Chinook Salmon Fisheries And Harvests In Southeast Alaska

Author : Kyle Shedd
Publisher :
ISBN 13 :
Total Pages : 72 pages
Book Rating : 4.:/5 (123 download)

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Download or read book Mixed Stock Analysis of Chinook Salmon Harvested in Southeast Alaska Commercial Troll and Sport Fisheries, 2017 written by Kyle Shedd and published by . This book was released on 2021 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chinook salmon originating from Alaska, British Columbia, and the Pacific Northwest are harvested in the Southeast Alaska (SEAK) commercial troll and sport fisheries. Owing to its mixed stock nature, the overall SEAK Chinook salmon fishery is managed as 1 of 3 aggregate abundance-based management fisheries under provisions of the Pacific Salmon Treaty (PST) Agreement. Genetic methods have been implemented in SEAK since 2004 and allow direct estimation of the major stock groups contributing to these fisheries. This project estimated the relative stock composition of SEAK troll and sport fishery harvests from fishery accounting year (AY) 2017 (October 1, 2016-September 30, 2017). The major contributors to the SEAK fisheries ordered from north to south were the Southeast Alaska/Transboundary River, North/Central British Columbia, West Vancouver, South Thompson, Washington Coast, Interior Columbia River Summer/Fall (Su/F), and Oregon Coast reporting groups. Collectively, these 7 stock aggregates, referred to as driver stocks, accounted for 89% of the troll harvest and 95% of the sport harvest. The Interior Columbia River Su/F driver stock was the largest contributor to the troll fishery (24% of the harvest), and Southeast Alaska/Transboundary River was the largest contributor to the sport fishery (28% of the harvest). Results indicate considerable temporal and spatial variation in the composition of troll and sport harvests in AY 2017 and across years. Stock composition data from this and other stock assessments are used to provide fisheries information including stock-specific run reconstructions, forecasting of run sizes to transboundary rivers, determining the origin of catches in the SEAK troll fishery by age to assist in evaluation of the Pacific Salmon Commission Chinook Model, estimating harvest of SEAK and transboundary river wild and hatchery salmon separately, and estimating some terminal run sizes of stocks in the PST area that drive the SEAK fishery. three-event mark-recapture experiment was conducted on northern pike Esox lucius in Minto Flats, Alaska from March through August 2018. Abundance was estimated for 2 specific populations: 1) an overwintering population residing in the Chatanika River upriver from its confluence with Goldstream Creek, called the Chatanika River Overwintering Area (CROA); and 2) a summer population occupying a wetland complex defined as the Minto Lakes Study Area (MLSA). Fish were sampled and marked in the CROA from 7-23 March 2018 and 12-21 June 2018 in the MLSA. Recapture events occurred in the MLSA from 12-21 June 2018 (concurrent with marking) and 7-16 August 2018. One-hundred radio tags were deployed during March 2018 to evaluate movements of northern pike relative to the mark-recapture experiment. Two models were used to estimate abundances: a traditional two-event Petersen mark-recapture model for closed populations, and a multinomial Bayesian model. The Petersen model abundance estimate of fish ≥600 mm fork length (FL) in the CROA was 14,817 (SE = 1,836) and for the MLSA was 11,956 (SE = 5,836). The Bayesian multinomial model abundance estimate for fish ≥600 mm FL in the CROA was 14,675 (SE = 1,631) and for the MLSA was 11,443 (SE = 1,651). The Bayesian multinomial model generated more precise estimates because it used data from all sampling events and incorporated information from the radiotagged fish. There were significantly more northern pike in the MLSA than what was found in 2008. Biases in the estimates were addressed and the 2 modeling approaches were evaluated. The current exploitation rate of northern pike in Minto Flats is 7.3%, which is well below the maximum threshold stipulated by the joint sport and subsistence fishery management plans.