Nocturnal observations of coral reef fishes along depth gradients

The foraging heights, at night, of some apogonid and holocentrid fishes are given. The noctural density of two species of planktivore (Chromis multilineatus and Clepticus parrai) along three depth (10–40 m) transects is figured. In the former species, density rapidly declined with depth. The use of the same shelter sites, at night, by individuals of the latter species is illustrated. The noctural abundance of three apogonid species is shown to be markedly higher than that observed during the day. The consistent use of two sponges for shelter is demonstrated.