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Restoration is an emerging tool for coral reef conservation, yet despite small‐scale successes there are concerns about high costs and ecological setbacks. Integration between reef ecology and restoration could help address such concerns. A prime example is the use of grazing by herbivores to reduce coral nursery cleaning costs. However, the relation between herbivore communities and cleaning benefits remains unquantified. This study aimed to measure links between herbivorous fish communities, grazing intensity and coral nursery performance. Six reefs were selected in southern Kenya, equally divided across three levels of fisheries management (fished < reserve < no‐take). Fish surveys determined herbivorous fish biomass and composition, and remote underwater videos recorded grazing intensity on coral nurseries. Accumulated fouling and coral growth were measured at the end of the 4‐month study. Grazing intensity was sixfold lower and fouling density fourfold higher in the fished areas compared to protected zones. Higher fouling strongly correlated with lower coral growth: exponential growth constants in fished areas were respectively twice and three times as low compared to marine reserves and no‐take zones. Across study sites grazing was dominated by bristletooth tangs (Ctenochaetus spp.), except where these were outcompeted by territorial damselfish. Thus, better coral nursery performance in protected areas can be partially linked to higher grazing intensity, which in turn is determined by both fish biomass and local species composition. We recommend protecting herbivorous fish species and placing coral nurseries in areas with high biomass of key grazers to improve coral nursery performance and reduce maintenance costs. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]