Four oceanographic cruises were carried out between April 2011 and May 2013 on the continental slope of the southern Gulf of Mexico (GoM) in a depth range of 290 to 1200 m on board the R/V JUSTO SIERRA. A total of 91 trawls covered a total swept area of 170.49 hectares. We recorded 177 fish species belonging to 80 families. Fifteen species extended their distribution into the south of the gulf and 37 increased their depth ranges. Five species could have commercial importance:AphanopuscarboLowe, 1839;Hydrolagusmirabilis(Collett, 1904);Helicolenusdactylopterus(Delaroche, 1809);LophiusgastrophysusMiranda Ribeiro, 1915, andMerlucciusalbidus(Mitchill, 1818). The most abundant species werePolymixialoweiGünther, 1859;Parasudistruculenta(Goode & Bean, 1896);M.albidus,ChlorophthalmusagassiziBonaparte, 1840;DibranchusatlanticusPeters, 1876;Nezumiaaequalis(Günther, 1878);YarrellablackfordiGoode & Bean, 1896; andLaemonemabarbatulumGoode & Bean, 1883. High values of fish species richness, diversity, and evenness were registered throughout the study area. A high percentage of the fish species (97%) collected during this project are distributed in the entire GoM. Most of the species showed a wide depth distribution; however, a vertical zonation of species can be observed.
