Life in colour: The influence of habitat colouration on the recruitment of coral reef fish

Settlement and early post-settlement survival of fishes are important processes on coral reefs and represent a major demographic bottleneck. While numerous studies have quantified habitat selection of recently-settled fish in terms of benthic composition or physical complexity, few have considered the potential role of habitat colouration. Using image-based analyses to identify key colours and benthic features that create these colours, we explored how recently-settled reef fish select various habitats with respect to their own colouration and habitat colour composition. We conducted visual surveys and took standardized photographs of the settlement locations of four species of damselfishes (f: Pomacentridae) at Lizard Island, Australia; two of which are bright yellow in appearance ( Pomacentrus amboinensis and P. moluccensis ) and two that are dark coloured ( P. adelus and P. chrysurus ). Each species occupied settlement habitats that had distinct colour profiles when compared to the wider reef environment and the other species examined. When species were grouped according to body colouration (dark vs yellow), there were also significant differences in settlement habitat colouration. These patterns appear to be driven primarily by the presence or absence of live coral, mainly Acropora spp., within their settlement location which add a range of unique hues not typical of other substrata. Thus, we provide evidence that habitat colouration, in addition to other physical and environmental attributes, may be important for shaping settlement patterns in coral reef fishes. If so, rapidly changing benthic compositions on coral reefs driven by the loss of live coral may ultimately favour certain coloured species that reside more successfully on drabber habitats which are becoming more common on contemporary reefs.