Terms of Reference

Assessment of Escapement Goals for Alsek River Chinook and Sockeye and Taku River Chinook and Coho

Pacific Regional Advisory Process

October 18-19, 2010
Nanaimo, British Columbia

Chairperson: Michael Chamberlain

Context

This Regional Advisory Meeting (RAP) will review four scientific assessments prepared to identify stock status and escapement goals for Coho and Chinook Salmon in the Taku River and Chinook and Sockeye Salmon in the Alsek River.  The overall objectives of the four papers are to describe the current status of the four stocks and to provide advice related to the appropriate biologically based escapement goals.  Information and advice presented in these documents and through the RAP proceedings will be used to support the management of these four salmon stocks through agreements outlined in the Transboundary chapter (Annex IX) of the Pacific Salmon Treaty.  

The following provides a general overview of the two working papers and two published papers that are to be reviewed.  

Towards a Coho escapement goal for the Canadian portion of the Taku River

The objective of this working paper is to determine the stock status of and provide biological based escapement goals for Taku River Coho salmon.  The revised Transboundary chapter of Annex IV of the PST requires the Parties to establish a bilaterally agreed MSY escapement goal for Taku River coho salmon in time for implementation in 2010.  The recommendations from this research document will be used by the management entities of the Parties to develop a revised integrated management plan for Taku coho salmon and may potentially affect calculations of TAC which could change harvest levels of the Parties.  The analyses will involve incorporation of mark-recapture, smolt, stock-recruitment and catch data.

Optimal Production of Chinook Salmon from the Taku River through the 2001 Year Class

The purpose of this analysis is to determine a biological escapement goal for the population of Chinook salmon from the Taku River based on the best available information. Ten years of stock assessment information have been added since the previous analysis was done.  A biological escapement goal range will be used to provide benchmarks for management of this Population.  Overview of the stock assessment programs used to gain knowledge of population dynamics since 1973 is provided. Sources of information are cited and analyses described. Adjustments to annual estimates from stock assessment programs are described in appendices to focus attention on links between spawning abundance and subsequent production of smolts and adults. 

This paper has been reviewed by both the Alaska Department of Fish and Game and the PST Chinook Technical Committee and published as an Alaska Department of Fish and Game Fishery Manuscript.

Optimum Escapement Goals for Chinook Salmon in the Transboundary Alsek River

Escapement goal analyses for stocks of Chinook salmon in the transboundary Alsek River and in one of its tributaries, the Klukshu River, are described. Data and estimates for harvest, in-river run size, harvest rates, relative age composition, and escapements for calendar years 1976 through 2007 are provided. Bayesian statistical analysis was used to address measurement error in estimated escapements, missing information on stock-specific harvests, missing data on relative age composition of some harvests, measurement error in estimates of relative age composition, process error, the possibility of autocorrelation in that process error, and the lack of small escapements in the data.

This paper has been reviewed by both the Alaska Department of Fish and Game and the PST Chinook Technical Committee and published as an Alaska Department of Fish and Game Fishery Manuscript.  See Additional Information & Reference below.

Run Reconstruction and Escapement Goals for Alsek River Sockeye Salmon

Escapement goal analyses for stocks of sockeye salmon in the transboundary Alsek River and in one of its tributaries, the Klukshu River, are described.  Data and estimates for harvest, in-river run size, harvest rates, relative age composition, and escapements for calendar years 1976 through 2008 are provided.  Bayesian statistical analysis was used to address measurement error in estimated escapements, missing information on stock-specific harvests, missing data on relative age composition of some harvests, measurement error in estimates of relative age composition, process error, and the possibility of autocorrelation in that process error.

Objectives

The objectives of this review are to:

• Evaluate each paper to determine the appropriateness of the data and the methods used within the analysis;
• Identify and evaluate the sources of uncertainty and the assumptions used in analysis;
• Evaluate the conclusions and recommendations respecting proposed escapement goals, along with any other conclusions and recommendations in each paper; and, 
• Provide a synthesis of the working papers, conclusions and advice.  

Outputs

Participation

Additional Information & References

McPherson, S.A., E. L. Jones III, S. J. Fleischman, and I. M. Boyce. 2010. Optimal Production of Chinook Salmon from the Taku River Through the 2001 Year Class. Alaska Department of Fish and Game, Fishery Manuscript Series No. 10-03, Anchorage.

Participation