Genetic Variation of Gray Triggerfish in US Waters of the Gulf of Mexico and South Atlantic Regions

The gray triggerfish, Balistes capriscus, is a reef fish that supports significant fisheries in offshore waters of the Gulf of Mexico and South Atlantic regions. Currently gray triggerfish are managed as a single stock in U.S. waters in the absence of adequate information on stock structure. Genetic variation among gray triggerfish in U.S. waters was surveyed using 17 microsatellite loci and sequences of a 617 base pairs fragment of the mitochondrial ND4 gene (mtDNA). The microsatellite dataset included genotypes of samples collected from six localities ranging from South Texas to South Carolina (47-78 fish per locality). Thirty specimens were assayed at the mitochondrial marker in all localities except East Texas.

Number of alleles and gene diversity statistics averaged 24.1 and 0.77 for microsatellites and 38 and 0.876 for mtDNA. Exact tests of population differentiation and spatial analysis of molecular variance did not reveal occurrence of significant heterogeneity among localities or groups of localities for both classes of markers. Significant positive spatial autocorrelation among samples collected within a neighborhood of 600km was detected. The dataset is currently being extended to increase sample size, improve geographic coverage, and to test temporal stability of observed patterns of spatial genetic variation.