Evaluating large-scale experimental designs for management of coral trout on the Great Barrier

While biological information about targeted species is considered necessary for managing fisheries, alone it has proved insufficient to successfully manage both fisheries and ecosystems. Controlled experimental manipulations of fishing effort is likely to be the best mechanism for empirically assessing the responses of targeted stocks, other reef organisms, and fishing practices to changes in fishing pressure. Line fishing is a major extractive industry on the Great Barrier Reef of Australia, which is a mosaic of nearly 3000 separate reefs spread over 15 degrees of latitude and has high conservation value. Computer simulations of the population dynamics of the main target species, the common coral trout Plectropomus leopardus (Serranidae), based on recent field research were used to evaluate various designs for a large-scale experiment to examine aspects of the effects of line fishing in this region. The results indicated that large-scale experiments using whole coral reefs as units of experimental manipulation could be designed such that the field data collected would have good statistical power to detect impacts of fishing on target stocks and measure the responses of fished stocks to protection from further fishing. Such information on the line fishery is currently not available but will be critical to future decisions about management of this fishery and the Great Barrier Reef World Heritage Area.