Marine cleaning stations as hotspots for cryptobenthic reef fish.

Species interactions are fundamental drivers of biodiversity and often have benefits that extend beyond the directly interacting parties. Within coral reef ecosystems, cleaning mutualisms whereby ‘cleaner’ species remove ectoparasites from ‘client’ species at dedicated cleaning ‘stations’ are well documented, yet the indirect benefits remain relatively unknown. Specifically, cleaning stations may act as a refuge via predation mitigation, which could indirectly benefit functionally important reef fishes, such as cryptobenthic reef fishes (CRF). CRF are the most abundant group of reef fishes, display rapid turnover due to high predation and are vital to marine food webs. We provide novel evidence of an association between CRF communities and the presence of obligate cleaner goby (Elacatinus lobeli) cleaning stations in the Caribbean. Through in situ, visual surveys, we found a significantly higher abundance and diversity of CRF within the benthos around E. lobeli cleaning station coral heads, compared to the benthos outside of cleaning stations and around coral heads with no cleaners present. We highlight the importance of the indirect benefits of species interactions on third party species. Marine cleaning stations may help maintain functionally important fish communities, with cascading consequences for coral reef food webs and ecosystem functioning.