Poster Presentation 2024 Australian Marine Sciences Association Annual Meeting combined with NZMSS

Post-bleaching coral recovery may be moderated by the selective avoidance of corallivorous butterflyfish (Chaetodon rainfordi) (#713)

Isabella Marrable 1 2 , Juan C Ortiz 1 , Ziggy Marzinelli 2 , Will Figueira 2
  1. The Australian Institute of Marine Science and The University of Sydney, North Ward, QLD, Australia
  2. The University of Sydney and The Australian Institute of Marine Science, Stanmore, NSW, Australia

On undisturbed reefs the predation pressure of small-bodied corallivorous fish may not be a primary influence on the demographic rates of reef-forming corals. However, as coral reefs become disturbed through anthropogenic forcing, the chronic stress of this corallivory may impair the recovery of some colonies. it is not clear if corallivorous fish selectively avoid bleached corals due to a lower nutritional pay-off and as a result, may be moderating compounding predation stress post disturbance. We conducted a captive experiment to assess the preferential selectivity, predation intensity and impact upon coral growth of the corallivorous butterflyfish Chaetodon rainfordi when offered coral fragments with varying thermal stress history. Fragments of three common reef-building coral species were thermally preconditioned and were either predated upon or protected from predation. We observed a preference for coral genera Pocilloporidae and Acroporidae, and an apparent avoidance of visibly bleached colonies, with fish feeding at a higher rate across pigmented fragments. Corals that were exposed to predation grew significantly less and mortality was higher in this treatment. Our results indicate that corallivorous fishes may be moderating the post-disturbance recovery of reef-building corals by avoiding those already compromised by bleaching when pigmented colonies are available.