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2019 Annual Report
出版Idaho Department of Fish and Game, 2020
URLhttp://books.google.com.hk/books?id=UevRzgEACAAJ&hl=&source=gbs_api
註釋[Chapter 1] This chapter summarizes the abundance and composition of wild steelhead and springsummer Chinook Salmon returning to Lower Granite Dam in spawn year 2019. We used a combination of window counts and systematic biological samples from the fish trap to decompose each species by origin, body size, sex, age, and stock. These metrics were then used to calculate adult-to-adult productivity, expressed as recruits per spawner for each species, and smolt-to-adult return rate for spring-summer Chinook Salmon. The combined window count was 51,818 hatchery and wild steelhead. The estimated wild steelhead escapement was 8,287 (90% CI 7,966-8,611) fish, which comprised 16% of the window count resulting in a decrease for the fourth consecutive year. With the exceptions of the South Fork Clearwater stock, the South Fork Salmon stock, and the Upper Salmon stock, point estimates for wild escapement declined for all genetic stocks in SY2019 for the fourth consecutive year. The Grande Ronde River genetic stock was the most abundant followed by the lower Snake River. Small steelhead (