Spread of diadema mass mortality through the Caribbean.

Populations of the ecologically important sea urchin Diadema antillarum suffered severe mass mortalities throughout the Caribbean. This mortality was first observed at Panama in January 1983; by January 1984 it had spread to the rest of the Caribbean and to Bermuda. The sequence of mortality events in most areas is consistent with the hypothesis that the causative agent was dispersed by major surface currents over large distances. However, some of the late die-offs in the southeastern Caribbean do not fit this pattern. Several lines of indirect evidence suggest that the phenomenon is due to a water-borne pathogen. If so, this is the most extensive epidemic documented for a marine invertebrate.