Faunal Composition and Spatiotemporal Dynamics of Tuna (Family: Scombridae; Tribe: Thunnini) Early Life Stages in the Oceanic Gulf of Mexico
Gulf of Mexico Oil Spill & Ecosystem Science Conference, New Orleans, Louisiana, February 4-7, 2019
Fishes within the family Scombridae (tunas, mackerels and bonitos) are of high ecological and economic value, as they are heavily targeted by commercial and recreational fisheries. In coastal and offshore ecosystems, adults are high-level predators, while larvae and juveniles 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 tuna early life stages have led to an “operational taxonomic unit” gap in our understanding of tuna ecology. Scombrids were collected across the Gulf of Mexico (GoM) during seven research cruises from 2010-2011, as part of the NOAA-supported Offshore Nekton Sampling and Analysis Program, and during five research cruises from 2015-2017, as part of the GOMRI-supported DEEPEND Consortium. Species composition, distribution, and abundance of tunas collected from the surface to 1500 m depth were characterized in relation to depth, time of year, and physical oceanographic features. Evidence of sampling gear selectivity was observed, with a MOCNESS collecting larvae predominantly, and a large, high-speed rope trawl catching only larger juveniles. Species-specific environmental preferences and seasonality were the main drivers of tuna spatial distribution patterns across the epipelagic GoM. Generalized additive models and distributional plots indicated that early life stages of coastal species (e.g., Euthynnus alletteratus) preferred productive continental shelf and slope environments (low salinity, high chlorophyll-a concentrations, nearer to shelf break), while oceanic species (e.g., Thunnus atlanticus) preferred oligotrophic habitats (high salinity, low chlorophyll-a concentrations, further from shelf break). Integrating aspects of scombrid ecology in neritic and oceanic environments improves management and conservation efforts for this highly important taxon.
Pruzinsky, Nina; Milligan, Rosanna; and Sutton, Tracey, "Faunal Composition and Spatiotemporal Dynamics of Tuna (Family: Scombridae; Tribe: Thunnini) Early Life Stages in the Oceanic Gulf of Mexico" (2019). Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures. 609.