of populations. Waples (1991a, b) and Hard et al. (1992) discussed the role of artificial propagation in ESU determination and emphasized the need to focus on natural production in the threatened or endangered status determination. A fundamental question in ESA risk assessments for mixed-production stocks is whether natural production is sufficient to maintain the population without the continued infusion of artificially produced fish. A full answer to this question is difficult without extensive studies of relative production and interactions between hatchery and natural fish. When such information is lacking, the presence of hatchery fish in natural populations leads to substantial uncertainty in evaluating the status of the natural population.

Long-term trends in abundance of sockeye salmon in the Pacific Northwest can only be approximated from historical records of commercial fishery landings (Fig. 15). However, these trends largely reflect the harvest of Fraser River sockeye salmon in British Columbia and Washington, and therefore do not provide a good indication of the status of ESUs we are considering here. To the extent that landings reflect population abundance, these records suggest fairly constant populations of sockeye salmon in this region except for large short-term fluctuations (discussed in the next section). Harvest was somewhat higher near the turn of the century than during 1920-1980, and increasing harvest in British Columbia since 1980 has restored harvest levels to near those of the early 1900s.

A major determinant of trends in salmon abundance is the condition of the freshwater, estuarine, and ocean habitats on which salmon depend. While we rarely have sufficient information to precisely predict the population-scale effects of habitat loss or degradation, it is clear that habitat availability imposes an upper limit on the production of salmon, and any reduction in habitat reduces potential production. Even in areas where we have no information on trends in population abundance, evidence of widespread loss of habitat can indicate a serious risk for sustainability of natural populations.

The National Research Council Committee on Protection and Management of Pacific Northwest Anadromous Salmonids (NRCC 1996) identified habitat problems as a primary cause of declines in wild salmon runs. NMFS (1996) identified habitat concerns as one of a suite of factors affecting the decline of salmon within the range of west coast steelhead. Some of the habitat impacts identified were: 1) the fragmentation and loss of available spawning and rearing habitat; 2) alteration of stream flows and stream-bank and channel morphology; 3) migration delays; 4) degradation of water quality; 5) alteration of ambient stream water temperatures; 6) sedimentation; 7) loss of spawning gravels, pool habitat and large woody debris; 8) removal of riparian vegetation; and 9) decline of habitat complexity.

The Pacific Fishery Management Council (PFMC 1995) also identified loss of habitat as one of the main reasons for declines in salmon stocks and identified fourteen "vital habitat concerns." Their concerns relative to sockeye salmon are Columbia-Snake River hydropower operations, instream flow, unscreened or inadequately screened water diversions, inadequate fish passage at road culverts, water spreading (unauthorized use of federally-developed water supplies), upland land-use practices and polluted runoff, fish passage at existing hydroelectric projects, agricultural practices, urban growth and land conversion, contaminants in coastal wetlands and estuaries, offshore oil and gas development and transportation, and dredge spoil disposal.

Assessing the effects of habitat changes on future sustainability of populations is difficult. Human populations are projected to continue increasing in most areas of the west coast, and water impoundments and diversions, as well as logging and agricultural activities, will continue into the future. These facts indicate that there will be some continuing losses of salmon habitat in the foreseeable future. Balancing this, recent changes in forest and agricultural practices and improved urban planning have reduced the rate of habitat loss in many areas, and many areas are recovering from severe past degradation. Whether natural recovery and active restoration in some areas will compensate for continued losses in other areas is unknown.

Factors Causing Variability

Abundance of sockeye salmon populations tends to fluctuate around a general level, either displaying predictable cyclic fluctuations or unexpected upward or downward changes (Burgner 1991). In some populations, a large part of this variability is attributable to the phenomenon of brood-cycle dominance, which is the tendency of single year-classes to consistently dominate abundance trends in populations that return to spawn largely at a single age (Ricker 1950, Ward and Larkin 1964, Eggers and Rogers 1987). This phenomenon was seen in the 1901-brood cycle of sockeye salmon in the Fraser River in the early 1900s (Fig. 15), which clearly displayed dominance. This pattern in the overall Fraser River run was disrupted by the Hells Gate slide, but is still apparent in the abundance trends of individual Fraser River stocks. Ricker (1997) reviewed cycles in Fraser River sockeye salmon, and suggested that interactions among dominant and other brood lines are the most plausible cause of the cycles. Brood-cycle dominance is less evident in the U.S. populations we are considering here, possibly because spawning age-structure is more variable in most of these populations or because relative abundance has not been high enough to establish the pattern. Where it occurs, however, cyclic dominance could be a major influence in abundance analysis and recovery planning.

Variations in the freshwater and marine environments are also thought to be a primary factor driving fluctuations in salmonid run size and escapement (Pearcy 1992, Beamish and Bouillon 1993, Lawson 1993). Recent changes in ocean conditions are an additional factor and are discussed in the "Recent Events" section. Habitat degradation and harvest have probably made stocks less resilient to poor climate conditions, but these effects are not easily quantifiable.

Threats to Genetic Integrity

In addition to being a factor in evaluating natural replacement rates, artificial propagation can have a substantial impact on genetic integrity of natural salmon and steelhead populations. This can occur in several ways. First, stock transfers that result in interbreeding of hatchery and natural fish can lead to loss of fitness in local populations and loss of diversity among populations. The latter is important to maintaining long-term viability of an ESU because genetic diversity among salmonid populations helps to buffer overall productivity against periodic or unpredictable changes in the environment (Riggs 1990, Fagen and Smoker 1989). Ricker (1972) and Taylor (1991) summarized some of the evidence for local adaptations in Pacific salmonids that may be affected by stock transfers.

Second, because a successful salmon hatchery dramatically changes the mortality profile of a population, some level of genetic change relative to the wild population is inevitable even in hatcheries that use local broodstock (Waples 1991b). These changes are unlikely to be beneficial to naturally reproducing fish.

