Re-Evaluating Stock Recruitment Relationship for Atlantic Salmon in Quebec

Since the early 2000s, management of Atlantic salmon in the Québec province has been based on biological reference points obtained from individual stock-recruitment relationships. Models were built using a frequentist approach and using abundance data from six index rivers between 1972 and 1990. A single density dependence relationship was then developed for each river and conservation limits were defined as Sopt75%: the number of spawners necessary for an optimal sustainable exploitation, with 75% probability. In this study, we incorporate 6 additional index rivers from Québec as well as an additional 15 cohorts. Using these 12 index rivers with dataset covering the 1972 to 2005 time period, a hierarchical Bayesian model was developed to obtain updated stock recruitment relationships. The new model also incorporate some environmental covariables which are related to the stock recruitment parameters. By doing so we are then able to estimate stock recruitment parameters for data-poor rivers across the province for which only environmental information is available.