Estimates of Sustainable Exploitation Rates for Columbia River Landlocked White Sturgeon: Evaluating the Importance of a Maximum Size Limit
Life history computer simulations, along with available parameter estimates, were used to evaluate sustainable exploitation rates for landlocked white sturgeon, Acipenser transmontanus, of the Columbia River. The results of the simulations show that the long life span and high fecundity of sturgeon mean that a relatively few mature fish (a few percent of the fishable population) may support the fishery. The results suggest that 35% annual exploitation rates for fish older than 12 years are not unrealistic under the current six-foot (189.9 cm) maximum legal size limit (6FSL). Without the 6FSL, sustainable exploitation rates varied between 9% and 25% depending on the assumed levels of gear size-selection for fish larger than 182.9 cm. Gear size-selection estimates suggest that these large fish have high catchability in comparison to smaller fish. The 6SFL is important in maintaining a commercially exploitable population.
Debort, A., H. Schaller, and M. Matylewich. 1989. Estimates of sustainable exploitation rates for Columbia River landlocked White Sturgeon: evaluating the importance of a maximum size limit. Columbia River Inter-Tribal Fish Commission Technical Report 88-4. 46p.