Third, even if naturally spawning hatchery fish leave few or no surviving offspring, they still can have ecological and indirect genetic effects on natural populations. On the spawning grounds, hatchery fish may interfere with natural production by competing with natural fish for territory and/or mates. If they successfully spawn with natural fish, they may divert production from more productive natural x natural crosses. The presence of large numbers of hatchery juveniles or adults may also alter the selective regime faced by natural fish.

Not all of these concerns will apply to every hatchery population, and the seriousness of the concerns that do apply can vary considerably among different programs. For example, although stock transfers are a major issue for some hatchery programs, many others have exclusively used local broodstock. Some hatchery programs have also taken a number of measures (e.g., in broodstock collection, spawning, rearing, and release protocols) to minimize adverse effects on natural populations. Therefore, threats posed by hatchery programs should be evaluated on a case­by­case basis whenever available data allow such an evaluation. It should be recognized, however, that some changes associated with fish culture cannot be avoided, and some risks are also inescapable because they involve a trade­off with other risks. For example, changing the hatchery environment to more closely mimic selective regimes faced in the wild can reduce opportunities for domestication, but there is a limit to how far this process can go without sacrificing the early life history survival advantage that is the primary benefit of a salmon hatchery. Similarly, although releasing hatchery fish as smolts reduces opportunities for ecological interactions with natural fish, it also increases opportunities for genetic change associated with fish culture compared to releases at an earlier life history stage.

For smaller salmon stocks (either natural or hatchery), small-population effects (inbreeding, genetic drift) can also be important concerns for genetic integrity. Inbreeding and genetic drift are well understood at the theoretical level, and researchers have found inbreeding depression in various fish species (reviewed by Allendorf and Ryman 1987). Other studies (e.g., Simon et al. 1986, Withler 1988, Waples and Teel 1990) have shown that hatchery practices commonly used with anadromous Pacific salmonids have the potential to affect genetic integrity. However, we have not found empirical evidence for inbreeding depression or loss of genetic variability in any natural or hatchery populations of Pacific salmon.

Recent Events

A variety of factors, both natural and human-induced, affect the degree of risk facing salmonid populations. Because of time-lags in these effects and variability in populations, recent changes in any of these factors may affect current risk without any apparent change in available population statistics. Thus, consideration of these effects must go beyond examination of recent abundance and trends. However, forecasting future effects is rarely straightforward and usually involves qualitative evaluations based on informed professional judgement. Events affecting populations may include natural changes in the environment or human-induced changes, either beneficial or detrimental. Possible future effects of recent or proposed conservation measures have not been taken into account in this analysis, but we have considered documented changes in the natural environment. A key question regarding the role of recent events is: Given our uncertainty regarding the future, how do we evaluate the risk that a population may not persist?

For example, climate conditions are known to have changed recently in the Pacific Northwest, and Pacific salmon stocks south of British Columbia have been affected by changes in ocean production that occurred during the 1970s (Pearcy 1992, Lawson 1993). There is mounting evidence that salmon populations are influenced by decadal-scale shifts in climate patterns; such effects were discussed at a recent workshop sponsored by NMFS and Oregon State University (Emmett and Schiewe 1997). Beamish et al. (1997) have related production of Fraser River sockeye salmon to decadal-scale shifts in ocean productivity. Much of the Pacific coast has also been experiencing drought conditions in recent years, which may depress freshwater production. However, at this time we do not know whether these climate conditions represent a long-term change that will continue to affect stocks in the future or whether these changes are short-term environmental fluctuations that can be expected to be reversed in the near future.

Other Risk Factors

Other risk factors typically considered for salmonid populations include disease prevalence, predation, and changes in life history characteristics such as spawning age or size.

Approach

Previous Assessments

In considering the status of the ESUs, we evaluated both qualitative and quantitative information. Qualitative evaluations included aspects of several of the risk considerations outlined above, as well as recent published assessments of population status by agencies or conservation groups of the status of west coast sockeye salmon stocks (Nehlsen et al. 1991, WDF et al. 1993). Nehlsen et al. (1991) considered salmonid stocks throughout Washington, Idaho, Oregon, and California and enumerated all stocks that they found to be extinct or at risk of extinction. Stocks that do not appear in their summary were either not at risk of extinction or were not classifiable due to insufficient information. They classified stocks as extinct, possibly extinct, at high risk of extinction, at moderate risk of extinction, or of special concern. They considered it likely that stocks at high risk of extinction have reached the threshold for classification as endangered under the ESA. Stocks were placed in this category if they had declined from historic levels and were continuing to decline, or had spawning escapements less than 200. Stocks were classified as at moderate risk of extinction if they had declined from historic levels but presently appear to be stable at a level above 200 spawners. They felt that stocks in this category had reached the threshold for threatened under the ESA. They classified stocks as of special concern if a relatively minor disturbance could threaten them, insufficient data were available for them, they were influenced by large releases of hatchery fish, or they possessed some unique character. For sockeye salmon, they classified 22 stocks as follows: 16 extinct, 1 possibly extinct, 2 high risk, 1 moderate risk, and 2 special concern (Table 4).

WDF et al. (1993) categorized all salmon and steelhead stocks in Washington on the basis of stock origin ("native," "non-native," "mixed," or "unknown"), production type ("wild," "composite," or "unknown") and status ("healthy," "depressed," "critical," or "unknown"). Status categories were defined as follows: healthy, "experiencing production levels consistent with its available habitat and within the natural variations in survival for the stock"; depressed, "production is below expected levels . . . but above the level where permanent damage to the stock is likely"; and critical, "experiencing production levels that are so low that permanent damage to the stock is likely or has already occurred." Of the nine sockeye salmon stocks identified, three (Quinault, Wenatchee, and Okanogan) were classified as healthy, four (Cedar, Lake Washington/Sammamish Tributaries, Lake Washington Beach, and Ozette) as depressed, one (Baker) as critical, and one (Lake Pleasant) as unknown.

