Assessment Strategies for Data-limited Chinook Salmon Stocks of Western Alaska PDF Download

Author: Benjamin A. Staton
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 150

View

Book Description

Author: Benjamin A. Staton
Publisher:
ISBN:
Category : Fishery management
Languages : en
Pages : 231

View

Book Description

Author: Alaska. Division of Sport Fish
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 56

View

Book Description
Recent Alaska-wide downturns in productivity and abundance of Chinook salmon stocks have created social and economic hardships across many communities in rural and urban Alaska. There is a fundamental need to more precisely characterize productivity and abundance trends of Chinook salmon stocks across Alaska, gather essential information necessary to understand root causes of these widespread declines, and track population trends into the future. This document outlines a foundation of stock assessment and research programs among a suite of indicator stocks across Alaska designed as a long-term commitment to address fundamental knowledge gaps, elucidate causal mechanisms behind observed trends, and improve management capabilities. A team of nine Alaska Department of Fish and Game biologists and scientists worked collaboratively with federal agencies and academic partners to develop this plan to guide efforts towards better understanding productivity and abundance trends of Chinook salmon. In this plan we describe the general life history of Chinook salmon in Alaska; document stock-specific declines in productivity, abundance, and harvest that have occurred; and, described gaps in knowledge that limit management options when responding to downturns in productivity. The core of this proposed plan is a stock-specific, life history-based approach to research focused on twelve indicator stocks from around Alaska, representing diverse life history and migratory characteristics across a broad geographic range. Stock assessment programs on indicator stocks target specific objectives so that gaps in our knowledge of Chinook salmon can be addressed in a practical, cost-effective, and structured approach. The twelve indicator stocks, from Southeast Alaska to the Arctic-Yukon-Kuskokwim are: Unuk, Stikine, Taku, Chilkat, Copper, Susitna, Kenai, Karluk, Chignik, Nushagak, Kuskokwim, and Yukon rivers. Recommended stock assessments include enumeration of adult escapement and stock-specific harvests in all relevant fisheries, as well as estimates of juvenile Chinook salmon abundance during the smolt stage (Table 1 and Table 2). As a companion to these stock-specific and fishery-based projects, we also recommend a suite of local and traditional knowledge studies (Table 2), nearshore marine surveys, and life history process studies (Table 3). Approximate annual costs by type of activity are shown in Table 4. This plan represents a long-term effort where implementation of stock assessment programs on indicator stocks addresses critical knowledge gaps that limit management capabilities. Implementation to the fullest extent possible provides most opportunity for improved information to assist managers, particularly during times of low abundance.

Author: Kyle Shedd
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 0

View

Book Description
Chinook salmon originating in Alaska, British Columbia, and the Pacific Northwest are harvested in 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 (AABM) fisheries under provisions of the Pacific Salmon Treaty Agreement. The Alaska Department of Fish and Game has used genetic mixed stock analysis to estimate the stock composition of Chinook salmon harvests in the SEAK troll fisheries since 1998 and sport fisheries since 2004 based on a genetic baseline developed by the Genetic Analysis of Pacific Salmonids group for use in Pacific Salmon Treaty fisheries. Genetic methods allow direct estimation of the major stock groups contributing to these fisheries. This project estimated the relative stock composition of troll and sport fishery harvests from fishery accounting year (AY) 2019 (Oct. 1, 2018–Sept. 30, 2019). The major contributors to the troll and sport fisheries ordered from north to south were Southeast Alaska/Transboundary River, North/Central British Columbia, West Coast Vancouver Island, South Thompson, Washington Coast, Interior Columbia River summer/fall, and Oregon Coast reporting groups. Collectively, these 7 stock aggregates, referred to as driver stocks, accounted for 93% of the troll harvest and 95% of the sport harvest. The South Thompson driver stock was the largest contributor to the troll fishery (24% of the harvest), and Southeast Alaska/Transboundary River (TBR) and West Coast Vancouver Island stock groups were the largest contributors to the sport fishery (31% of the harvest each). Results indicate considerable temporal and spatial variation in the composition of troll and sport harvests in AY 2019, and changes in the relative contributions of driver stocks across years. Stock composition data from this and other stock assessments are being used to provide fisheries information, including stock-specific run reconstructions and forecasting of run sizes to transboundary rivers, and separate harvest estimates of SEAK and TBR wild and hatchery salmon.

