ABSTRACT: During January 1997 a die-off occurred in the sea urchin Meoma ventricosa in Curaçao, Netherlands Antilles. The mortalities were characterized by a progressive loss of spines and death. Microscopy of affected tissue revealed amorphous catch connective tissue of the spines, containing Gram-negative bacterial cells. Deliberate infections of the urchin Lytechinus variegatus with 1 of the 2 bacterial isolates resulted in signs similar to those observed in affected M. ventricosa in the field. The M. ventricosa die-off was restricted to an area of 3.5 km along the coast just down-current of the main harbor of Curaçao, and caused a significant decrease in population size of M. ventricosa in this area. In the impact area the percentage of affected urchins 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 water from the harbor increased the density of pathogenic bacterial strains causing the infection.

KEY WORDS: Mortality · Pathogenic bacterium · Sea urchin · Meoma ventricosa · Infection · Lytechinus variegatus

Published in DAO Vol. 38, No. 1 (1999) on October 11
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1999