fish larvae abundance as a function of oceanographic variables in GoM deep waters

We describe the larval occurrence and abundance of six fish species with contrasting life histories and examine their relationship with oceanographic variables during two seasons in the deep-water region (>1000 m) of the southern Gulf of Mexico based on 12 cruises (2011-2018). Given that Caranx crysos adults are neritic, larval presence close to the continental shelf indicates offshore cross-shelf transport to oceanic waters, which likely leads to mortality. Generalized additive models indicated C. crysos abundance  was not related with oceanographic variables, while that of Auxis spp. (with neritic and oceanic adults) was related to wind speed, sea surface temperature and height and surface chlorophyll a. The mesopelagic Benthosema suborbitale, Notolychnus valdiviae and Bregmaceros atlanticus were more abundant and broadly distributed, and higher abundance was found in conditions indicative of higher nutrient availability and productivity, suggesting greater feeding success and survival. The distribution of the epi- and mesopelagic Cubiceps pauciradiatus extended through the southern Gulf of Mexico, and was related to wind speed, SST, stratification and chlorophyll a. Our results suggest that the abundance of the neritic species in oceanic waters could be mediated by regional cross-shelf transport, while that of oceanic species is linked with productivity.