Sonar Estimation of Chinook and Fall Chum Salmon Passage in the Yukon River Near Eagle, Alaska, 2015 PDF Download

Author: Jody D. Lozori
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 58

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Book Description
Adaptive resolution imaging sonar (ARIS) and split-beam sonar equipment were used to estimate Chinook salmon Oncorhynchus tshawytscha and fall chum salmon Oncorhynchus keta passage in the Yukon River near Eagle, Alaska from June 30 to October 6, 2015. A total of 84,015 Chinook salmon were estimated to have passed the sonar site between June 30 and August 15. The midpoint of the Chinook salmon run occurred on July 23, which was 2 days early relative to the historical mean date of July 25. An estimated 112,095 fall chum salmon passed between August 16 and October 6. The sonar-estimated passage of fall chum salmon was subsequently expanded to a total passage estimate of 125,095 to include fish that may have passed after operations ceased. The midpoint of the expanded fall chum salmon estimate occurred on September 25, which is 3 days later than the historical mean date. Subtracting the preliminary subsistence catch upstream of the sonar site resulted in an estimated border passage of 83,674 Chinook salmon and 112,555 fall chum salmon. Drift gillnetting was conducted to collect age, sex, and length samples and tissue samples for genetic information. Species composition was also recorded to determine when the Chinook salmon run ended and the fall chum salmon run began.