There are problems in applying results of these studies to ESA evaluations. One problem is the definition of categories used to classify stock status. Nehlsen et al. (1991) used categories intended to relate to ESA "threatened" or "endangered" status; however they applied their own interpretations of these terms to individual stocks, not to ESUs as defined here. WDF et al. (1993) used general terms describing status of stocks that cannot be directly related to the considerations important in ESA evaluations. For example, the WDF et al. (1993) definition of healthy could conceivably include a stock that is at substantial extinction risk due to loss of habitat, hatchery fish interactions, and/or environmental variation, although this does not appear to be the case for any west coast sockeye salmon stocks. Another problem is the selection of stocks or populations to include in the review. Nehlsen et al. (1991) did not evaluate (or even identify) stocks not perceived to be at risk, so it is difficult to determine the proportion of stocks they considered to be at risk in any given area. There is also disagreement regarding status of some stocks; for example, IDFG (1996) disagrees with the classification of Alturas and Stanley Lakes' populations as extinct by Nehlsen et al. (1991).

Data Evaluations

Quantitative evaluations of data included comparisons of current and historical abundance of west coast sockeye salmon, calculation of recent trends in escapement, and evaluation of the proportion of natural spawning attributable to hatchery fish. Historical abundance information for these ESUs is largely anecdotal, although estimates based on commercial harvest are available for some coastal populations (Rounsefell and Kelez 1938).

Time series data were available for many populations, but data extent and quality varied among ESUs. We compiled and analyzed this information to provide several summary statistics of natural spawning abundance, including (where available) recent total spawning run-size and escapement, percent annual change in total escapement, recent naturally produced spawning run-size and escapement, and average percentage of natural spawners that were of hatchery origin. Information on harvest and stock abundance was compiled from a variety of state, federal, and tribal agency records (Foy et al. 1995a, b). Additional data were provided directly to us by state and tribal agencies and private organizations. We believe these records to be complete in terms of long-term adult abundance for sockeye salmon in the region covered. Principal data sources were adult counts at dams or weirs and spawner surveys.

Computed statistics

To represent current run size or escapement where recent data were available, we have computed the geometric mean of the most recent 5 years reported (or fewer years if the data series is shorter than 5 years). We tried to use only estimates that reflect the total abundance for an entire river basin or tributary, avoiding index counts or dam counts that represent only a small portion of available habitat.

Where adequate data were available, trends in total escapement (or run-size if escapement data were not available) were calculated for all data sets with more than 7 years of data, based on total escapement or an escapement index (such as fish per mile from a stream survey). Separate trends were estimated for each full data series and for the 1985-1994 period within each data series. As an indication of overall trend in individual sockeye salmon populations, we calculated average (over the available data series) percent annual change in adult spawner indices within each river basin. Trends were calculated as the slope (a) of the regression of ln(abundance) against years corresponding to the biological model N(t) = beat. Slopes significantly different from zero (P<0.05) were noted. The regressions provided direct estimates of mean instantaneous rates of population change (a); these values were subsequently converted to percent annual change, calculated as 100(ea - 1). No attempt was made to account for the influence of hatchery produced fish on these estimates, so the estimated trends include any supplementation effect of hatchery fish.

These computed statistics, along with published estimates of historical abundance and results of previous status assessments, are summarized in Appendix Table E-1 for all stocks examined in this review.

Analysis of Biological Information by ESU

1) Okanogan River

The major abundance data series for Okanogan River sockeye salmon consists of spawner surveys conducted in the Okanogan River above Lake Osoyoos since the late 1940s, counts of adults passing Wells Dam since 1967, and records of tribal harvest (Colville and Okanogan) since the late 1940s. Longer-term data were available for dams lower on the Columbia River (notably Rock Island Dam counts starting in 1933), but these counts represent a combination of this ESU with the Wenatchee populations and other historical ESUs from the upper Columbia River above Grand Coulee Dam.

Blockage and disruption of freshwater habitat pose some risk for this ESU. Adult passage is blocked by dams above Lake Osoyoos, prohibiting access to former habitat in Vaseux, Skaha, and Okanagan Lakes (Chapman et al. 1995). (However, it is not known whether sockeye salmon in these upper lakes belonged to the same ESU as those in Lake Osoyoos.) Other problems in the Okanogan River include inadequately screened water diversions and high summer water temperatures (Chapman et al. 1995), and channelization of spawning habitat in Canada. Mullan (1986) stated that hydroelectric dams accounted for the general decline of sockeye salmon in the mainstem Columbia River, while Chapman et al. (1995) suggested that hydropower dams have "probably" reduced runs of sockeye salmon to the Columbia River, particularly to Lake Osoyoos.

The most recent 5-year average annual escapement for this ESU was about 11,000 adults, based on 1992-1996 counts at Wells Dam (see Appendix Table E-1). No historic abundance estimates specific to this ESU are available. However, analyses conducted in the late 1930s indicated that less than 15% of the total sockeye run in the upper Columbia River went into Lakes Osoyoos and Wenatchee (Chapman et al. 1995). At that time, the total run to Rock Island Dam averaged about 15,000, suggesting a combined total of less than 2,250 adults returning to the Okanogan River and Lake Wenatchee ESUs. Thus, abundance for the Okanogan River ESU during the late 1930s was clearly substantially lower than recent abundance. Trend estimates for this stock differ depending on the data series used (see Appendix Table E-1), but the recent (1986-1995) trend has been steeply downward (declining at 2-20% per year); however, this trend is heavily influenced by high abundance in 1985 and low points in 1990, 1994, and 1995, which may reflect environmental fluctuations (Fig. 17). The long-term trend (since 1960) for this stock has been relatively flat (-3% to +2% annual change).

