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- Title
Escapement goal analysis and stock reconstruction of sockeye salmon populations (Oncorhynchus nerka) using life-history models.
- Authors
Lessard, Robert B.; Hilborn, Ray; Chasco, Brandon E.
- Abstract
We compare life-history models with the Beverton–Holt approach of escapement goal analysis. We model the life history of a sockeye salmon (Onchorhynchus nerka) population from a spawning stage, through juvenile and adult stages, and ending with adults that return to spawn. We fit models to data by statistically comparing predicted and observed numbers of four dominant adult ages. Posterior estimates of parameters from Markov chain Monte Carlo simulations are then used to assess optimal harvest policies. We search for policies that produce the highest average yield. We find that it is possible to detect density dependence with a life-history model where analysis of Beverton–Holt stock–recruitment relationship fails to do so. We find that Beverton–Holt relationships produce policies and long-term yield estimates that are inconsistent with empirical trends. Conversely, we find that optimal spawning stock sizes and maximum sustained yield estimates using the life-history model estimate are consistent with the historical behavior of fisheries examined. Adding smolt data to the analysis does not substantially change predicted optimal spawning stock size, but decreases the variance in estimated posterior parameter distributions and policy variable distributions.
- Subjects
SOCKEYE salmon; ONCORHYNCHUS; SPAWNING; SALMON; MONTE Carlo method; FISHERIES; AQUATIC resources; ANIMAL populations; SOCKEYE salmon fisheries
- Publication
Canadian Journal of Fisheries & Aquatic Sciences, 2008, Vol 65, Issue 10, p2269
- ISSN
0706-652X
- Publication type
Article
- DOI
10.1139/F08-130