Isolation and characterisation of 18 polymorphic microsatellite loci for black marlin (Istiompax indica) and their utility for Pacific billfish species

We present the isolation and characterisation of 18 polymorphic microsatellite loci with perfect 3 and 4-bp repeats for the black marlin Istiompax indica using Ion Torrent next-generation sequencing techniques. Usefulness of these markers for genetic studies was assessed by screening 16 specimens collected throughout the Indo-Pacific basin for this broadly distributed and exploited species. A total of 30 black marlin from the West Coral Sea were genotyped producing between 2 and 20 alleles per locus (mean 5.27) with expected heterozygosity (H_E) ranging from 0.095 to 0.843. The genotypic distribution of all loci conformed to Hardy-Weinberg expectations with no evidence of null alleles. Evaluations of cross-species amplification of these markers on five additional Pacific billfish species indicates the utility of these markers for genetic studies of other Istiophorids.