Declines in the abundance of Chaetodon butterflyfishes following extensive coral depletion

Abstract

This study documented temporal variation in the abundance of butterflyfishes (Chaetodontidae) at Trunk Reef, on the central Great Barrier Reef, Australia, from May 2000 to March 2005. During this period, live coral cover declined by >90%, mostly due to severe coral bleaching. There were no short‐term changes (within 4 months) in the abundance of butterflyfishes following initial declines in live coral cover. Surveys conducted in 2005, however, revealed significant declines in the abundance of Chaetodon baronessa, Chaetodon lunulatus, Chaetodon trifascialis, Chaetodon plebeius and Chaetodon rainfordi, all of which are obligate hard‐coral feeders. In contrast, there was no significant change in the abundance of Chaetodon auriga, Chaetodon aureofasciatus, Chaetodon citrinellus, Chaetodon melannotus or Chaetodon vagabundus, which are much less reliant on scleractinian coral for food. Clearly, extensive coral depletion, such as that caused by severe coral bleaching, can have a major effect on the abundance of butterflyfishes. Specific responses of butterflyfishes varied according to their reliance on hard corals for food and their ability to utilize alternate prey types.