Abstract
The use of marine reserves (an individual spatial closure in which no removal of organisms is allowed) to help sustain fisheries is today a fast-growing trend in fishery management worldwide. The optimum configuration of reserves based on their size, number, and distribution is still very uncertain. Advanced techniques from the fields of spatial modeling, operations research, and fisheries management are integrated to determine critical factors in the design of effective marine reserve plans for providing sustainable reef fish stocks. A methodology for extracting the average length in the exploitable phase of a stock from visual survey data is developed and used to conduct a retrospective assessment of the snapper, grouper, and grunt fish stocks in the Florida Keys National Marine Sanctuary. Over 60% of the stocks are 'overfished' and in need of management intervention, prompting further exploration into the use of marine reserves.A temporally and spatially explicit population simulation model (STOCaST) is developed to explore the effects of spatial variation in fishing effort and population distributions. Spatial estimates of population density and length distributions are determined for three species of reef fish to use as input to the model. Alternate reserve plans are designed using advanced techniques from the operations research field to produce plans of desirable shape and population characteristics. Four experiments are designed using these alternate plans to explore the impacts of numbers, sizes, and population content of marine reserve configurations for providing sustainable reef fisheries.A range of movement scenarios are simulated, and it is found that the sizes and numbers of reserves in a plan are only indirectly significant in reserve effectiveness. Results show that well-designed marine reserves can be used for species exhibiting a wide range of movement strategies to increase their spawning stock, abundance, and egg production, while minimizing yield losses to the fishery. However, the actual implementation of reserves is not a trivial matter, and if done haphazardly, may provide little or no benefit to the intended stocks, and may in some cases actually harm them. The proper design, implementation, and monitoring of reserves requires improved knowledge of the spatial distribution of both the intended stock and the fishing effort, as well as how and where the species move.