Abstract
BackgroundThe gray snapper (Lutjanus griseus) has a tropical and subtropical distribution. In much of its range this species represents one of the most important fishery resources because of its high quality meat and market value. Due to this, this species is vulnerable to overfishing, and population declines have been observed in parts of its range. In recent decades, it has been established that knowing the level of genetic connectivity is useful for establishing appropriate management and conservation strategies given that genetic isolation can drive towards genetic loss. Presently the level of genetic connectivity between subpopulations of L. griseus of the southern region of the Gulf of Mexico and the Caribbean Sea remains unknown.MethodsIn the present study we analyze genetic structure and diversity for seven subpopulations in the southern Gulf of Mexico and the Mexican Caribbean Sea. Eight microsatellite primers of phylogenetically closely related species to L. griseus were selected.ResultsTotal heterozygosity was 0.628 and 0.647 in the southern Gulf of Mexico and the Mexican Caribbean Sea, however, results obtained from AMOVA and RST indicated a lack of genetic difference between the major basins. We also found no association between genetic difference and geographic distance, and moderately high migration rates (Nm = > 4.1) suggesting ongoing gene flow among the subpopulations. Gene flow within the southern Gulf of Mexico appears to be stronger going from east-to-west.ConclusionsMigration rates tended to be higher between subpopulations within the same basin compared to those across basins indicating some regionalization. High levels of genetic diversity and genetic flow suggest that the population is quite large; apparently, the fishing pressure has not caused a bottleneck effect.
Highlights
Establishing effective fisheries regulations is a complex and multidisciplinary task (INAPESCA, 2012)
He mean values for the Gulf of Mexico varied between 0.626 and 0.631 (Table 1), with the highest mean values in subpopulations C and Puerto de Veracruz (PV) (He = 0.631 both). He mean values observed in the Mexican Caribbean Sea region ranged between 0.641 and 0.655 (Table 2), with the highest mean values in subpopulations X and Punta Herrero (PH) (0.650 and 0.655, respectively)
We found high migration rates between subpopulations that were apparently counter to the flow of main currents (e.g., C–CH, CH–Bahia de Chetumal (BC) and PH–X)
Summary
Establishing effective fisheries regulations is a complex and multidisciplinary task (INAPESCA, 2012). It has been determined that delineating stock boundaries and knowing the level of genetic connectivity among stocks is useful for establishing appropriate management and conservation strategies (Villegas Sánchez et al, 2014). In much of its range this species represents one of the most important fishery resources because of its high quality meat and market value. The level of genetic connectivity between subpopulations of L. griseus of the southern region of the Gulf of Mexico and the Caribbean Sea remains unknown. Methods: In the present study we analyze genetic structure and diversity for seven subpopulations in the southern Gulf of Mexico and the Mexican Caribbean Sea. Eight microsatellite primers of phylogenetically closely related species to L. griseus were selected. High levels of genetic diversity and genetic flow suggest that the population is quite large; apparently, the fishing pressure has not caused a bottleneck effect
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