For the entire Columbia River basin, there has been a considerable decline in sockeye salmon abundance since the turn of the century. Columbia River commercial sockeye salmon landings that commonly exceeded 1,000,000 pounds in the late 1800s and early 1900s had been reduced to about 150,000 pounds by the late 1980s (TAC 1991). Since 1988, harvest has been fewer than 3,500 fish each year. The TAC (1991) attributes this decline to habitat degradation and blockage, overharvest, hydroelectric development, and nursery lake management practices. The two remaining productive stocks (Okanogan and Wenatchee) occupy less than 4% of historic nursery lake habitat in the upper Columbia River basin.

Both Okanogan and Wenatchee runs have been highly variable over time. For harvest purposes, these two ESUs are managed as a single unit, with an escapement goal of 65,000 adults returning to Priest Rapids Dam (TAC 1991). This goal has been achieved only ten times since 1970, and has been met in 2 of the last 5 years. Examination of the historical trend in total sockeye salmon escapement to the upper Columbia River (Fig. 16) shows very low abundance (averaging less than 20,000 annually) during the 1930s and early 1940s, followed by an increase to well over 100,000 per year in the mid-1950s. Since the mid-1940s, abundance has fluctuated widely, with noticeable low points reached in 1949, 1961-62, 1978, and 1994. The escapement of about 9,000 fish to Priest Rapids Dam in 1995 was the lowest since 1945, but 1996 escapement (preliminary estimate, Fish Passage Center 1996) was considerably higher, although still far below the goal. Escapement to Wells Dam (i.e., this ESU) was at its lowest recorded value in 1994, but increased in both 1995 and 1996.

Past and present artificial propagation of sockeye salmon poses some risk to the genetic integrity of this ESU. The GCFMP (discussed in the "Artificial Propagation" section above) interbred fish from this ESU with those from adjacent basins for several years, with unknown impacts on the genetic composition of this ESU. Current artificial propagation efforts use local stocks and are designed to maintain genetic diversity, but there is some risk of genetic change resulting from domestication. There is only one record of introduction of sockeye salmon from outside the Columbia River Basin into this ESU: 395,420 mixed Quinault Lake/Rock Island Dam stock released in 1942 (Mullan 1986) (see Appendix Table D-2). Records of kokanee transplants are most likely incomplete (see Appendix Table D-5).

In previous assessments of this stock, Nehlsen et al. (1991) considered Okanogan River sockeye salmon to be of special concern because of "present or threatened destruction, modification, or curtailment of its habitat or range," including mainstem passage, flow, and predation problems. While WDF et al. (1993) classified this stock as of native origin, wild production, and healthy status they also suggested that this "native" classification will be changed to "mixed" in the future (WDFW 1996).

2) Lake Wenatchee

The major abundance data series for Wenatchee River sockeye salmon consists of spawner surveys conducted in the Little Wenatchee River and the White River since the late 1940s, counts of adults passing Tumwater Dam (sporadic counts 1935 to present), and reconstructions based on adult passage counts at Priest Rapids, Rock Island, and Rocky Reach Dams (early 1960s to present). Longer-term data are available for dams lower on the Columbia River (notably Rock Island Dam counts starting in 1933), but these counts represent a combination of this ESU with the Okanogan River ESU and other historic potential ESUs from the upper Columbia River above Grand Coulee Dam.

There are no substantial blockages of sockeye salmon habitat in the Wenatchee basin, and habitat condition in the basin is generally regarded as good, although production is limited by the oligotrophic nature of Lake Wenatchee (Chapman et al. 1995). Mullan (1986) and Chapman et al. (1995) concluded that the main freshwater-habitat problem presently facing this ESU is hydropower dams in the mainstem Columbia River, which have probably reduced runs of sockeye salmon.

The most recent 5-year average annual escapement for this ESU was about 19,000 adults, based on the 1992-1996 difference in adult passage counts at Priest Rapids and Rocky Reach Dams (see Appendix Table E-1). No historic abundance estimates specific to this ESU are available. However, as discussed above for the Okanogan River ESU, abundance of the Lake Wenatchee ESU during the late 1930s was clearly substantially lower than recent abundance. The recent (1986-1995) trend in abundance has been downward (declining at 10% per year), but this trend was heavily influenced by 2 years of very low abundance in 1994 and 1995 (Fig. 17). The long-term (1961-1996) trend for this stock is flat. Escapement to this ESU in 1995 (counts at Priest Rapids Dam minus those at Rocky Reach Dam) was the lowest since counting began in 1962, but 1996 escapement was somewhat higher (Fig. 17). Other risk factors common to this ESU and other Columbia River Basin sockeye salmon populations were discussed under the Okanogan River ESU above.

Past and present artificial propagation of sockeye salmon poses some risk to the genetic integrity of this ESU. As for the Okanogan River ESU, the GCFMP interbred fish from this ESU with those from adjacent basins for several years and introduced many sockeye salmon descended from Quinault Lake stock (Mullan 1986) (Appendix D-2), with unknown impacts on the genetic composition of this ESU. Current artificial propagation efforts use local stocks and are designed to maintain natural genetic diversity, but there is some risk of genetic change resulting from domestication. Hatchery-raised kokanee have been released in Lake Wenatchee, including native Lake Wenatchee stock and nonnative Lake Whatcom stock (Mullan 1986) (see Appendix Table D-5). The effect of Lake Whatcom kokanee introductions on the genetic integrity of this ESU is unknown.

Previous assessments of this ESU are similar to those for the Okanogan River ESU. Nehlsen et al. (1991) considered Wenatchee River sockeye salmon to be of special concern because of "present or threatened destruction, modification, or curtailment of its habitat or range," including mainstem passage, flow, and predation problems. WDF et al. (1993) classified this stock as of mixed origin, wild production, and healthy status. Huntington et al. (1996) identified this stock as "healthy-Level I," indicating that current abundance is high relative to what would be expected without human impacts.

