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Abundance, Distribution, and Migration Patterns of Summer Chum Salmon in the Yukon River Drainage, 2014-2015

Sean LarsonHolly C. CarrollJan Marie ConitzBonnie M. Borba

出版	Alaska Department of Fish and Game, Division of Sport Fish, Research and Technical Services, 2017
URL	http://books.google.com.hk/books?id=wCf0swEACAAJ&hl=&source=gbs_api

註釋Summer chum salmon (Oncorhynchus keta) in the Yukon River support robust commercial and subsistence fisheries; however, fishery managers have had incomplete information about their run timing, spawning distribution, stock composition, and abundance. To address this, a radiotelemetry study was implemented on summer chum salmon in 2014 and 2015. A total of 1,232 (2014) and 1,199 (2015) summer chum salmon were fitted with radio transmitters. Radiotagged summer chum salmon were mapped, travel rates were estimated, and proportions of tagged fish recovered within different tributaries were determined. Basic mark-recapture assumptions were tested and abundance above the tagging site was estimated. Summer chum salmon were found to be widely distributed within the Yukon River drainage. Although a few tagged fish were observed in most locations, roughly 50% of tagged fish were observed in the Anvik, Koyukuk, and Bonasila rivers each year. Summer chum salmon destined for upper river spawning areas traveled faster than those to lower river areas. Summer chum salmon tended to recover quickly after being tagged, and traveled relatively fast within the mainstem Yukon River, but slowed down after entering their spawning tributaries. The 2014 mark-recapture abundance estimate was about 2,100,000 fish, which corresponded with summer chum salmon passage at the mainstem Yukon River sonar near Pilot Station. The 2015 mark-recapture abundance estimate was also about 2,100,000 fish, which was larger than the summer chum salmon passage at the sonar near Pilot Station. Results from this study help to evaluate sonar passage estimates and provide fishery managers with more detailed information about distribution and migratory patterns of individual summer chum salmon stocks within the Yukon River drainagewide population.