Fisheries, Subsistence, and Habitat
Publications Searchable Database
Search Again| Division: | Sport Fish |
| Title: | Escapement goals for Chinook salmon in the Blossom and Keta rivers |
| Author: | Fleischman, S. J., J. A. Der Hovanisian and S. A. McPherson |
| Year: | 2011 |
| Report ID: | Alaska Department of Fish and Game, Fishery Manuscript No. 11-05, Anchorage. |
| Abstract: | Production of adult Chinook salmon from the Blossom and Keta rivers was investigated using stock assessment information collected in 1975–2007. Estimates of inriver returns, relative age composition, and escapements are presented. Exploitation rates from the nearby Unuk River Chinook salmon stock were fit to a hierarchical model and used as proxies to estimate total returns. An age-structured Ricker spawner-recruit model was fitted to the data from both stocks, which allowed estimation of key population reference points and an informed choice of escapement goals. Bayesian statistical methods were employed to provide realistic assessment of uncertainty in the presence of measurement error, serial correlation, and missing data. Biological escapement goals of 150–300 and 175–400 large (=660 mm mideye to fork of tail) fish, as counted in helicopter surveys, are recommended for Chinook salmon spawning in the Blossom and Keta rivers, respectively. These goals minimize the danger of recruitment overfishing. Continuation of the annual escapement sampling and standardized peak survey count programs are recommended for both rivers. |
| Keywords: | Chinook salmon, Oncorhynchus tshawytscha, Keta River, Blossom River, spawning abundance, helicopter survey, expansion factor, age composition, spawner-recruit analysis, sustained yield, escapement goal, measurement error, serial correlation, missing data, Bayesian statistics, age-structured model, hierarchical model, WinBUGS. |