Previous research on reserve-based management, where protected areas are permanently closed to fishing, has suggested that fishery yield will increase through intensive fishing in the areas between the reserves. However, this strategy could end up being more costly because of the ‘stock effect’. The stock effect is where fishing becomes expensive to carry out because over-fishing has led to low-density populations which require increased efforts to harvest. Increased yields would not compensate for the greater costs of fishing in over-fished areas and profits would therefore be a better measure of economic performance than yields.
Even with the stock effect, the researchers suggest that the inclusion of marine reserves can increase fishery profit compared with that which can be attained using conventional management without reserves. Although the stock effect reduced fishery profit under both management strategies, reserve-based management could generate at least the same profits, if not more, as conventional management.
The researchers evaluated a range of fishery management options, each with different amounts of coastline set aside as reserves. Having small or moderate proportions of the coastline as reserves, for example 20 per cent, provided similar yields and profits across a range of reserve configurations and management styles. With larger proportions as reserves, maximum yields and profits were achieved when reserves were configured to be small to medium-sized with small or moderate distances between them. This approach enabled sufficient numbers of new fish produced in reserves to enter adjacent areas and be harvested by fisheries.
Previous studies focused on maximizing fishery yield have also suggested that along with intensive fishing reserves should constitute a large proportion of the coastline, for example 50 per cent. The economic perspective revealed by this study indicates that such a strategy usually reduces fishery profit. Instead, reserve-based management offers the most benefits to fisheries when harvest pressure is less intensive in conjunction with only a moderate proportion of the coast in reserves. Moreover, within a practical range, reserve areas could be traded off with harvest intensity with little impact on profits.
Management strategies using reserves should be flexible, and choose the best combinations of sizes and proportions of coastal reserves for specific areas. The uncertainties associated with fishery management and the concerns of industry and conservationists could also be incorporated in such policies, which would manage fisheries for long-term sustainability. Reserve-based management could also help meet the twin objectives of creating more employment whilst also ensuring the health of the European Union’s marine resources, as explained in the Integrated Maritime Policy.