Coral Reef Benthos and Fisheries in Tanzania Before and After the 1998 Bleaching and Mortality Event

Research Group: Institute of Marine Sciences, University of Dar es Salaam, P.O. Box 668 Zanzibar; Tanzania

Surveys conducted in the 1980s and early 1990s indicated that coral reefs in Tanzania were being degraded by overexploitation and destructive resource harvesting practices, particularly dynamite fishing and the use of dragnets, with concomitant reduction in fish abundance. Despite reduction in dynamite fishing on most parts of the Tanzania coast, recent coral reef surveys (1999 and 2000) have indicated that live coral cover and the health of reef corals were further degraded by the 1998 coral bleaching event. The extent of coral mortality differed between areas and species. Although the relative contribution of some taxa such as acroporids and pocilloporids decreased on most reefs surveyed, there was no evidence of species extinction. Despite extensive coral mortality, there has been little evidence to suggest decline of reef fish abundance of commercial and artisanal fish catches. In many areas the dead reef structure has remained largely intact three years following the bleaching event. Coral recovery through growth of the surviving colonies and new coral settlement has been observed in all sites, but at different levels. The surviving Montipora, Echinopora and some Fungia were recovering faster than others in some sites. Studies in Mafia, Bagamoyo, Dar es Salaam and Tanga showed that pocilloporids had the highest number of recruits. Faster recovery will, however, depend on the level of natural and human disturbances in the near future. Appropriate reef management strategies, such as enforcement of existing regulations and establishment of more marine protected areas would help to prevent further coral reef degradation. Initiation of coral reef restoration programmes may also enhance the recovery process. Capacity building for coral monitoring/research and appropriate infrastructural support for coral reef ecosystem conservation would also bring noticeable improvement.

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