The 1997/1998 mass mortality of corals: Effects on fish communities on a Tanzanian coral reef

The abnormally high surface temperatures in the world's oceans during 1997/ 1998 resulted in widespread coral bleaching and subsequent coral mortality. An experiment was performed to study the effects of this coral mortality a s well as the influence of the structural complexity on fish communities on a Tanzanian coral reef. Changes in fish communities were investigated on p lots of transplanted corals after 88% of these corals had died. A distinct shift in fish community composition was found, although diversity was not a ffected. Fish abundance rose by 39% mostly due to an increase in herbivores , which seemed to benefit from enhanced algal growth on the dead corals. Fi sh abundance, species diversity and community composition were also strongl y influenced by the structural complexity provided by the live and dead cor als. This suggests that a coral reef can support abundant and diverse fish populations also after the corals have died as long as the reef structure i s sustained. (C) 2001 Elsevier Science Ltd. All rights reserved.