Efecto del dragado de un canal de comunicación al mar (estero) sobre la asociación de peces en la Laguna Larga, Cayo Coco, Cuba

Abstract

Fish community and habitat of the estuarine channel connecting to the sea at Laguna Larga were characterized before and after the dredging conducted in 2012. For this purpose, the channel was divided into four sections: two initial sections near the sea (IA, IB) and two final sections near the lagoon (FA, FB). A total of 112 visual surveys were conducted by free diving. Shelter area, shade, water temperature, salinity, as well as current depth and velocity were measured in order to characterize the habitat. Spatial and temporal distribution of fish, species richness, density, and relative frequency were determined in each section, and results were related to habitat characteristics. A total of 22 species of fish distributed in 14 families were recorded.  The following were the dominant species: Abudefduf saxatilis, Halichoeres bivittatus, Stegastes leucostictus, and Lutjanus griseus. Fish density and richness were higher at the beginning of the channel than at the end, particularly Lutjanus griseus, which changed its niche preferences from the end of the channel (FB) to the beginning (IB). In addition, fish communities varied spatially and temporally. The restoration process resulted in decreased availability of shelter and consequently determined the decrease in density and species richness at the beginning of the channel. The most drastic changes in fish spatial and temporal pattern were associated with the final sections of the canal, which suffered the greatest changes in habitat.