Genetic Variation and Stock Structure of Yellowfin Tuna in the Atlantic Ocean

The yellowfin tuna, Thunnus albacares, is a warm water pelagic species that supports major commercial and recreational fisheries throughout its range. In the Atlantic Ocean, multiple spawning locations have been reported, but a single stock is assumed during assessment efforts based on the observation of a continuous distribution of the species in tropical waters and the results of mark-recapture studies. Information on genetic stock structure is essential for management of this resource but is still very limited. In this work, 24 new microsatellite markers were developed and characterized through analysis of the genotypes of 35 yellowfin tuna specimens. Fifteen of the microsatellites were selected based on their suitability for population genetic studies. Specimens were collected from 4 locations in the Western Atlantic (Northern Gulf of Mexico, U.S. Mid Atlantic and North Atlantic regions, and Venezuela) and two localities in the Eastern Atlantic (Ghana and Senegal). Sexually mature adults were targeted in priority during sampling in order to provide information on the breeding structure of the species. Samples are currently being genotyped and will be incorporated in an analysis of stock structure and connectivity in the Atlantic Ocean.