Influence of Fishing Activity on Total Species Richness and Abundance Unevenness in Reef Fish Communities: A Case Study in a Brazilian Tropical Coral Complex

Abstract

The internal organization of reef-fish communities, particularly the species richness and the hierarchical structuring of species abundances, depends on many environmental factors, including fishing intensity and proportion of macroalgal cover which are expected to have determinant influences. However, reported studies on this topic are generally based on incomplete samplings (almost unavoidable in practice when dealing with highly uneven and species-rich communities), so that the derived results can be appreciably skewed. To overcome this difficulty, the incomplete samplings involved in this study were completed numerically through a reliable extrapolation procedure. This precaution provided a safe confirmation that reduced fishing activity and increased macroalgae cover both contribute to enhance the total species richness and to reduce the abundance unevenness in these reef fish communities. Yet, it is shown that this reduction of abundance unevenness is almost entirely attributable to the increase in species richness.