Behavioral observations of an upcurrent reef colonization event by larval surgeonfish Ctenochaetus strigosus (Acanthuridae)

Abstract

Two reef colonization events by larval acanthurids were observed at Johnston Atoll, Central Pacific. In one event, pelagic larvae of Ctenochaetus strigosus were observed swimming in groups along the bottom of a reef channel and actively settling to caves and crevices. These larvae were swimming against a current that averaged 27 cm s-1 at a height of 1.5 m above the substrate. This observation confirms the importance of larval swimming abilities during colonization of some reef fishes and indicates a potential undersampling of larvae by passive plankton nets. Predation occurred on these incoming larvae by 8 piscivorous species, while no predation was observed during the second colonization event.