Author: Kathrine G. Howard
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 85

View

Book Description
Long-term monitoring of juvenile Chinook salmon Oncorhynchus tshawytscha is needed to identify recruitment and mortality processes, to understand early marine biology and ecology, and develop tools useful for fisheries management. A sampling program for Yukon River salmon was established in the northern Bering Sea in 2003 but annual sampling has been tenuous due to funding limitations. This project was designed to maintain the sampling program for Yukon River stocks, develop a genetic baseline to identify Yukon River stocks, and evaluate a lower cost survey alternative using a smaller vessel and trawl configuration. Results indicated that the genetic baseline can identify four groups of populations from Western Alaska, the two vessel/trawl configurations provided similar estimates of juvenile Chinook salmon abundance (within 20%); however, sea state limitations of the small vessel required an earlier survey timing (August rather than September). The change in survey timing contributed to differences in the spatial distribution and length of salmon caught during the 2 surveys. Surveys identified above average juvenile Chinook salmon abundance during 2014-2016 and above average juvenile abundance per spawner in 2014 and 2015. Both indicate an improvement to the recent poor production of Yukon River Chinook salmon, because juvenile abundance in the northern Bering Sea is known to be a leading indicator of adult returns for this stock. Sampling 2 different time periods provided additional insight into the early marine growth rates of juvenile Yukon River Chinook and other salmon species. Average Chinook salmon growth rate was 1.55 mm per day from marine entry to August, and 1.06 mm per day from August through September. This project represents a critical step to enable the long-term monitoring of juvenile Chinook salmon in Western Alaska and continued pursuit of factors that determine productivity and cohort strength of Yukon River Chinook salmon.

Author: Sara Ellen Gilk
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 48

View

Book Description
The Southeast Alaska (SEAK) troll fishery harvests Chinook salmon originating from Alaska, British Columbia, and the Pacific Northwest. Owing to its mixed stock nature, the overall SEAK Chinook salmon fishery is managed as 1 of 3 such fisheries under provisions of the Pacific Salmon Treaty (PST) Agreement. The Alaska Department of Fish and Game has used genetic mixed stock analysis to estimate the stock composition of Chinook salmon harvests in the SEAK commercial troll fishery since 2004 based on a genetic baseline developed by the Genetic Analysis of Pacific Salmonids group for use in PST fisheries. Genetic methods allow direct estimation of the major stock groups contributing to fisheries. This project estimated the relative stock composition of seasonal troll fishery harvests from fishery accounting year 2015 (Oct. 1, 2014 - Sept. 30, 2015). The major contributors to the Southeast Alaska troll fisheries from largest to smallest were the Interior Columbia River (Summer/Fall), Southeast Alaska/Transboundary River, North/Central British Columbia, Oregon Coast, South Thompson, Washington Coast, and West Vancouver reporting groups. Collectively, these 7 stock aggregates accounted for 91% of the harvest and are referred to as driver stocks. Results indicate considerable temporal and spatial variation in the composition of troll harvests in accounting year 2015, but consistent patterns of composition across years. Stock composition data from this and other stock assessments are being used to provide fisheries information, including stock-specific run reconstructions and 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, and estimating some terminal run sizes of stocks in the PST area that drive the SEAK fishery.

Author: Kyle Shedd
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 72

View

Book Description
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.

