PATTERNS OF PISCIVORY BY RESIDENT PREDATORY REEF FISH AT ONE-TREE REEF, GREAT-BARRIER-REEF

Patterns of piscivory were investigated among five abundant species of predatory fish at One Tree Reef, Great Barrier Reef, Australia. The g uts of two lutjanids Lutjanus carponotatus and Lutjanus fulviflamma, t wo labrids Cheilinus diagrammus and Thalassoma lunare, and a serranid Epinephelus quoyanus were examined for type, length, number and volume of prey at two times of the day: sunrise and sunset. Each of these sp ecies consumed fish, but only T. lunare and the two lutjanids consumed recruit-sized fish. This information is important because there is of ten scepticism as to whether large predators (>200 mm TL) such as lutj anids consume new recruits. Only in the lutjanids were there differenc es in the number and volume of prey present in the gut at sunrise and at sunset; at sunset, few lutjanid specimens contained prey, whereas a t sunrise 98% of specimens contained prey. This result, in conjunction with studies of nocturnal activity, suggest that patterns of predatio n pressure inferred from daylight observations of predator abundance m ay have little relevance to actual patterns of predation at local scal es.