Little Susitna River Chinook And Coho Salmon Escapement Studies 2012 2016

Author : Lisa Ann Stuby
Publisher :
ISBN 13 :
Total Pages : 64 pages
Book Rating : 4.:/5 (15 download)

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Download or read book Chinook Salmon Escapement in the Chena and Salcha Rivers and Coho Salmon Escapement in the Delta Clearwater River, 2016 written by Lisa Ann Stuby and published by . This book was released on 2018 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: During 2016 the Alaska Department of Fish and Game conducted salmon enumeration projects on the Chena, Salcha, and Delta Clearwater rivers in the Tanana River drainage. Chinook salmon Oncorhynchus tshawytscha escapements for the Chena and Salcha rivers were estimated using tower-counting techniques with the addition of sonar (DIDSON and ARIS) methodology as a secondary means of enumeration when high-water events precluded visual counts. A Bayesian mixture model was used to apportion species from the sonar files. Coho salmon Oncorhynchus kisutch escapement in the Delta Clearwater River was estimated by a visual boat survey at peak escapement. The counting towers operated on 26 June for the Chena River and 26 June-3 July and 11-17 July for the Salcha River until high, muddy water precluded visual counts. Sonars could not be operated due to flooding from 19 July-5 August for the Chena River and during 19-26 July and 31 July-5 August for the Salcha River. A Bayesian hierarchical model was used to estimate salmon abundance for days when the sonars were not operating. Estimated Chinook salmon escapement for the Chena River was 6,665 (SE = 363) and 2,675 (SE = 313) for the Salcha River. Due to flooding and sonar placement, the abundance estimate for the Salcha River represents a minimum. During the carcass surveys 388 and 503 Chinook salmon were collected from the Chena and Salcha rivers respectively to estimate the age, sex, and length composition of the escapement. Dominant age classes were age 1.2 (0.43) for males and age 1.3 (0.14) for females for the Chena River and 1.2 (0.37) for males and age 1.3 (0.17) for females for the Salcha River. Estimated proportion of females was 0.22 (SE = 0.02) and the proportion adjusted for gender-bias was 0.16 (SE = 0.03) for the Chena River and 0.38 (SE = 0.02) and gender-bias adjusted was 0.33 (SE = 0.07) for the Salcha River. Mean length of females in the Chena River escapement was 771 mm and 629 mm for males and the mean length of females in the Salcha River escapement was 746 mm and 631 mm for males. Chum salmon Oncorhynchus keta escapement for the Chena and Salcha rivers was 6,493 (SE = 427) and 2,897 (SE = 177), respectively. Because counting operations ceased during the chum run, these counts were considered incomplete. The peak escapement count of coho salmon escapement in the Delta Clearwater River on 26 October was 6,767.