3) Quinault Lake

The major abundance data series for Quinault River sockeye salmon consists of escapement estimates derived from hydroacoustic surveys conducted in Quinault Lake since the mid-1970s, supplemented with earlier estimates (beginning in 1967) based on spawner surveys. The most recent (1991-1995) 5-year average annual escapement for this ESU was about 32,000 adults, with a run-size of about 39,000 (see Appendix Table E-1 and Fig. 18). Approximate historical estimates indicate escapements ranging between 20,000 and 250,000 in the early 1920s, and run sizes ranging between 50,000 and 500,000 in the early 1900s (Rounsefell and Kelez 1938). Comparison of these estimates indicates that recent abundance is probably near the lower end of the historical abundance range for this ESU.

This ESU has been substantially affected by habitat problems, notably those resulting from forest management activities in the upper watershed outside Olympic National Park. Early inhabitants of the area described the upper Quinault River as flowing between narrow, heavily-wooded banks, but by the 1920s the river was in a wide valley with frequent course changes and much siltation and scouring of gravels during winter and spring freshets (Davidson and Barnaby 1936, QIN 1981); resultant loss of spawning habitat in the Quinault River above Quinault Lake has continued to recent times (QIN 1981).

While stock abundance has fluctuated considerably over time (recent escapements ranging from a low of 7,500 in 1970 to 69,000 in 1968), the overall trend has been relatively flat. For the full data series (1967-1995), abundance has increased by an average of about 1% per year; for the 1986-1995 period, abundance declined by about 3% per year.

Artificial propagation of sockeye salmon in the Quinault River basin has a long history (see "Artificial propagation" section above). Releases have been primarily native Quinault Lake stock, although Alaskan sockeye salmon eggs were brought into the system prior to 1920 (see Appendix Tables D-1 and D-2). Genetic effects of this introduction are unknown. Since 1973, all releases have been of local stock, but there is some risk of genetic change resulting from unnatural selective pressures.

In previous assessments, Nehlsen et al. (1991) did not identify Quinault Lake sockeye salmon as at risk, and WDF et al. (1993) classified this stock as of native origin, wild production, and healthy status.

4) Ozette Lake

The major abundance data series for Ozette River sockeye salmon consists of escapement estimates derived from counts at a weir located at the outlet of Ozette Lake. Counting has occurred in most years since 1977 (Dlugokenski et al. 1981, WDF et al. 1993). The most recent (1992-1996) 5-year average annual escapement for this ESU was about 700 adults (see Appendix Table E-1). Historical estimates indicate run sizes of a few thousand sockeye salmon in 1926 (Rounsefell and Kelez 1938), with a peak recorded harvest of nearly 18,000 in 1949 (WDF 1974). Subsequently, commercial harvest declined steeply to only a few hundred fish in the mid-1960s and was ended in 1974. A small ceremonial and subsistence fishery continued until 1981 (Dlugokenski et al. 1981); there has been no direct fishery on this stock since 1982 (WDF et al. 1993). Assuming that Ozette River harvest consisted of sockeye salmon destined to spawn in this system, comparison of these estimates indicates that recent abundance is substantially below the historical abundance range for this ESU.

Three studies have been undertaken to evaluate habitat-related factors limiting production of sockeye salmon in Ozette Lake. The U.S. Fish and Wildlife Service conducted studies of the decline in this stock during the 1970s, culminating in a report describing limiting factors and outlining a restoration plan (Dlugokenski et al. 1981). This report noted that this population formerly spawned in tributaries but presently only uses the lakeshore, and that food supply, competition, and predation in the lake are probably not limiting, but that siltation has caused cementing of spawning gravels in tributaries. Dlugokenski et al. (1981) suspected that sedimentation, resulting primarily from logging and associated road building, coupled with log truck traffic on weak siltstone roadbeds, have led to decreased hatching success of sockeye salmon in tributary creeks and creek outwash fans in Ozette Lake. The authors concluded that "a combination of overfishing and habitat degradation have reduced the sockeye population to its current level of less than 1,000 fish" (p. 43).

More recently, Blum (1988) conducted an assessment of the same problems and concluded that "the absence of tributary spawners is the paramount problem explaining why sockeye runs have not increased following the cessation of terminal-area fishing in 1973." He cited three main problems related to road-building and logging that limit spawning habitat: increased magnitude and frequency of peak flows, stream-bed scouring, and degraded water quality. He also noted that "the logging of the watershed was so extensive that stream spawning and rearing conditions are still questionable, despite having 35 years to recover" (p. 1). Finally, Beauchamp et al. (1995) examined patterns of prey, predator, and competitor abundance in Ozette Lake as potential limiting factors for juvenile production of sockeye salmon and kokanee. They concluded that competition is unlikely to limit production but that predation could be a limiting factor; however, data on piscivore abundance were lacking, so the authors could not evaluate predation impact accurately.

A recent National Park Service Technical Report (Jacobs et al. 1996) reported the conclusions of a review panel concerning the status and management of sockeye salmon in Ozette Lake. The panel was unanimous in expressing great concern about the future of this population, but was unable to identify a single set of factors contributing to the population decline. The panel concluded that declines were likely the result of a combination of factors, possibly including introduced species, predation, loss of tributary populations, decline in quality of beach-spawning habitat, temporarily unfavorable oceanic conditions, excessive historical harvests, and introduced diseases. They felt that intra- and inter-specific competition was unlikely as a contributing factor.

Harvest of sockeye salmon in the Ozette River fluctuated considerably over time (Fig. 19), which would indicate similar fluctuations in spawner abundance if harvest rates were fairly constant. Based on the full weir-count series (1977-1995), abundance has decreased by an average of about 3% per year; for the 1986-1995 period the decrease averaged 10% per year. However, in recent years the stock has exhibited dominance by a single brood cycle returning every 4 years (1984, 1988, 1992, 1996), and this dominant cycle has remained stable at between 1,700 and 2,200 adults; declines are apparent only in the smaller returns during off-cycle years (Fig. 19).

