THE CRUSTACEAN DECAPOD COMMUNITIES OF THREE CORAL REEFS FROM THE SOUTHWESTERN CARIBBEAN SEA OF CUBA: SPECIES COMPOSITION, ABUNDANCE AND STRUCTURE OF THE COMMUNITIES

Abstract

The decapod communities of three coral reefs of the southwestern Caribbean Sea of Cuba (keys Juan Garcia, Cantiles and Diego Perez), at three different ecological levels (the reef lagoon, the reef flat and the outward slope) have been analyzed. A total of 2567 specimens belonging to 216 species were caught. The lagoons have the highest richness. The lower richness found in the reef flat may be explained because it is the more dis­ turbed area (higher hydrodynamic conditions) and there is a decrease in the diversity of substrates. The dominance, density, and biomass of the species vary in each ecological zone and key. These also depend on the sampling methodology, in relation with the adap­ tation and use of the resources by the species. The geometrical distributions show that there are many species with few specimens. The qualitative ordination and similarity analysis show that the more separated key could be differentiated from the other two, and that there is a closer relationship by ecological zones between the latter. All results point out the existence of a spatial gradient and a marked specificity in the use of the environ­ mental resources (i.e., shelters) by the species in the ecological zones of the studied keys. The Cuban continental shelf is delimited by extensive coral reef formations where many species of decapod live, of which some represent an important economic fishing resource (the Caribbean spiny lobster Panulirus argus and species of the genus Callinectes) and many other stand out in the food webs of the reef ecosystem. The aim of the present study is to give a first characterisation of the decapod crustacean communities of three coral reefs from tliree keys of the southwestern Caribbean Sea of Cuba at three different ecological levels (the reef lagoon, the reef flat complex and the beginning of the outward slope), to establish the faunal composition, the dominance, the structure of the communities and the differences between all analyzed zones and keys. There are studies on the general structure and organization of the decapod communi­ ties in biotopes or habitats constituted by sessile organisms, such as coraligenous or cal­ careous seaweed, sabellariid worms, corals, etc (Fausto-Filho and Furtado, 1970; Abele, 1976a,b; Abele and Patton, 1976; Gore et al, 1978; Reed et al, 1982; Garcia Raso and Fernandez, 1987; Lopez de la Rosa and Garcia Raso, 1992; Snelgrove and Lewis, 1989, among others). These studies have showed the importance of the substrate in the life of the species: as permanent or temporal shelter (for adult during the breeding time or for juveniles as nursery-growth), as food source, etc. (Abele, 1974,1976a; Garcia Raso, 1988). In addition, some of these papers give information on the ecological structure of the communities, as results of the species adaptation and survival strategies related with re­ production and growth (Garcia Raso, 1988), and the relationships with adjacent biotopes (Garcia Raso et al, 1996). Ecological studies on decapods of reef coral formations from Cuban archipelago are scarce (Zlatarski and Martinez-Estalella, 1980), the majority of them are check-lists or studies made in specific areas in which the different biotopes are analysed from a descrip