Author: Sara Ellen Gilk
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 79

View

Book Description
The Southeast Alaska (SEAK) troll fishery harvests Chinook salmon originating from Alaska, British Columbia, and the Pacific Northwest. Owing to its mixed stock nature, the overall SEAK Chinook salmon fishery is managed as one of 3 such fisheries under provisions of the Pacific Salmon Treaty (PST) Agreement. The Alaska Department of Fish and Game has used genetic mixed stock analysis to estimate the stock composition of Chinook salmon harvested in the SEAK troll fishery since 2004 based on a genetic baseline developed by the Genetic Analysis of Pacific Salmonids group for use in PST fisheries. Genetic methods allow direct estimation of the major stock groups contributing to fisheries. This project estimated the relative stock composition of seasonal troll fishery harvests from fishery accounting years 2010 to 2014 (Oct. 1, 2009-Sept. 30, 2014). The major contributors to the Southeast Alaska troll fisheries on an annual basis are the Andrew Creek, Southern Southeast Alaska, British Columbia Coast/ Haida Gwaii, West Coast Vancouver Island, Interior Columbia River (Summer/Fall), North Oregon Coast, Washington Coast, and South Thompson reporting groups. Results indicate considerable temporal and spatial variation in the composition of troll harvests within years, but consistent patterns of composition across years. Stock composition data from this and other stock assessments are being used to provide fisheries information including stock-specific run reconstructions and forecasting of transboundary river run sizes, determining the origin of catches in the SEAK troll fishery by age to assist in evaluation of the Pacific Salmon Commission Chinook Model, and estimating some terminal run sizes of some stocks in the PST area that drive the SEAK fishery.

Author: James William Savereide
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 244

View

Book Description
"Chinook salmon in Alaska support human uses through a variety of fisheries. Age-structured assessment models are rarely used for estimating the abundance of exploited stocks. This thesis develops a model for the Copper River chinook salmon population to show its advantages over typical assessment models. Information consists of catch-age data from three fisheries (commercial, recreational, subsistence), and two sources of auxiliary data (escapement index, spawner-recruit relationship). Four approaches utilizing different information sources are explored. Results suggest that an approach utilizing pooled catch-age data with time-varying brood-year proportions produces the best estimates, although retrospective and sensitivity analyses suggest that all four approaches explored are robust. The model should assist managers when making management decisions, because it integrates all sources of information, accounts for uncertainty, and provides estimates of optimal escapement. The model shows promise as a method for assessing and forecasting chinook salmon populations"--Leaf 3.

Author: Kyle Shedd
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 73

View

Book Description
Chinook salmon originating in Alaska, British Columbia, and the Pacific Northwest are harvested in 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 Agreement. The Alaska Department of Fish and Game has used genetic mixed stock analysis to estimate the stock composition of Chinook salmon harvests in the SEAK troll and sport fisheries since 2004 based on a genetic baseline developed by the Genetic Analysis of Pacific Salmonids group for use in Pacific Salmon Treaty fisheries. Genetic methods allow direct estimation of the major stock groups contributing to these fisheries. This project estimated the relative stock composition of troll and sport fishery harvests from fishery accounting year (AY) 2018 (Oct. 1, 2017–Sept. 30, 2018). The major contributors to the troll and sport fisheries ordered from north to south were the Southeast Alaska/Transboundary River, North/Central British Columbia, West Coast Vancouver Island, South Thompson, Washington Coast, Interior Columbia River Summer/Fall, and Oregon Coast reporting groups. Collectively, these 7 stock aggregates, referred to as driver stocks, accounted for 91% of the troll harvest and 95% of the sport harvest. The Southeast Alaska/Transboundary River driver stock was the largest contributor to both the troll (18%) and sport fishery (38%) harvest. Results indicate considerable temporal and spatial variation in the composition of troll and sport harvests in AY 2018, and changes in the relative contributions of driver stocks across years. Stock composition data from this and other stock assessments are being used to provide fisheries information including stock-specific run reconstructions and forecasting of run sizes to transboundary rivers, and separate harvest estimates of SEAK and transboundary river wild and hatchery salmon.