Habitat Selectivity and Reliance on Live Corals for Indo-Pacific Hawkfishes (Family: Cirrhitidae)

Hawkfishes (family: Cirrhitidae) are small conspicuous reef predators that commonly perch on, or shelter within, the branches of coral colonies. This study examined habitat associations of hawkfishes, and explicitly tested whether hawkfishes associate with specific types of live coral. Live coral use and habitat selectivity of hawkfishes was explored at six locations from Chagos in the central Indian Ocean extending east to Fiji in the Pacific Ocean. A total of 529 hawkfishes from seven species were recorded across all locations with 63% of individuals observed perching on, or sheltering within, live coral colonies. Five species (all except Cirrhitus pinnulatus and Cirrhitichthys oxycephalus) associated with live coral habitats. Cirrhitichthys falco selected for species of Pocillopora while Paracirrhites arcatus and P. forsteri selected for both Pocillopora and Acropora, revealing that these habitats are used disproportionately more than expected based on the local cover of these coral genera. Habitat selection was consistent across geographic locations, and species of Pocillopora were the most frequently used and most consistently selected even though this coral genus never comprised more than 6% of the total coral cover at any of the locations. Across locations, Paracirrhites arcatus and P. forsteri were the most abundant species and variation in their abundance corresponded with local patterns of live coral cover and abundance of Pocilloporid corals, respectively. These findings demonstrate the link between small predatory fishes and live coral habitats adding to the growing body of literature highlighting that live corals (especially erect branching corals) are critically important for sustaining high abundance and diversity of fishes on coral reefs.

鹰䱵（Hawkfishes，Cirrhitidae科）为小型显眼的礁区捕食者，通常栖息于珊瑚群体的枝杈间，或隐匿于其中。本研究围绕鹰䱵的栖息地关联展开调查，并明确检验了其是否与特定类型的活珊瑚存在特异性关联。研究于印度洋中部查戈斯群岛延伸至太平洋斐济的6个采样点，探究了鹰䱵对活珊瑚的利用情况及其栖息地选择性。所有采样点共记录到隶属于7个物种的529尾鹰䱵，其中63%的个体被观测到栖息于活珊瑚群体之上或隐匿于其内。其中5个物种（仅Cirrhitus pinnulatus与Cirrhitichthys oxycephalus除外）均与活珊瑚栖息地存在关联。Cirrhitichthys falco偏好杯形珊瑚属（Pocillopora）物种，而Paracirrhites arcatus与P. forsteri则同时偏好杯形珊瑚属与轴孔珊瑚属（Acropora），这表明相较于基于当地该珊瑚属盖度的预期，鹰䱵对这些栖息地的利用比例显著偏高。栖息地选择偏好具有跨地理一致性，尽管所有采样点中杯形珊瑚属的总珊瑚盖度均未超过6%，但其仍是鹰䱵最常利用、且选择偏好最稳定的珊瑚类群。各采样点中，Paracirrhites arcatus与P. forsteri为优势物种，其种群丰度的变化分别与当地活珊瑚盖度及杯形珊瑚科（Pocilloporidae）珊瑚的丰度呈显著相关。本研究结果证实了小型捕食性鱼类与活珊瑚栖息地之间的关联，为日益增长的相关研究文献补充了新证据——这些文献均强调，活珊瑚（尤其是直立分枝状珊瑚）对维持珊瑚礁鱼类的高丰度与高多样性至关重要。