Faunal Composition and Spatiotemporal Dynamics of Tuna (Family: Scombridae) Early Life Stages in the Oceanic Gulf of Mexico

Scombrids are of high economic and ecological value in the Gulf of Mexico (GoM), as they are heavily targeted by commercial and recreational fisheries. In coastal and open-ocean environments, adult tunas are top predators, while larval and juvenile tunas serve as prey for numerous species. Much is known about the distribution and abundance of adult tunas, but high taxonomic uncertainty and limited knowledge regarding the distributional patterns of larval and juvenile tunas have led to an “operational taxonomic unit” gap in our understanding of tuna ecology. This analysis examined the spatiotemporal dynamics of larval scombrids collected in the northern GoM from April to September, 2011, as part of the NOAA-supported Offshore Nekton Sampling and Analysis Program. Generalized linear models were used to investigate the relationships between several environmental parameters and scombrid abundances in the epipelagic waters of the oceanic GoM. The dominant species collected in this study were Euthynnus alletteratus and Thunnus atlanticus . Euthynnus alletteratus abundances were highly seasonal and marginally influenced by fronts and day/night cycle. Higher abundances of T. atlanticus were associated with low chlorophyll a concentrations. Integrating aspects of scombrid ecology in neritic and oceanic environments will improve management and conservation efforts of this highly important taxon.