Local extinction of a coral reef fish explained by inflexible prey choice
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While global extinctions of marine species are infrequent, local extinctions are becoming common. However, the role of habitat degradation and resource specialisation in explaining local extinction is unknown. On coral reefs, coral bleaching is an increasingly frequent cause of coral mortality that can result in dramatic changes to coral community composition. Coral-associated fishes are often specialised on a limited suite of coral species and are therefore sensitive to these changes. This study documents the local extinction of a corallivorous reef fish, Oxymonacanthus longirostris, following a mass bleaching event that altered the species composition of associated coral communities. Local extinction only occurred on reefs that also completely lost a key prey species, Acropora millepora, even though coral cover remained high. In an experimental test, fish continued to select bleached A. millepora over the healthy, but less-preferred prey species that resisted bleaching. These results suggest that behavioural inflexibility may limit the ability of specialists to cope with even subtle changes to resource availability.
KeywordsCoral reef fish Oxymonacanthus longirostris Coral bleaching Corallivory Disturbance Local extinction
Special thanks to Reef HQ Aquarium for logistical support. Financial support was provided by the Marine and Tropical Science Research Facility (MTSRF) and the ARC Centre of Excellence for Coral Reef Studies. This work was conducted under GBRMPA permit G10.33757.1 and ethics permit A1399.
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