Reproductive Ecology of Dragonfishes (Family: Stomiidae), the Dominant Vertically Migrating Mesopelagic Predators, in the Gulf of Mexico

Diel vertical migration is one of the prevailing fish behaviors in oceanic waters. Of the vertically migrating species, the dragonfishes (Stomiidae) are the dominant mesopelagic predators, preying primarily upon lanternfishes, which are the major zooplanktivorous migrators. While aspects of dragonfish feeding ecology have been quantified, little is known regarding their reproductive characteristics and production rate. In 2010–2011, a large-scale sampling program was initiated in the northern Gulf of Mexico over all four seasons using a discrete-depth sampling system and a large, commercial-sized midwater trawl. Of the dragonfishes collected on these cruises, gonads were dissected from 710 individuals belonging to 45 species. A gross examination of the gonads was performed using a visual, macroscopic assessment, as well as a microscopic, histological approach using hematoxylin and eosin stains. Using these methods, we will present data on size at first reproduction, sex ratios, hermaphroditism, and seasonality of production of the 13 dominant species collected. These data are essential for ecosystem-based modeling of global deep-pelagic ecosystems, which contain the overwhelming majority of earth’s fish biomass.