Artificial propagation has not been extensive in this basin, but many of the releases have been non-indigenous stocks (see "Artificial Propagation" section). Genetic effects of these introductions are unknown. Recent hatchery production in Ozette Lake has been primarily from local stock, with the exception of 120,000 Quinault Lake sockeye salmon juveniles released in 1983. The release of 14,398 kokanee/sockeye salmon hybrids in 1991-1992 (MFMD 1995, NRC 1995) may have had deleterious effects on genetic integrity of the ESU because Ozette Lake kokanee are genetically dissimilar to Ozette Lake sockeye salmon (see above "Genetics" section).

In previous assessments, Nehlsen et al. (1991) identified Ozette sockeye salmon as at moderate risk of extinction, citing logging and overfishing in the 1940s and 1950s as major causes of the decline. WDF et al. (1993) classified this stock as of native origin, wild production, and depressed status.

5) Baker River

The major abundance data series for Baker River sockeye salmon consists of escapement estimates derived from counts of adults arriving at a trap below Lower Baker Dam beginning in 1926 (Fig. 20). The most recent 5-year average annual escapement for this ESU was about 2,700 adults (see Appendix Table E-1). Historical estimates indicate escapements averaging 20,000 near the turn of the century, with a pre-dam low of 5,000 in 1916 (Rounsefell and Kelez 1938), although WDFW data suggest that the 20,000 figure is a peak value, not an average (Sprague 1996a). Comparison of these estimates indicates that recent average abundance is probably near the lower end of the historical abundance range for this ESU, although escapement in 1994 (16,000 fish) was near the turn-of-the-century average.

Currently, spawning is restricted to artificial spawning "beaches" at the upper end of Baker Lake (in operation since 1957) and just below Upper Baker Dam (beach constructed in 1990). Spawning on the beaches is natural, and fry are released to rear in Baker Lake. Before 1925, sockeye salmon had free access to Baker Lake and its tributaries. Lower Baker Dam (constructed 1925) blocked access to this area, but passage structures were provided. Upper Baker Dam was completed in 1959 and increased the size of Baker Lake, inundating most natural spawning habitat; this was mitigated by construction of artificial spawning beaches. In most years, all returning adults are trapped below Lower Baker Dam and transported to the artificial beaches, with no spawning occurring in natural habitat (WDF et al. 1993). The only recent exception to this was in 1994, when the large number of returning adults exceeded artificial habitat capacity, and excess spawners were allowed to enter Baker Lake and its tributaries (J. Ames58). At the time of this report, no quantitative reports regarding offspring resulting from this spawning "experiment" are available (WDFW 1996).

The artificial nature of spawning habitat, use of net-pens for juvenile rearing, and reliance on artificial upstream and downstream transportation poses a certain degree of risk to the ESU. These human interventions in the life-cycle have undoubtedly changed selective pressures on the population from those under which it evolved its presumably unique characteristics, and thus pose some risk to the long-term evolutionary potential of the ESU. There have been continuing potential problems with siltation at the newer (lower) spawning beach (WDF et al. 1993), and recent proposals to close the two upper beaches in favor of production at the lower beach would thus be likely to increase risk of spawning failure in some years. The future use of the upper beaches is uncertain (WDFW 1996). Problems with operations of downstream smolt bypass systems have been documented, and there may be limitations to juvenile sockeye production due to inadequate lake productivity and interactions with other salmonids (WDF et al. 1993). IHN has also been a recent problem for this stock (G. Sprague59).

While stock abundance has fluctuated considerably over time (recent escapements ranging from a low of about 100 in 1985 to 16,000 in 1994), the long-term trend has been relatively flat. For the full data series (1926-1995), abundance has decreased by an average of about 2% per year; for the 1986-1995 period, abundance increased by about 32% per year.

Artificial production in this ESU began in 1896 with a state hatchery on Baker Lake; hatchery efforts at Baker Lake ended in 1933, by which time the hatchery was being operated by the U.S. Bureau of Fisheries (see "Artificial Propagation" section, WDF et al. 1993). Current propagation efforts rely primarily on the spawning beaches and net-pen rearing. Lake Whatcom kokanee were recently introduced to Lake Shannon (Knutzen 1995). Genetic consequences of these releases and rearing programs are unknown, but there is some risk of genetic change resulting from unnatural selective pressures.

In previous assessments, Nehlsen et al. (1991) identified Baker River sockeye salmon as at high risk of extinction, and WDF et al. (1993) classified this stock as of native origin, artificial production, and critical status.

6) Lake Pleasant

Although no recent complete escapement estimates are available for this stock, we recently have received some spawner-survey data for the period 1987 to 1996 (Mosley 1995, Tierney 1997). Peak spawner counts ranged from a low of 90 (1991-a year with limited sampling) to highs above 2,000 (1987 and 1992). Abundance fluctuated widely during this period, with a slight negative trend overall.

Complete counts at a trapping station on Lake Creek in the early 1960s showed escapements of sockeye salmon ranging from 763 to 1,485 fish, and 65,000 sockeye salmon smolts were reported to have outmigrated in 1958 (Crutchfield et al. 1965). This stock supports small sport and tribal commercial fisheries, with probably fewer than 100 fish caught per year in each fishery (WDF et al. 1993). Sockeye salmon from Grandy Creek stock were released in 1933 and 1937; no sockeye salmon have been introduced since then (see "Artificial Propagation" section above).

In previous assessments, Nehlsen et al. (1991) did not identify Lake Pleasant sockeye salmon as at risk, and WDF et al. (1993) classified this stock as of native origin, wild production, and unknown status.

