From shelf to shelf: assessing historical and contemporary genetic differentiation and connectivity across the Gulf of Mexico in Gag, Mycteroperca microlepis

• Published in: PloS one 2015-04, Vol.10 (4), p.e0120676-e0120676
• Main Authors: Jue, Nathaniel K, Brulé, Thierry, Coleman, Felicia C, Koenig, Christopher C
• Format: Article
• Language: English
• Subjects: Analysis; Animal Migration; Animals; Biodiversity; Biogeography; Biological evolution; Coasts; Connectivity; Conservation; Differentiation; Dispersal; Divergence; DNA, Mitochondrial - genetics; Ecological monitoring; Ecology; Evolution; Evolution, Molecular; Evolutionary biology; Female; Fish; Fisheries; Fisheries management; Fishery management; Fishing; Gene Flow; Genetic diversity; Genetic Drift; Genetics; Grasses; Gulf of Mexico; History; Laboratories; Male; Marine biology; Microsatellite Repeats - genetics; Microsatellites; Migration; Mitochondria; Mycteroperca microlepis; Perciformes - genetics; Phylogeography; Pleistocene; Population differentiation; Population dynamics; Population genetics; Populations; Spatial distribution; Species; Studies; Wildlife conservation
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0120676

Describing patterns of connectivity among populations of species with widespread distributions is particularly important in understanding the ecology and evolution of marine species. In this study, we examined patterns of population differentiation, migration, and historical population dynamics using microsatellite and mitochondrial loci to test whether populations of the epinephelid fish, Gag, Mycteroperca microlepis, an important fishery species, are genetically connected across the Gulf of Mexico and if so, whether that connectivity is attributable to either contemporary or historical processes. Populations of Gag on the Campeche Bank and the West Florida Shelf show significant, but low magnitude, differentiation. Time since divergence/expansion estimates associated with historical population dynamics indicate that any population or spatial expansions indicated by population genetics would have likely occurred in the late Pleistocene. Using coalescent-based approaches, we find that the best model for explaining observed spatial patterns of contemporary genetic variation is one of asymmetric gene flow, with movement from Campeche Bank to the West Florida Shelf. Both estimated migration rates and ecological data support the hypothesis that Gag populations throughout the Gulf of Mexico are connected via present day larval dispersal. Demonstrating this greatly expanded scale of connectivity for Gag highlights the influence of "ghost" populations (sensu Beerli) on genetic patterns and presents a critical consideration for both fisheries management and conservation of this and other species with similar genetic patterns.