The tuna meat is a nutritious food that possesses high content of protein, its low content of saturated fatty acids makes it a high demand food in the world. The Thunnus genus is composed of eight species, albacore (T. alalunga), bigeye (T. obesus), long tail tuna (T. tonggol), yellowfin tuna (T. albacares), pacific bluefin tuna (T. orientalis), bluefin tuna (T. maccoyii), Atlantic bluefin tuna ( T. thynnus) and blackfin tuna (T. atlanticus). The blackfin tuna (BFT) (Thunnus atlanticus) represent the smallest species within the Thunnus genus. This species inhabits the warm waters of the West Atlantic Ocean, from the shore of Massachusetts in the north, to Rio De Janeiro in Brazil. The first objective of this study was to evaluate the nutritional composition of BFT captured in the Gulf of Mexico, we determined ash, moisture, fat, protein and carbohydrates in BFT muscle and compared the obtained data with the nutritional reports from commercial tuna species including yellowfin tuna, Atlantic bluefin tuna and salmon (Salmo salar). Secondly, we report the genetic diversity and genetic differentiation of BFT within its geographical distribution range using the Cytochrome Oxidase I (COI) and control region sequenced data and from specimens collected in the Gulf of Mexico. We observed a nucleotide diversity π=0.001, 24 segregating sites and 10 parsimony informative. Within the CR we found nine different haplotypes π=0.044, 39 segregating sites, 16 parsimony informative sites. We concluded that according with the haplotype distribution there are differences among the BFT from the Gulf of Mexico and the North Atlantic compared to the South Atlantic. The Caribbean Sea is a migration point of the BFT, where all except the South Atlantic haplotypes were found.