BLANQUEAMIENTO CORALINO DE 1990 EN EL PARQUE NACIONAL NATURAL CORALES DEL ROSARIO (CARIBE, COLOMBIANO)

Abstract

At the beginning of June 1990 a coral-bleaching event was detected in the Islas del Rosario reefs, Colombian Caribbean. A preliminary survey of the Isla Grande northern barrier, and of the Cano Raton and Isla Pavitos south reefs slopes resulted in a list of 19 affected species, which includes scler-actinians, zoantideans and milleporins. Bleached colonies accounted for less than 10% of the total observed. The species most affected were Montastrea annularis and Pontes astreoides. The recovery process was followed during a five month period in 20 Montastrea annularis, 3 Acropora palmata and 3 Acropora cervicornis colonies . The bleached patches (injuries) of each colony were meassured, demarked with steel nails and their evolution monitored at monthly intervals. Total mortality was observed in 52% of the injures, incomplete recovery in 40%, and no apparent change in the remaining 8% of the colonies. The coral- bleaching event was coincident with an unusual rise in water temperature (31°C to 32°C) between May and June 1990. As the high temperatures lasted until October of the same year (>30°C), these are pressumed to be the main cause of the bleaching phenomenon. The possible role of light as a concomitant factor is-also discussed.