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IV. Biological Information Biological information regarding Snake River sockeye salmon is summarized in Attachment 1. Additional information can be found in NMFS (1995a). Escapement of Snake River sockeye salmon to the Snake River has declined dramatically in recent years. Counts made at Lower Granite Dam since 1975 have ranged from 531 in 1976 to zero in 1990. In 1988, IDFG conducted spawning ground surveys that identified four adults and two redds (gravel nests in which the eggs are deposited). In 1989, one adult reached Redfish Lake and one redd and a second potential redd were identified. No redds or adults were identified in 1990. In 1991, three males and one female returned to Redfish Lake. One male Snake River sockeye salmon returned to Redfish Lake in 1992. Six male and two female sockeye returned to Redfish Lake in 1993 and one female in 1994. No sockeye returned to Redfish lake in 1995. The estimated return of Snake River sockeye salmon to the Columbia River in 1996 is nine fish (TAC 1996). B. Snake River Spring/Summer Chinook Salmon Biological information regarding Snake River spring/summer chinook salmon is summarized in Attachment 1. Additional information can be found in NMFS (1995a). Although Snake River spring and summer chinook stocks have been listed as a single "distinct population segment," based on NMFS' finding that they constitute a single "Evolutionarily Significant Unit (ESU)" (Matthews and Waples 1991), Columbia River spring and summer chinook stocks are treated separately in management-related data bases. Spring and summer chinook are managed duringdifferent seasonal fishing periods using different regulatory criteria. The timing distinctions are, therefore, relevant to the understanding of the current management regime and the assessment of impacts. The return of upriver spring chinook in 1994 was a record low 21,075 including only 2,125 natural-origin spring chinook from the Snake River. The 1995 return of upriver spring chinook was 10,195 including 1,852 listed spring chinook. The anticipate return of upriver spring chinook in 1996 is 37,200 adults which includes 4,600 natural-origin fish from the Snake River (TAC 1996). The return of upriver summer chinook in 1994 was 17,695 including a record low 411 listed fish from the Snake River. The return of upriver summer chinook fish in 1995 was 15,044 including 534 natural-origin Snake River summer chinook. The forecast for 1996 calls for an expected return of 16,800 upriver summer chinook including 1,700 natural-origin fish from the Snake River (TAC 1996). Comparative run size information for spring and summer chinook for earlier years is contained in the biological assessment of Columbia River winter, spring and summer season fisheries (TAC 1996). Specific forecasts for years beyond 1996 will be developed annually as the necessary information becomes available. However, qualitative information suggests that returns will be higher than the very low returns observed in 1994 and 1995 through 1998. Both the 1992 and 1993 brood years experienced good outmigration conditions. The jack returns from the 1992 brood in 1995 support expectations for a higher return. The 1992 brood would contribute to returns primarily in 1996 and 1997, and the 1993 brood to returns in 1997 and 1998. After 1998, returns will likely decline again, due to the very low escapements in 1994 and 1995. C. Snake River Fall Chinook Salmon Biological information regarding Snake River fall chinook salmon is summarized in Attachment 1. The Columbia River fall chinook run has five major components: Lower River Hatchery, Lower River Wild, Bonneville Pool Hatchery, Upriver Bright, and Mid-Columbia Bright. Fall chinook from the Snake River are part of the Upriver Bright stock complex. Adult Snake River fall chinook salmon enter the Columbia River in July and migrate into the Snake River from August through October. Fall chinook salmon natural spawning is primarily limited to the Snake River below Hells Canyon Dam, and the lower reaches of the Clearwater, Grand Ronde, Imnaha, Salmon, and Tucannon Rivers. Fall chinook salmon generally spawn fromOctober through November and fry emerge from March through April. Downstream migration generally begins within several weeks of emergence (Becker 1970, Allen and Meekin 1973) with juveniles rearing in backwaters and shallow water areas through mid-summer prior to smolting and migration. They will spend one to four years in the Pacific Ocean before beginning their spawning migration. Using the available CWT data, it is possible to estimate the ocean distribution and relative fishery impacts on Snake River fall chinook. Since naturally-spawned fall chinook have not been marked or tagged, CWT data from fingerling releases from the Lyons Ferry hatchery most closely represent the stock. An analysis of CWT recoveries indicates that the Lyons Ferry stock is widely distributed and subject to harvest in the Columbia River and marine fisheries from southern California to Alaska (PFMC 1995). The estimated return of naturally-spawned Snake River fall chinook to Lower Granite Dam averaged 328 from 1986-1992, reaching a low of 78 in 1990. The corresponding return to Lower Granite Dam from 1991 to 1994 was 318, 533, 742, and 406, respectively. The projected return of listed fish to Lower Granite Dam in 1995 was 208. A