Abstract

Few studies have looked at how the diet of piscivorous fish responds to changes in the abundance of their prey, despite the potential significance of predation as a factor regulating coral reef fish ecosystems. This twoyear study at Lizard Island on the northern Great Barrier Reef in Australia focused on two species of rock cod, Cephalopholis cyanostigma (Valenciennes, 1828) and Cephalopholis boenak (Bloch, 1790) (Serranidae), and tracked their consumption in two distinct environments (patch and contiguous reef). Rock-cod abundance was tracked concurrently with the abundance and family structure of their prey. The majority of the diet data was gathered from regurgitated samples, which roughly 60% of the prey ingested and were unrepresentative in composition.