Nechako River White Sturgeon Recovery Planning

Résumé du livre

This is the report of a workshop that focussed on three questions: the evidence for a decline in the recruitment of juvenile white sturgeon (Acipenser transmontanus) in the Nechako River, British Columbia; the potential causes of this decline; and the experimental management regimes that could be used to resolve uncertainties on the cause of recruitment problems and thereby direct mitigation strategies. After an introduction on the proceedings, section 2 reviews the data used to evaluate recruitment trends. It includes a comparison of Nechako stock age composition with Fraser River stocks, an indication of historical changes in Nechako stock age composition, and interpretations of the decline in catch rates 1982-99. Section 3 presents a sturgeon population model used to make additional interpretations of recruitment trends, and evaluates predicted estimates of recruitment patterns over time, based on current age-structure data. Section 4 summarizes the workshop discussions focussed on identifying potential causes of the recruitment failure. The final section summarizes discussions on the design of an experimental management program intending to identify successful strategies for recovering the Nechako white sturgeon stock.