Analysis of Biological Information for Provisional ESU

Big Bear Creek

Abundance data for Big Bear Creek sockeye salmon are derived from spawner surveys conducted by WDFW from 1982 to the present (WDF et al. 1993, J. Ames60). The most recent (1991-1995) 5-year average annual escapement for this unit was about 11,400 adults (see Appendix Table E-1). No historical estimates are available, but comparing habitat areas in these basins with other sockeye salmon populations suggests that current production is probably a substantial proportion of freshwater habitat capacity. Habitat in this basin is subject to effects of urbanization.

Stock abundance has fluctuated considerably over time, with recent escapements ranging from a low of 1,800 in 1989 to 39,700 in 1994. There has been little overall trend in this unit; for the full data series (1982-1995), abundance has decreased by an average of about 7% per year; for the 1986-1995 period, abundance decreased approximately 4% per year. 1995 escapement was the second lowest on record, but 1994 was the highest.

Releases of non-native sockeye salmon in this area have occurred on Big Bear and North Creek (tributaries of the Sammamish River), using Grandy Creek stock from the Skagit River and Cultus Lake stock from British Columbia, respectively (see Appendix Table D-2). There have been extensive introductions of kokanee in this area, a substantial proportion of which were from Lake Whatcom. Genetic interactions of these kokanee with sockeye salmon are unknown.

In previous assessments, Nehlsen et al. (1991) did not identify this stock as at risk, and WDF et al. (1993) classified this stock as of unknown origin, wild production, and depressed status.

Analysis of Biological Information for Other Population Units

While the units discussed below are not presently considered to constitute ESUs, we briefly examined available information regarding population status and extinction risk. Three other sockeye salmon stocks (Cedar River, Issaquah Creek, and Lake Washington beach spawners) are apparently introduced from outside the Lake Washington drainage and have not been included in a recognized ESU at this time (see above "Discussion and conclusions on ESU Determinations" section).

Riverine-Spawning Sockeye Salmon

Beyond WDFW Salmon Spawning Ground Survey Data (Egan 1977, 1995, 1997) and anecdotal reports (see above section "Information Specific to Sockeye Salmon Populations Under Review") of small numbers of sockeye salmon observed regularly spawning in some Puget Sound and coastal Washington rivers with no access to lake rearing habitat, we have no information on overall abundance or trends for these stocks.

Deschutes River, Oregon

Counts of sockeye salmon adults reaching Pelton Dam on the Deschutes River have been made during most years since the mid-1950s (Fig. 21). The most recent (1990-1994) 5-year average annual escapement was only 9 adults (see Appendix Table E-1). No accurate estimates of historical abundance are available for this unit, but a substantial run is known to have spawned in Suttle Lake prior to construction of a dam in the 1930s, and is believed to have continued to spawn in the Metolius River after that time (CBFWA 1990, Olsen et al. 1994, ODFW 1995a). Since construction of Pelton Dam, abundance has reached peaks of about 300 fish in several years (1962, 1963, 1973, 1976-Fish Commission of Oregon 1967, O'Connor et al. 1993). We have made no evaluation of abundance of kokanee in the Deschutes River basin, which may be part of the same evolutionary unit as sockeye salmon in this basin. Sockeye salmon derived from the GCFMP were introduced into Suttle Lake and the Metolius River between 1937 and 1961 (see "Artificial Propagation" section) (see Appendix Table D-3).

Sockeye salmon stock abundance has fluctuated considerably over time (recent escapements ranging from a low of 1 in 1993 to 340 in 1963), but there has been a substantial decline over the years for which data are available. For the full data series (1957-1994), abundance decreased by an average of about 3% per year; for the 1985-1994 period, abundance declined by about 13% per year. Nehlsen et al. (1991) identified Deschutes River sockeye salmon as at high risk of extinction.

Conclusions: Risk Assessment

The BRT has concluded that if recent conditions continue into the future, one ESU (Ozette Lake) is likely to become endangered, and four ESUs (Okanogan River, Lake Wenatchee, Quinault Lake, and Baker River) and one provisional ESU (Big Bear Creek) are not presently in significant danger of becoming extinct or endangered. For the sixth ESU (Lake Pleasant), there was insufficient information to reach a conclusion regarding risk of extinction.

Conclusions: Risk Assessment

Consideration was also given to the status of two other population units for which ESU status has not been determined. For one of these (riverine sockeye salmon) there was insufficient information to reach any conclusions regarding risk of extinction. For the other unit (Deschutes River sockeye salmon), the BRT concluded that the anadromous component is clearly in danger of extinction if not already extinct.

The following paragraphs summarize the conclusions for each ESU or other population unit, and major considerations leading to these conclusions are summarized in Tables 5 and 6.

These conclusions are tempered by uncertainties in specific critical information. For several units, there are kokanee (either native or introduced) populations using the same water bodies as sockeye salmon; potential interbreeding and ecological interactions could affect population dynamics and (in the case of non-native kokanee) genetic integrity of the sockeye salmon populations. With few exceptions, adult abundance data do not represent direct counts of adults destined to a single spawning area, so estimates of total population abundance and trends in abundance must be interpreted with some caution.

ESUs

ESU 1) Okanogan River

The BRT had several concerns about the overall health of this ESU. Low abundance, downward trends and wide fluctuations in abundance, land use practices, and variable ocean productivity were perceived as resulting in low to moderate or increasing risk for the ESU. Other major concerns regarding health of this ESU were restriction and channelization of spawning habitat in Canada, hydrosystem impediments to migration, and water temperature problems in the lower Okanogan River. Positive indicators for the ESU were escapement above 10,000, which is probably a substantial fraction of historical abundance, and the limited amount of recent hatchery production within the ESU. Recent changes in hydrosystem management (increases in flow and spill in the mainstem Columbia River) and harvest management (restrictions in commercial harvest to protect Snake River sockeye salmon) were regarded as beneficial to the status of this ESU. The BRT concluded unanimously that the Okanogan River sockeye salmon ESU is not presently in danger of extinction, nor is it likely to become endangered in the foreseeable future. However, the very low returns in the 3 most recent years suggest that the status of this ESU bears close monitoring and its status should be reconsidered if abundance remains low.

