Replicate divergence between and within sounds in a marine fish: the copper rockfish (Sebastes caurinus)

Abstract

Understanding the factors that influence larval dispersal and connectivity among marine populations is critical to the conservation and sustainable management of marine resources. We assessed genetic subdivision among ten populations of copper rockfish (Sebastes caurinus) representing paired samples of outer coast and the heads of inlets in five replicate sounds on the west coast of Vancouver Island, British Columbia, using 17 microsatellite DNA loci. Overall, subdivision (F ST ) was low (F ST = 0.031, P < 0.001), but consistently higher between paired coast and head of inlet sites (mean F ST = 0.047, P < 0.001) compared to among the five coast sites (mean F ST = À0.001, P > 0.5) or among the five head of inlet sites (mean F ST = 0.026, P < 0.001). Heterozygosity, allelic richness and estimates of effective population size were also lower in head of inlet sites than in coast sites. Bayesian analysis identified two genetic groups across all samples, a single genetic group among only coast samples, two genetic groups among head of inlet samples and two genetic groups within each sound analysed separately. Head of inlet copper rockfish tended to be shorter with lower condition factors and grew more slowly than coast sites fish. Reduced physical connectivity and selection against immigrants in contrasting outer coast-head of inlet environments likely contribute to the evolution of population structure of copper rockfish. Based on genetic connectivity, coast sites appear to be better served by existing marine protected areas than are head of inlet sites.

Upwelling and eddies affect connectivity among local populations of the goldeye rockfish,Sebastes thompsoni(Pisces, Scorpaenoidei)

“…The present study found discordance between the mtDNA and msDNA loci results; the former suggested that Korean S. thompsoni comprised a single panmictic group, but the latter suggested that it comprised two genetically distinct clusters: Cluster 2 was predomi- null alleles produced very similar results of genetic differentiation as when they were included (Dick, Shurin, & Taylor, 2014;Lane, Symonds, & Ritchie, 2016;Underwood, Travers, & Gilmour, 2012).…”

“…The presence of null alleles, which caused an excess of homozygotes, can overestimate the levels of genetic differentiation (Chapuis & Estoup, ). However, many studies demonstrated that the analysis conducted excluding the loci with null alleles produced very similar results of genetic differentiation as when they were included (Dick, Shurin, & Taylor, ; Lane, Symonds, & Ritchie, ; Underwood, Travers, & Gilmour, ). Furthermore, it is known that null alleles could not change the overall patterns of genetic population revealed in ms loci analysis (Carlsson, ).…”

Genetic Assessment of a Black Rockfish, Sebastes schlegelii, Stock Enhancement Program in Lidao Bay, China Based on Mitochondrial and Nuclear DNA Analysis

“…This may be caused by heterozygote deficits, and there was heterozygote deficiency in 30 of the studied loci. Although null allele is also an important contributor for the heterozygote deviation in marine fish (Dick et al, 2014), it is unlikely that null allele is the main cause of the deviations observed in this study, because only a few loci had a high frequency of null alleles (e.g., RFs315, Kss18). The overall genetic diversity in S. schlegelii in this study was comparable to that previously reported using mtDNA and microsatellite markers (Zhang et al, 2016;Gao et al, 2018).…”

DoesGSTunderestimate genetic differentiation from marker data?

“…The overall mean G ST across loci is 0.027, very close to the F ST value 0.031 obtained by Dick et al . (). Single‐locus G ST and H S estimates are not correlated, with a correlation coefficient of 0.011 and a P value of 0.649.…”