A scuticociliate causes mass mortality of Diadema antillarum in the Caribbean Sea

Science Advances
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Abstract

Echinoderm mass mortality events shape marine ecosystems by altering the dynamics among major benthic groups. The sea urchin Diadema antillarum, virtually extirpated in the Caribbean in the early 1980s by an unknown cause, recently experienced another mass mortality beginning in January 2022. We investigated the cause of this mass mortality event through combined molecular biological and veterinary pathologic approaches comparing grossly normal and abnormal animals collected from 23 sites, representing locations that were either affected or unaffected at the time of sampling. Here, we report that a scuticociliate most similar to Philaster apodigitiformis was consistently associated with abnormal urchins at affected sites but was absent from unaffected sites. Experimentally challenging naïve urchins with a Philaster culture isolated from an abnormal, field-collected specimen resulted in gross signs consistent with those of the mortality event. The same ciliate was recovered from treated specimens postmortem, thus fulfilling Koch’s postulates for this microorganism. We term this condition D. antillarum scuticociliatosis.

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Publication type Article
Publication Subtype Journal Article
Title A scuticociliate causes mass mortality of Diadema antillarum in the Caribbean Sea
Series title Science Advances
DOI 10.1126/sciadv.adg3200
Volume 9
Issue 16
Year Published 2023
Language English
Publisher Science
Contributing office(s) National Wildlife Health Center, St. Petersburg Coastal and Marine Science Center
Description eadg320, 10 p.
Other Geospatial Caribbean Sea
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