Linking ecological and social elements to sustain coral reef fisheries : a case of groupers [Epinephelidae] in Mafia Island, Tanzania

The study of the dynamic nature of interactions within and between social and ecological aspects of reef fisheries is increasing, in order to promote understanding and to mitigate complex changes from global pressure and local threats that undermine sustainable coastal fisheries. In Tanzania, a trial fisheries policy allowing the export of grouper/rock cod, among other fishes, was endorsed in the year 2002. The policy goals were to improve the livelihoods of coastal communities and increase fish product exports. However, studies of the sustainability of commercially targeted fish species in Tanzania are inadequate; no information is available on the ecology and biology of groupers in Tanzanian marine waters that would ensure the sustainability of the fishery. There is a paucity of empirical evidence on impacts of management practices on ecological and social aspects of grouper fisheries. In particular, there is little documentation on the perceptions of small-scale fishers of changes related to Marine Protected Areas (MPAs) as a fisheries management tool. This study investigates linkages between ecology and social elements for sustainability of targeted finfish Epinephelinae (groupers) fisheries in Mafia Island, Tanzania. In particular, this study draws on insights from different knowledge sources to investigate ecological trends of groupers in a Marine Protected Area (MPA), and the biological traits of frequently caught grouper species. The aim is to gain scientific evidence to support sustainable grouper harvesting. Groupers are ecologically important as top-level predators and play a major role in structuring coral reef ecosystems. Being highly priced fish, groupers are heavily exploited for commercial purposes and for local consumption worldwide, hence they are susceptible to overfishing. This vulnerability to overfishing is exacerbated by the life history characteristics of groupers, such as longevity, late maturation and spawning aggregation behaviour.