Contrast in the density and biomass of fish in a reef system with different fishing intensity in the Mexican Caribbean
Abstract
A wide range of fish species are caught in reef fisheries. However, fishing efforts tend to be highly selective in favor of large species, which generally have low population growth rates, making them more vulnerable to overfishing. When the decline of large predators occurs, fishing efforts start to focus on catching species from lower trophic levels, which can cause a trophic cascade effect.The objective of this research was to detect changes in the density and biomass of fish communities in areas with different fishing intensity in the study area.This study was carried out in Banco Chinchorro in the Mexican Caribbean and analyze the effect of fishing intensity on fish density and biomass, comparing data obtained from visual censuses with dependent information of the fishery. Evidence was found of a relationship between high fishing exploitation and low levels of density and biomass for Epinephelus striatus, E. guttatus and Lachnolaimus maximus. The decline of predators of non-commercial species had no effect on the density and biomass of these species. Both the density and biomass of the fish in the areas studied were influenced by the presence of algae, octocorals, hydrocorals and by variations in the CPUE.This study detected that density and biomass have decreased in some species belonging to the Serranidae and Lutjanidae families in areas with high fishing intensity. On the other hand, little evidence was found that the density and total biomass of families of noncommercially important species increased through the decline of their predators. Finally, although attempts were made to reduce the effect of structural complexity on the density and biomass of fish species, it was found that certain benthic groups and CPUE explained the observed changes in the density and biomass of fish assemblages.