Territoriality in the butterflyfish Chaetodon austriacus

Abstract

The ranging and feeding behaviour of the butterflyfish Chaetodon austriacus (Chaetodontidae) was studied at eight sites along the Red Sea coast of Saudi Arabia. This species was strongly paired and was found to defend territories intraspecifically, predominantly by display and non-aggressive 'advertisement'. Frequencies of overt aggression were relatively low. Two other species of butterflyfish were aggressed against occasionally, but this did not appear to be space-related. C. austriacus fed entirely on scleractinian corals, primarily Acropora, but included a variety of other genera in the diet. Territories appeared to be defended primarily for feeding and were significantly larger (1.6 times) at 10-15 m on the fore-reef slope than at the 1-2 m deep reef-edge. The availability of coral differed by a similar amount between depths, cover being 1.7 times greater in shallow water. Feeding rates did not differ significantly between depths. © 1992 Kluwer Academic Publishers.