Research and management of competing small-scale and industrial fisheries: a modeling study of the shrimp fisheries in Mozambique

Abstract

The shrimp fisheries in tropical areas often present interactions between the fleets that are taking part in the fishery: industrial fleet and small-scale sector. The fisheries in the Sofala bank, Mozambique, are an excellent case study of such interactions. In this study a simulation model is used to analyze different scenarios and management issues: lack of information in the fishery, catches of artisanal fleet not taken into account in stock assessments, same management measures applied to both fleets, over-crowded fishery, and interactions through catches and by-catches. Although coarse, the model appears to model appropriately some of the main characteristics of a two-fleet two-prey fishery without biological interactions. Six-management scenarios differing mostly on the extension and timing of closed seasons in the shrimp fishery were simulated, following earlier practices and recommendations from different authors. These scenarios suggest that for maximizing yield and profit in the long term a strong reduction in the trawler fleet would be most appropriate. With large fleets present, as in the late 2000’s, increased closed seasons may, or not, be beneficial for the stocks, but seem to be little economically efficient as they don’t deal with the race to fish.