Natural cleaning of the black-lip pearl oyster Pinctada margaritifera by butterflyfishes (Chaetodon) in French Polynesia
Résumé
Biofouling increases the operational and economic costs associated with pearl production. As current
procedures for reducing oyster biofouling can be detrimental to survival and growth and may pollute the
surrounding environment developing alternative, biologically-mediated, methods could potentially in-
crease both production and ecological sustainability. With this in mind, the present study investigated
natural cleaning of black-lipped pearl oysters, Pinctada margaritifera, by butterflyfishes (Chaetodon). The
feeding behaviour of six butterflyfish species was examined at Rangiroa Atoll, French Polynesia: Chae-
todon auriga, Chaetodon citrinellus, Chaetodon ephippium, Chaetodon lunulatus, Chaetodon trifascialis and
Chaetodon ulietensis. All species cleaned the surface of pearl oysters by removing epibionts (from 16% to
40% of total biomass), although dietary variation may explain different cleaning efficiencies. Generalist
omnivores (C. auriga, C. citrinellus, C. ephippium and C. ulietensis) were the most efficient cleaners (%
cleaning range: 26e40% of total biomass). Within this group, C. ephippium removed the most biomass
(average of 41%) targeting algae and anemones. However, C. auriga targeted the most diverse range of
epibionts, removing significant amounts of algae, sponges, tunicates, and anemones. These results
suggest that foraging by butterflyfishes can substantially reduce biofouling on economically-important
tropical bivalves.