Distribution of batoid demersal assemblages on the continental shelf of the Gulf of Tehuantepec

Abstract

Information on the relationship between batoid demersal assemblages and environmental factors is scarce. We captured a total of 23414 batoids belonging to 16 species with bottom trawls at 243 sampling stations in the Gulf of Tehuantepec, Mexico. The species Urotrygon rogersi, Urotrygon chilensis and Narcine vermiculatus represented 70.1% of the abundance and 46.3% of the biomass. Five batoid assemblages were identified using hierarchical cluster and similarity profile analyses. Four assemblages were located at depths less than 40m and one assemblage was located at depths between 40 and 62m. The main batoid group was located in front of the most important lagoon complexes. The abundance biomass comparison method indicated that small species were dominant in terms of abundance in most assemblages. The set of environmental conditions and habitat characteristics (longitude, depth and sea surface temperature) present in the Gulf of Tehuantepec predicted important changes in the batoid community and affected its spatiotemporal distribution pattern.