The molecular genetic associations between populations of sand seatrout (Cynoscion arenarius) and silver seat-rout (C. nothus) have not been specifi-cally examined on a large scale with DNA methods despite the close ties between the respective fisheries for the two species. In particular, the pos-si...
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.508.5279 http://fishbull.noaa.gov/1071/anderson.pdf |
| Summary: | The molecular genetic associations between populations of sand seatrout (Cynoscion arenarius) and silver seat-rout (C. nothus) have not been specifi-cally examined on a large scale with DNA methods despite the close ties between the respective fisheries for the two species. In particular, the pos-sibility of contemporary hybridization or historical admixture between these species remains to be explored by using a large panel of unlinked DNA markers. Sand and silver seatrout are so morphologically similar that they are collectively known as white trout by fishermen (Ginsburg, 1931). Both species are abundant throughout the Gulf of Mexico (hereafter, GOM); the distribution range for sand seatrout extends into the Atlantic Ocean, north to Georgia, and the distribution range for silver trout extends to Massachu-setts (Hildebrand and Schroeder, 1928; Cordes and Graves, 2003). These seat-rout make up a modest proportion of bycatch in shrimp and other commer-cial trawl operations (Warren, 1981), although commercial landings have decreased dramatically in the last 30 years (Fig. 1). Weinstein and Yerger (1976) completed perhaps the most comprehensive study of molecular evo-lution in the genus Cynoscion; they assessed protein electrophoresis vari-ants in all four western North Atlantic species (C. arenarius, C. nothus, spot-ted seatrout [C. nebulosus], and gray weakfish [C. regalis]). Although these methods provided some insight into the evolutionary relationships among the species, the data of Weinstein and Yerger (1976) were insufficient to answer direct questions about rates of contemporary and recent historical gene flow within and among Cynoscion species. Enzyme electrophoresis has since been superceded by DNA-based methods on a broad scale. Microsatel-lite markers are likely more sensitive for studies involving high rates of gene flow and low levels of population iden-tity (Wright and Bentzen, 1994). This is particularly true for marine fishes, whose populations are often charac-terized by enormous census sizes and ... |
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