Biogeographical affinities of fish associated to the shrimp trawl fishery in the Gulf of Tehuantepec, Mexico

Fish by-catch of the Gulf of Tehuantepec shrimp fishery is mainly composed of several species that are discarded in their majority. Fish by-catch species composition, distribution and biogeographical affinities were analyzed through 15 cruises carried on the continental shelf at a depth of 12 to 70 m during 2003, 2004, 2005 and 2013. Fish by-catch was represented by 58 families, 129 genera and 242 species. The families Haemulidae, Sciaenidae, Paralichthyidae, Gerreidae and Carangidae accounted for >70% of the catch. Haemulopsis axillaris, Syacium ovale, Selene peruviana, Diapterus peruvianus, Larimus acclivins and Stellifer erycimba were the most frequent species at <40 m depth (inner shelf), and Prionotus stephanophrys, Scorpaena russula, Porichthys analis and Synodus scituliceps were dominant at 40−60 m depth (outer shelf). Analysis of biogeographical affinities showed that 36.1% of species had a wide distribution, from San Diego Province to the Panamic Province, while 13.2% had a restricted distribution in the Mexican and Panamic Provinces. The ichthyofaunal composition was markedly influenced by the local environment and seasonal conditions.