Abstract

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 (?) 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 collections; all pairwise ?ST 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 ?ST 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.

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