Fish diversity divergence between tropical eastern pacific and tropical western Atlantic coral reefs

Abstract

A comparison of fish diversity was carried out among 45 sites within four localities in the Mexican Tropical Western Atlantic (TWA) and Tropical Eastern Pacific (TEP) regions. Several taxonomical and functional diversity indices were considered, and their relationships with the coral cover were investigated in each locality. We found that despite a lower number of species, the localities within the Mexican TEP region had equal or even higher functional diversity than the localities in the Mexican TWA region where sites within the Caribbean Sea appeared particularly poorly diversified. Divergent relationships between fish diversity and coral cover were observed between the two oceanic regions. On the one hand, it tended to be positive in the TWA, and on the other hand, it was negative in the two TEP localities. This contrast may be explained by the low coral species richness and the homogeneous habitat (low structural complexity) provided by a high cover of coral in the TEP. This study highlighted how the fish assemblages can be functionally diversified within the TEP, a region generally considered poorly diversified, and how the relationship between fish diversity and coral cover may vary between oceanic regions.