ESU 2) Lake Wenatchee

The BRT had several concerns about the overall health of this ESU. Low abundance, downward trends and wide fluctuations in abundance, and variable ocean productivity were perceived as resulting in low to moderate risk for the ESU. Other major concerns regarding the health of this ESU were the effects of hatchery production, hydrosystem impediments to migration, and potential interbreeding with nonnative kokanee on genetic integrity of the unit. Positive indicators for the ESU were escapement above 10,000, and the limited amount of recent hatchery production within the ESU. Recent changes in hydrosystem management (increases in flow and spill in the mainstem Columbia River) and harvest management (restrictions in commercial harvest to protect Snake River sockeye salmon) were regarded as beneficial to the status of this ESU. The majority of the BRT concluded that the Lake Wenatchee sockeye salmon ESU is not presently in danger of extinction, nor is it likely to become endangered in the foreseeable future. A minority concluded that this ESU is likely to become endangered in the foreseeable future, largely on the basis of extremely low abundance in the last 3 years. In any case, the very low returns in the 3 most recent years suggest that the status of this ESU bears close monitoring and should be reconsidered if abundance remains low.


ESU 3) Quinault Lake

All risk factors were perceived as very low or low for this ESU. However, the BRT had two concerns about the overall health of this ESU. The ESU is presently near the lower end of its historical abundance range, a fact that may be largely attributed to severe habitat degradation in the upper river, which contributes to poor spawning habitat quality and possible impacts on juvenile rearing habitat in Quinault Lake. The influence of hatchery production on genetic integrity is also a potential concern for the ESU. On the positive side, the BRT noted that recent escapement averaged above 30,000, harvest management has been responsive to stock status, and recent restrictions in logging to protect terrestrial species should have a beneficial effect on habitat conditions. The BRT concluded unanimously that the Quinault Lake sockeye salmon ESU is not presently in danger of extinction, nor is it likely to become endangered in the foreseeable future.

ESU 4) Ozette Lake

Perceived risks ranged from low to moderate for genetic integrity and variable ocean productivity, from low to moderate and increasing for downward trends and population fluctuations, and from moderate to increasing for abundance considerations. Current escapements averaging below 1,000 adults per year imply a moderate degree of risk from small-population genetic and demographic variability, with little room for further declines before abundances would be critically low. Other concerns include siltation of beach spawning habitat, very low abundance compared to harvest in the 1950s, and potential genetic effects of present hatchery production and past interbreeding with genetically dissimilar kokanee. The BRT concluded that the Ozette Lake sockeye salmon ESU is not presently in danger of extinction, but if present conditions continue into the future, it is likely to become so in the foreseeable future.

ESU 5) Baker River

The BRT had several concerns about the overall health of this ESU, focusing on high fluctuations in abundance, lack of natural spawning habitat, and the vulnerability of spawning beaches to water quality problems. Large fluctuations in abundance were a substantial concern. It is also likely that this stock would go extinct if present human intervention were halted, and problems related to that intervention pose some risk to the population. In particular, the BRT concluded that the proposed change in management to concentrate spawning in a single spawning beach could substantially increase risk to the population. There was considerable disagreement regarding the risks associated with several factors for this ESU. For example, the assessment of perceived risk for abundance and habitat capacity ranged among BRT members from very low to high, and classifications for risks related to water quality and disease also had wide ranges. The majority of the BRT concluded that the Baker sockeye salmon ESU is not presently in danger of extinction, nor is it likely to become endangered in the foreseeable future if present conditions continue. A minority concluded that this ESU is likely to become endangered in the foreseeable future, largely on the basis of lack of natural spawning habitat and the vulnerability of the entire population to problems in artificial habitats.

ESU 6) Lake Pleasant

Although escapement monitoring data are sparse, escapements (represented by peak spawner counts) in the late 1980s, and 1990s appear roughly comparable to habitat capacity for this small lake (peak spawner counts for the 1990s were not available at the time the BRT met). Some concerns were expressed regarding potential urbanization of habitat and effects of sport harvest during the migration delay in the Sol Duc River. It was noted that recent restrictions in logging to protect terrestrial species should have a beneficial effect on habitat conditions, although little or no old growth forest is present in the watershed. The majority of the BRT concluded that there was insufficient information to adequately assess extinction risk for the Lake Pleasant ESU, although a minority concluded that the ESU is not presently in danger of extinction nor likely to become so in the foreseeable future.

Provisional ESU

Big Bear Creek

The BRT had several concerns about the health of this provisional ESU and felt that the extreme fluctuations in recent abundances and potential effects of urbanization in the watershed suggest that the status of this populations bears close monitoring. Recent average abundance has been relatively high, with escapement between 10,000 and 20,000. Recent development of a county growth management plan was seen as a possible benefit to freshwater habitat for this population. The majority of the BRT concluded that the Big Bear Creek sockeye salmon provisional ESU is not presently in danger of extinction, nor is it likely to become endangered in the foreseeable future if present conditions continue. A minority concluded that this provisional ESU is likely to become endangered in the foreseeable future, while a second minority felt that information was insufficient to adequately assess extinction risk.

Other Population Units

Riverine-spawning sockeye salmon

There was insufficient information to reach any conclusion regarding the status of this unit.

Deschutes River, Oregon

The BRT concluded that if anadromous sockeye salmon recently seen in the lower Deschutes River are remnants of the historic Deschutes River ESU, the ESU clearly is in danger of extinction due to extremely low population abundance. If there is an ESU that includes sockeye salmon and native kokanee above Round Butte Dam, further evaluation of the kokanee stock and its relationship to the sockeye salmon would need to be completed before any conclusions regarding extinction risk could be made. If these sockeye salmon originated from stocks outside the Deschutes River Basin, then they are not subject to protection under the ESA.



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