final estimate for 1995 is not yet available, but is expected to be substantially higher than the preseason estimate. A forecast for 1996 is also not yet available at this time. D. Sacramento River Winter-run Chinook Salmon Prior to construction of Shasta and Keswick Dams in 1945 and 1950, respectively, winter-run chinook were reported to spawn in the upper reaches of the Little Sacramento, McCloud, and lower Pit Rivers (Moyle et al. 1989). Specific data relative to the historic run sizes of winter-run chinook prior to 1967 are sparse and anecdotal. Numerous fishery researchers have cited Slater (1963) to indicate that the winter-run chinook population may have been fairly small and limited to the spring-fed areas of the McCloud River before the construction of Shasta Dam. However, recent California Department of Fish and Game (CDFG) research in California State Archives has cited several fisheries chronicles that indicate the winter-run chinook population may have been much larger than previously thought. According to these qualitative and anecdotal accounts, winter-run chinook reproduced in the McCloud, Pit and Little Sacramento Rivers and may have numbered over 200,000 (Rectenwald 1989). Completion of the Red Bluff Diversion Dam in 1966 enabled accurate estimates of all salmon runs to the upper Sacramento River based on fish counts at the fish ladders. These annual fish counts document the dramatic decline of the winter-run chinook population. The estimated number of winter-run chinookpassing the dam from 1967 to 1969 averaged 86,509. During 1990, 1991, 1992, 1993, 1994, and 1995, the spawning escapement of winter-run chinook past the dam was estimated at 441, 191, 1180, 341, 189 and 1361 adults, respectively. The first winter-run chinook upstream migrants appear in the Sacramento-San Joaquin Delta during the early winter months (Skinner 1972). On the upper Sacramento River, the first upstream migrants appear during December (Vogel and Marine 1991). The upstream migration of winter-run chinook typically peaks during the month of March, but may vary with river flow, water-year type, and operation of Red Bluff Diversion Dam. Keswick Dam completely blocks any further upstream migration, forcing adults to migrate to and hold in deep pools downstream, before initiating spawning activities. Since the construction of Shasta and Keswick Dam, winter-run chinook spawning has primarily occurred between Red Bluff Diversion Dam and Keswick Dam. The spawning period of winter-run chinook generally extends from mid-April to mid-August with peak activity occurring in June (Vogel and Marine 1991). Aerial survey of spawning redds have been conducted annually by the CDFG since 1987. These surveys have shown that the majority of winter-run chinook spawning in the upper Sacramento River has occurred between the upper Anderson Bridge at RM 284 and the Anderson-Cottonwood Irrigation District (ACID) dam at RM 298. However, significant numbers of winter-run chinook may also spawn below Red Bluff (RM 245) in some years. In 1988, for example, winter-run chinook redds were observed as far downstream as Woodson Bridge (RM 218). Winter-run chinook eggs hatch after an incubation period of about 40-60 days depending on ambient water temperatures. The pre-emergent fry remain in the redd and absorb the yolk stored in their yolk-sac as they grow into fry. This period of larval incubation lasts approximately 2 to 4 weeks depending on water temperatures. Emergence of the fry from the gravel begins during late June and continues through September. The fry seek out shallow, nearshore areas with slow current and good cover, and begin feeding on small terrestrial and aquatic insects and aquatic crustaceans. As they grow to 50 to 75 mm in length, the juvenile salmon move out into deeper, swifter water, but continue to use available cover to minimize the risk of predation and reduce energy expenditure. The emigration of juvenile winter-run chinook from the upper Sacramento River is highly dependent on streamflow conditions and water year type. Once fry have emerged, storm events may cause en masse emigration pulses. Thus, emigration past Red Bluff may begin as early as late July, generally peaks in September, and can continue until mid-March in drier years (Vogel and Marine 1991). Data combined from 1981-1992 trapping and seining effortsshow that winter-run chinook outmigrants occur between early July and early May from Keswick to Princeton (RM 302 to RM 158). Emigration monitoring of Glenn Colusa Irrigation District (GCID) at river mile 206 shows that juvenile winter-run chinook migrate past GCID as early as mid-July and may continue through April (HDR Engineering Inc., 1993). In the Sacramento-San Joaquin Delta, winter-run chinook outmigrants generally occur from September through May as evidenced from trawling, seining, and State and Federal water project fish salvage data (CDFG 1993). Low to moderate numbers of juvenile winter-run chinook may occur in the fall, or later in the spring depending on the water year type. Large winter-run chinook juveniles have been salvaged as late as June (1982, 1983, 1986) at the State fish facilities, as well as at the Federal fish facilities (1987) (CDFG 1993). Peak outmigration through the Delta typically occurs from late January through May (Stevens 1989, Perry 1992).
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