Non-native brittle star interactions with native octocoral epizoites: an endemic benthic ctenophore in peril?

Widespread and large populations of the non-native eastern Pacific ophiuroid brittle star Ophiothela mirabilis now occur in southeastern Florida, extending range this recently introduced species from southern Brazil northward to Caribbean Sea Florida. The Florida stars, representing two lineages, are epibionts on shallow (3–18 m depth), tropical/subtropical plexaurid (e.g., Eunicea spp., Muricea spp.) gorgoniid (Antillogorgia octocorals. scope study includes recent distributional records O. south field abundances relation cohabiting endemic ctenophore Coeloplana waltoni, behavioral observations ophiuroid, predatory amphipod Caprella penantis, as well a laboratory experiment testing effects native ctenophore. Individuals have been collected near St. Lucie Inlet, its northern-most by about 110 km since 2019. Two years sampling demonstrated significant declines native, benthic with increasing ophiuroid. Evidence suggests that is negatively affecting through interference competition, greatly aided abrasive armature calcareous spines, plates hooks. This detrimental effect justifies considering an invasive Sporadic intense predation caprellid also probably contributes ctenophore’s decline, but lesser extent than caused Adding risk extinction C. waltoni narrow requirement living octocorals hosts restricted distribution southeast Bahamas.