Sea urchin Meoma ventricosa die-off in Curacao (Netherlands Antilles) associated with a pathogenic bacterium

During January 1997 a die-off occurred in the sea urchin Meoma ventricosa i n Curacao, Netherlands Antilles. The mortalities were characterized by a pr ogressive loss of spines and death. Microscopy of affected tissue revealed amorphous catch connective tissue of the spines, containing Gram-negative b acterial cells. Deliberate infections of the urchin Lytechinus variegatus w ith 1 of the 2 bacterial isolates resulted in signs similar to those observ ed in affected M. ventricosa in the field. The M, ventricosa die-off was re stricted to an area of 3.5 km along the coast just downcurrent of the main harbor of Curacao, and caused a significant decrease in population size of M. ventricosa in this area. In the impact area the percentage of affected u rchins was similar, but the percentage of dead urchins dropped from 83 to 0 % with distance down-current from the harbor. It is likely that polluted wa ter from the harbor increased the density of pathogenic bacterial strains c ausing the infection.