Advantages and Disadvantages of Rotating Spatial Closures for Managing Fisheries

Abstract

Marine reserves are becoming an increasingly important tool in fisheries management. Particularly for species with relatively sedentary adults, the basic approach taken is to permanently close areas to fishing which allows species to recover inside the reserve and export larvae outside the reserve which eventually can be harvested. Two key issues are insuring the movement of larvae outside the reserve to support fisheries and the sociological and economic impact of permanent closures. An alternative approach that deals with these issues is rotating spatial closures which have been implemented for some fisheries. What has been missing is a general analysis of the relative impact of permanent closures versus rotating closures on fisheries yield that could be used to provide general principles to guide management. Using a simplified model with clear assumptions, we show that the approach that provides a higher yield depends on both dispersal and the fraction of the coastline in marine reserves. With high larval retention and small rotational fraction rotating closures are superior and the optimal rate of rotation cannot be too slow or too fast. These results provide quantitative guidelines in cases where decisions must be made in the face of limited data as well as providing a framework for more detailed analyses in cases where more data is available.