Economic Impacts of Changes in Fish Population Dynamics: The Role of the Fishermen's Harvesting Strategies

摘要

Using a bioeconomic model of the cod {Gadus morhua) and capelin (Mallotus villosus) fisheries of the Barents Sea, this study assesses the role of the fishermen's behavior in reducing or intensifying the effects on the stocks caused by altered population dynamics. The analysis focuses on the economic development of the fisheries employing a coupled stock size-hydrography-based fishing strategy, which attempts to maximize returns from fishing over a given number of fishing periods. Results show that if the fishing strategy is based on a short optimization period of only two fishing periods, changes in population dynamics have a direct influence on the returns from fishing due to the strong pressure on the stocks applied by the fisheries. If the strategy is based on a longer optimization period, fishing activities may be deferred to allow for stock regrowth, which improves the economic performance of the fisheries. However, in that case, the relationship between population dynamics and fishing activities becomes less clear, as even a reduction of the carrying capacities of the two species allows for an increase in the amount of fish landed without causing a stock collapse due to an increased efficiency of fleet utilization. The simulations indicate that management considerations and the time horizon of the fishing strategy dominate the influence of altered population dynamics on the development of the stocks considered in the model.