Novel toxic dinoflagellate causes epidemic disease in estuarine fish

A newly discovered dinoflagellate is responsible for major fish kills in US Atlantic Coast estuaries. We report that exposure to this dinoflagellate also causes skin ulcers in fish. Skin damage begins as epithelial erosion, which progresses to complete epithelial loss. Fish that recover from acute toxin exposure develop bacterial and/or fungal-infected skin ulcers that are typical of many spontaneous skin ulcer epidemics occurring in estuarine fish species along the Atlantic Coast of the US. Our data provide the first direct cause-and-effect link between a specific environmental stressor and a naturally-occurring, infectious disease in a fishery population.