Genetic Analysis of Blue Marlin (Makaira nigricans) Stock Structure in the Atlantic Ocean

The genetic basis of stock structure of blue marlin (Makaira nigricans Lacepède 1802 ) in the Atlantic ocean was inferred from analyses of mitochondrial control region sequences. Blue marlin were collected in 1998 from 4 major geographic locations: western North Atlantic, Caribbean Sea, western South Atlantic and eastern Atlantic. Haplotype diversity (h) ranged from 0.99-1.0 and nucleotide sequence diversity (π) ranged from 0.11-0.13 within samples indicating that the control region harbors a significant amount of genetic variation. However, no significant differences were found in the spatial partitioning of genetic variation among the 4 col - lections; all pairwise φST values were negative and were therefore all taken as estimates around a true value of 0. As with previous studies of blue marlin, sequences were comprised of 2 distinct mitochondrial lineages separated by an average of 138 base pairs and φST between clades of 0.799 (P < 0.0001). These 2 lineages were present in similar frequencies across sampling locations. Genetic data from this study support management of Atlantic blue marlin as a single, Atlantic-wide stock.