Protection of East African reef fisheries

The Wildlife Conservation Society and partners report from Kenya:

Fishing is predicted to eliminate many of the ocean's fish stocks in the next few decades. To better manage fish and avoid the predicted fisheries collapse managers are frequently being asked to permanently close areas to fishing. These can be unpopular unless it is known whether or not closures will work and the amount of time that it takes for fish stocks to recover. Most investigations of closures are a single snapshot in time shortly after the closure and, although most investigations have found increases in fish, these studies produce few insights into the time it takes for fish to fully recover.

Tim McClanahan and colleagues were able to overcome this problem by studying four closures in Kenya's coral reef fisheries that were closed at different times in order to produce a nearly continuous recovery for over 37 years. They found that the numbers of species of fish increased up to 10 years after the closure and then remained unchanged, while the fishable stock reached its peak only after 25 years. Some species of fish did not, however, fully recover even after 37 years without fishing. Their findings suggest that recovery from fishing can be quite slow and that permanent closures may be the only way to insure that there are some areas representative of an unexploited ocean and to maintain fisheries stocks.

Towards Pristine Biomass: Reef Fish Recovery in Coral Reef Marine Protected Areas in Kenya is published in Ecological Applications Vol 17 No. 4, June 2007. For more papers by Tim McClanahan see here.