Genetic and morphometric differences between yellowtail snapper (Ocyurus chrysurus, Lutjanidae) populations of the tropical West Atlantic

Abstract

Populations of Ocyurus chrysurus were compared genetically and morphometrically along the West Atlantic coast to test the null hypothesis of population homogeneity in the area. Brazilian populations were found to be differentiated in shape (canonical variates analysis; F [48,515] = 10.84, p < 0.0001). Analyses of mitochondrial DNA sequences (663 bp of the control region) did not show any differences between Brazilian populations but could detect differences between Brazilian and Caribbean (Belize) populations. The samples from Pernambuco differed significantly from the other Brazilian populations in allozyme frequencies (11 loci; F ST = 0.167; p < 0.05), but this may have resulted from the small number of samples analysed for that population. Sequence variation of Belize samples departed from neutral expectations (Fu's FS = -8.88; p < 0.001). A mismatch distribution analysis points to an ancient population expansion in that area. We conclude that the genetic data do not allow the rejection of the null hypothesis of panmixia for Brazilian yellowtail snapper populations which should be treated as a single genetic stock, with a latitudinal gradient on their morphology which probably results from phenotypic plasticity. On the other hand, there is a severe restriction to gene flow between O. chrysurus populations from the Caribbean and from the southwestern Atlantic.

Population Structure of Lutjanus purpureus (Lutjanidae - Perciformes) on the Brazilian coast: further existence evidence of a single species of red snapper in the western Atlantic

“…The magnitude of the recorded values (F/Ф ST = 0.236, P < 0.01) indicates only moderate genetic differentiation between the two snapper species, and may simply reflect the elevated polymorphism of the control region in these fish. Similar values were recorded in intra-population comparisons in lutjanids, including species from the western Atlantic (Ovenden et al 2004, Vasconcellos et al 2008.…”

“…The pattern of marked genetic homogeneity recorded here for L. purpureus appears to be typical of western Atlantic lutjanids, such as L. campechanus and Rhomboplites aurorubens in the Gulf of Mexico andFlorida (Bagley et al 1999, Garber et al 2004) and Ocyurus chrysurus in Brazil (Vasconcellos et al 2008). These species are behaviorally similar, demersal inhabitants of relatively deepwater habitats with rocky bottoms and/or coastal regions close to coral reefs (Allen 1985).…”

“…Unique haplotypes or haplotypes exclusive to a given population predominate. A similar pattern has been observed in other commercially-important lutjanid species, such as L. campechanus (Garber et al 2004), L. erythropterus (Zhang et al 2006), and O. chrysurus (Vasconcellos et al 2008). The relative abundance of unique haplotypes -a pattern common to all these species -may mean that many alleles are lost through harvesting, which will eventually affect the genetic diversity of stocks.…”

“…Information derived from the analysis of DNA fragments has been increasingly employed in conservation programs. In the specific case of the fish icthyofauna, a large number of studies have confirmed the effectiveness of the mitochondrial control region for the detection of gene flow between populations or species, and the understanding of genetic variation, phylogeographic patterns, and demographic history (Garber et al 2004, Sanz et al 2006, Zhang et al 2006, Gomes et al 2008, Rodrigues et al 2008, Vasconcellos et al 2008.…”

Population Structure of Denison?s barb, Puntius denisonii (Pisces:Cyprinidae): A Species Complex Endemic to the Western Ghats of India

“…The physico-chemical parameters could have an effect on the development of P. chalakkudiensis, although studies on reproductive, as well as foraging behavior, especially during its larval stage, are yet to be conducted. Many teleost populations exhibit morphological changes depending on the environment, and are still genetically homogenous, as reported in Brazilian populations of yellowtail snapper (Ocyurus chrysurus, Lutjanidae) [59], and in three different riverine populations of Liza abu, a mugilid species from Turkey [60]. However, in the present study, it may be difficult to point out which of the several biotic and abiotic factors contributed to this.…”