Bathymetric distribution and feeding habits of two sympatric cheilodactylid fishes at Miyake-jima,Japan

Habitats including depth, diurnal activity patterns, and diets of the two cheilodactylid fishesCheilodactylus zonatus andC. zebra were studied at Igaya Bay, Miyake-jima, Japan. Both species occurred at nearly equal densities in identical habitats and depths. They preyed on benthonic organisms from early morning to shortly before sunset, when feeding activities decreased remarkably and intraspecific social behavior greatly increased. Gut analyses showed a high degree of dietary overlap, but proportions of food items in their diets differed slightly.C. zonatus was more of a food generalist thanC. zebra, showing a higher niche breadth value.C. zebra tends to feed on epifauna, especially gammaridean amphipods and decapods, whileC. zonatus takes both epifauna and infauna including polychaetes.