Author : Sara E. Miller
Publisher :
ISBN 13 :
Total Pages : 61 pages
Book Rating : 4.:/5 (112 download)
Book Synopsis Chilkat Lake Sockeye Salmon Escapement Goal Review by : Sara E. Miller
Download or read book Chilkat Lake Sockeye Salmon Escapement Goal Review written by Sara E. Miller and published by . This book was released on 2018 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: We reviewed the escapement goal for the Chilkat Lake sockeye salmon (Oncorhynchus nerka) run, which is intensely harvested in the District 15 commercial drift gillnet fishery in Lynn Canal, Southeast Alaska. The current biological escapement goal of 70,000 to 150,000 sockeye salmon was established in 2009, based on a spawner-recruit analysis with weir counts converted to mark-recapture units. We fit age-structured state-space spawner-recruit models to updated 1976-2016 data on abundance, harvest, age composition, and coefficients of variation to examine the effect of autocorrelation and fry plants on recruits and to recommend a new biological escapement goal in Dual-frequency Identification Sonar (DIDSON) units. Historical mark-recapture and weir counts were considered indices of escapement, while the DIDSON counts (2008-2016) were considered 'true' counts of escapement. Fishery management reference points as well as optimal yield, optimal recruitment, and overfishing profiles were estimated from the final state-space Ricker model. Estimates derived from the state-space Ricker model suggest that the probability of achieving yields greater than 90% of maximum sustained yield from escapements at the current upper and lower bounds is 62% and 34%, respectively, and an average 65% over the entire escapement goal range. Therefore, we recommend maintaining the current biological escapement goal of 70,000 to 150,000 sockeye salmon counted at the Chilkat Lake weir site with the DIDSON sonar.