MIXED-STOCK VS. TERMINAL FISHERIES: A BIOECONOMIC MODEL

ABSTRACT. This paper develops a bioeconomic model of a fishery conducted on several stocks, a large stock capable of supporting a commercial fishery, and one or more smaller stocks which could be driven to extinction at harvest rates that the larger stock can sustain. The model permits a shifting of effort from a mixed-stock fishery to single-stock fisheries. Such a shift could save the weaker stocks from extinction, but the model highlights economic incentives to reject this option. This points to a fundamental conflict between the preservation of biodiversity and economic pressures to maximize profits. This fundamental conflict has in turn important consequences in current debates over the restructuring of major fisheries including those directed at Pacific salmon.