Population structure of red snapper (Lutjanus campechanus) in US waters of the western Atlantic Ocean and the northeastern Gulf of Mexico

Population structure of adult red snapper (Lutjanus campechanus) from the southeastern coast of the United States (Atlantic) and the northeastern Gulf of Mexico (Gulf) was assessed using genotypes at 16 nuclear-encoded microsatellites and mitochondrial (mt)DNA haplotypes of the NADH dehydrogenase 4 (ND4) gene. Initial tests (F-ST-based, hierarchical AMOVA) of spatial genetic homogeneity within and between regions were non-significant, consistent with a single population or stock of red snapper in the Atlantic and Gulf. Inferences derived from other statistical approaches were consistent with genetic and/or demographic differences within and between the two regions. The estimated, average, long-term migration rate between the two regions (0.27%) was well less than the 10% rate below which populations can respond independently to environmental perturbation. Comparisons of global estimates of average, long-term effective size (N-eLT) with estimates from individual sample localities indicated genetic heterogeneity within both the Atlantic and Gulf. These results paralleled those of prior genetic studies of red snapper from the Gulf. Future genetics studies and other work on red snapper in both the Atlantic and Gulf should include approaches to identify demographically independent units within each region and assess their size, patterns of connectivity, and contribution to the fishery. Monitoring global and/or local effective size also should be considered. (C) 2015 Elsevier B.V. All rights reserved.