Preliminary Survey of Fish Community Composition in Seagrass Habitat in Two Back-Reef Lagoons of the Southern Mexican Caribbean

Abstract

Little is known about seagrass fish communities in the southern Mexican Caribbean. Diurnal and nocturnal fish community structure in seagrass habitat were compared between back-reef lagoons using a visual census technique in a natural protected area within a national park (Xcalak) and an unprotected area (Mahahual). Seagrass fish communities differed significantly between the two locations in the daytime and Xcalak supported greater total fish densities. Species richness did not differ statistically between locations. Observed nighttime fish communities were characterized by low species richness and low fish abundance when compared to diurnal communities. Heavy tourist use and coastal development may have degraded seagrass habitat at Mahahual causing lower fish abundance. Also, proximity of seagrass to mangrove habitat in Xcalak may have led to increased abundance and differences in species composition between locations. More extensive analysis and monitoring of the relative functioning of back-reef habitats in these two systems is needed as coastal development and fishing pressure continue to threaten the area.