Reef fishes recruited at midwater coral nurseries consume biofouling and reduce cleaning time in Seychelles, Indian Ocean

Nursery-associated fish assemblages and behaviour were video-recorded prior to harvesting corals after a 20-month growth period and seven months post-coral harvesting. The density (ind. m–2) of blue-yellow damselfish Pomacentrus caeruleus was 12–16 times higher when corals were present than when corals were absent at the nurseries. Fish assemblages recruited into the nurseries included three trophic levels, from herbivores to omnivores, in six families: Ephippidae, Pomacentridae, Labridae (Scarinae), Gobiidae, Siganidae and Monacanthidae.

Higher abundance of large fish (total number of individuals) resulted in 2.75 times less person-hours spent in nursery cleaning. These results have important implications for cost-effective coral reef restoration.