Investigators: Tim R McClanahan (WCS, Kenya), NVC Polunin, N. Graham, and S. Stead (UK), M. Stravens, J. Bijoux, R. Quatre, G. Rosine, and P. Andre Adam (Seychelles), Pascale Chabanet, S. Stead, L. Bigot, P. Durville, and M. Tessier (Reunion); J. Cinner (Australia), Joseph Maina and J. Kawaka (Kenya); A.T. Kamukuru, Saleh Yahya, Mohammed Nur Mohammed (Universty of Dar es Salaam), Haji Machano Ali (WWF), and Marcus Öhman (Stockholm University, Sweden)
MAP OF STUDY SITES
The project aimed at evaluating the effects of coral bleaching and mortality on the coral reef communities, fish, and fisheries in the western Indian Ocean through a combination of field studies before and after the coral bleaching event in 1998, and the development of a historical database on benthic and fish communities.
The project aimed to elucidate what happens to the coral reef fish assemblage in response to coral bleaching in the medium- to long-term (7-8 years) and thus derives implications for fisheries, tourism, and biodiversity conservation. The study achieved this by four methods; repeat detailed benthic and fish surveys at four locations across the Indian Ocean, continuation of a long-term fishery dependant survey of east African reefs, a meta-analysis at the scale of the western Indian Ocean and modelling of the three scenarios outlined above within the context of the western Indian Ocean.
Specifically, the project tested the following aims and hypotheses:
- The change in fish communities is greater on reefs with a history of bleaching and coral mortality than those without this history
- Loss of live coral through bleaching is associated with a reduction in the abundance of animals that are strict corallivores and specialists otherwise dependent on the live cover.
- Increased turf algal cover is associated with increases in herbivorous fish and other grazers on reefs, whereas fleshy algal dominance has an overall negative effect.
- Structural complexity of dead reefs is reduced post bleaching.
- Smaller prey fish species are more affected by a reduction in structural complexity than larger predatory species.
- If structural complexity has declined markedly, a reduction occurs in the density, diversity, and biomass of the associated fish assemblage, including those targeted by fisheries.
- Areas heavily affected by fishing are more affected by the bleaching event than those protected from fishing.
- Fisheries production is reduced on reefs heavily affected by bleaching.
- Implement socioeconomic monitoring at twelve coral reef study sites in the four countries that will form a baseline for regular socioeconomic monitoring at these sites.
- Integrate this socioeconomic data with existing and proposed ecological data on marine protected areas, gear, dive, and ornamental collection restrictions, and coral bleaching to inform and improve coral reef management in East Africa.
- Examine the longer-term socioeconomic effects from the 1998 coral bleaching event
- Use this information in conjunction with socioeconomic and ecological data to help understand and improve responses to coral bleaching in East Africa and the Western Indian Ocean.
- Use this information in conjunction with existing WCS ecological data and SocMon-based research in Indonesia and Papua New Guinea to conduct a highly detailed meta-analysis of how socioeconomic factors influence the use and management of coral reefs throughout the Indo-Pacific.
- To influence the plans and activities of marine resource managers in the region by informing them of the results of the various studies.
- To help maintain the system of dialogue and exchange of information between stakeholders and end-users in order to promote longer-term conservation, governance, management and policy goals for coral reef ecosystems.