Evidence for greater reproductive output per unit area in areas protected from fishing

Marine protected areas are advocated as an essential management tool to ensure the sustainable use of marine resources by providing insurance against over-exploitation and through the provision of refuge for a large biomass of sexually mature adults. Using a unique fishing gear-restriction, voluntary management system as a large-scale experiment, we found that adult scallops (Pecten maximus) within areas protected from towed bottom-fishing gear had heavier adductor muscle tissue and gonads that were 19%-24% heavier than those of scallops in fished areas, while other body and age characteristics were similar in both areas. The scallops within the protected area also occurred at a much higher abundance than adjacent, chronically fished (x 12.83) and wider commercially exploited (x 2.18) areas. These results provide evidence that the use of towed bottom-fishing gear can further exacerbate the effects of overfishing through the suppression of the reproductive potential of individuals of similar body size. These findings underline the utility of using closed areas as tools for fisheries conservation of sedentary species of commercial importance.