Ecological assessment of the coral reefs west of Cayo Largo del Sur, Cuba: 1998- 1999

Abstract

Cayo Largo del Sur. located in the southwest of Cuba south of the Gulf of Batabano. is a beach and diving resort, far from tho main island of Cuba and from Isla de la Juventud. Therefore, it is far from important permanent human settlements and from all agricultural and industnal development. However its western roefs are suffering a gradual deterioration process. Great scarcity of mesohertoivores (sea urchin Dtadema antttiarum, as well as scand and acanthund fcshes). and high nutrient concentrations were observed. As a consequence, an excessive algal and cyanofcactonal mat proliferation occurred. It has been reinforced by high temperatures in 1998 and by the smiplrfication of bottom ro!»of bocause of coral mortality caused by diseases and cyclones. Tho later provont tho ro-establishment of herbivore speoes populations. Finally, there seems to be a local nutrient generat>on in the reefs from the decomposition of groat amounts of algal detritus. Coinciding with high temperatures during the 1998 El Nino and La Nina an intense coral bleaching event took place, but with very limited mortality, The decline of coral cover in the deeper stations seems bo more determined by cumulative partial doaths of the coion.es, than by sudden death of whole colonies. Evidences of massive corai mortality were obsorvod only in the crests.