Changes in species composition and abundance of fish larvae from the Gulf of Tehuantepec, Mexico

Abstract

The larval fish abundance and species composition of the Gulf of Tehuantepec are described based on the analysis of samples obtained from oblique zooplankton tows during summer 2007 and spring 2008. Changes in species composition and abundance between both periods were also described. A total of 145 taxa were obtained from which 73 were identified to species level, 43 to genus and 29 to family. The larval fish assemblage of the Gulf of Tehuantepec showed distinctive characteristics from other regions of the American Pacific, such as: A) a dominance of coastal-pelagic species (mainly Bregmaceros bathymaster); B) high diversity and abundance of shallow demersal species even along the oceanic stations of the study area; and C) a low proportion of mesopelagic species, an unusual condition in areas with narrow continental shelf. The diversity estimations suggest that Gulf of Tehuantepec is one of the most diverse ecosystems of the American Pacific, even as compared with other regions considered of highest diversity such as the Gulf of California. The high abundance, as well as the presence of the larval, juvenile and adult stages of B. bathymaster, suggests the importance of this region as a reproductive, nursery and recruitment for this species.