Defended territories of an aggressive damselfish contain lower juvenile coral density than adjacent non-defended areas on Kenyan lagoon patch reefs
Jewel damselfish, Plectroglyphidodon lacrymatus, aggressively defend small territories on coral reefs in which they cultivate lawns of edible macroalgae. Pairwise frequency counts showed that juvenile coral density was lower inside damselfish territories than that in adjacent non-defended areas on lagoon patch reefs in Kenya. These differences in coral density decreased as coral size increased. Direct farming effects of the damselfish and indirect inhibitory effects from higher algal densities inside territories are both thought to be potentially responsible for the results attained herein. Damselfish territories can occupy a large proportion of a coral reef; territorial behaviour in fish may have greater impacts on reef structure, in particular the resilience and growth rate of juvenile corals, than previously appreciated.
KeywordsCoral density Coral reef resilience Damselfish Farming Juvenile coral Territoriality
We thank Professor William Sutherland for his helpful comments on previous drafts of the manuscript. We thank all who assisted in fieldwork, in particular Peter Musembi and Sofi Kosimbei of A Rocha Kenya. We thank the Kenya Wildlife Service for their cooperation during our work in the Watamu Marine National Park, and the Christ’s College Bursary Scheme, the Henry Martyn Trust, and the Timios Trust for helping to fund this work.
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