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Japanese whiting (Sillago japonica) is a relatively common marine fish inhabiting in the coastal shallow waters and the target species in an important commercial and recreational fishery. In this study, eighty-three specimens in five sites were collected along coasts of China and Japan, and genotyping-by-sequencing (GBS) technology was carried out to investigate the genetic structure and difference among them. Consistent with prior research conclusions, a relatively high genetic diversity was detected in S. japonica , and an increasing tendency of genetic variation level was detected as the latitude decreased in Chinese populations. Although estimated value of pairwise population differentiation (F ST) was low, the genetic heterogeneity analysis demonstrated a certain amount of genetic differentiation among local populations of S. japonica. Samples from Rushan were differentiated from other Chinese populations, but closely correlate with Ise Bay (IB) and Tokoy Bay (TB) populations, indicating gene flow between Rushan population (RS) and Japanese populations to a certain extent. Isolation by distance (IBD) analysis showed that genetic differentiation was significantly affected by geographical isolation. While, the results of isolation by environment (IBE) test showed that genetic distance was correlated with seawater salinity, which might be a selective pressure promoting genetic variation in S. japonica. Given the complex pattern of genetic differentiation of Japanese whiting among Chinese and Japanese populations, we suggested treating them as different management units in utilization of offshore fisheries resources. [ABSTRACT FROM AUTHOR]

Genetic diversity and population structure of Ammodytes personatus in the Northwestern Pacific were investigated for 16 collections using eight highly variable microsatellite loci. Microsatellite analyses gave strong support for the presence of two distinct groups of genotypes. Pleistocene glaciations can cause significant geographical differentiation in A. personatus populations. However, microsatellite data cannot confirm completely reproductive isolation between north group and south group. About half of comparison values within the first and second cluster were significant after sequential Bonferroni corrections. Routine oceanic currents associated with strong wind condition may provide an excellent chance for connectivity of among populations within clusters. However, gene flow can be restricted by marine gyres due to complex geographical characteristic. [ABSTRACT FROM AUTHOR]

Abstract: The silver catfish, Chrysichthys nigrodigitatus is an important food fish in the Niger Delta. To understand the genetic variations and population structure in Nigeria’s Niger Delta, eighty-eight individuals collected from 7 locations were analyzed based on amplified fragment length polymorphism (AFLP) analysis. A total of 243 bands were identified using 4 AFLP primer combinations. The average gene diversity was 0.1708 ± 0.1547 and Shannon’s information index was 0.2792 ± 0.2224. The pairwise F st values ranged from 0.133 to 0.796. The results of AMOVA analysis indicated that 19.03% of the genetic variation was contained among three groups. The gene flow estimates (Nm) demonstrated that different degrees of gene flow existed among populations ranging from 0.064 to 1.630. Two clades were recognized on the UPGMA tree. The results supported that freshwater or brackishwater habitat, limited long-distance dispersal of the adult and juveniles and physical barriers may be responsible for the current genetic structure. [Copyright &y& Elsevier]

Abstract Japanese grenadier anchovy, Coilia nasus , is a commercially important fish species in China. Three ecotypes (anadromous, landlocked and freshwater-resident populations) are distributed across its range. Due to anthropogenic activities such as overfishing and habitat deterioration, the stock status of this species has sharply declined. Clarifying population genetic structure and genetic relationships among ecotypes is essential for the conservation and stock management of C. nasus. Using 18 microsatellite loci, the distribution of genetic variation among 18 geographic populations (nine anadromous populations, four landlocked populations, and five freshwater-resident populations) was examined. High levels of genetic diversity were observed in all populations. Significant genetic differentiation among populations was detected and four genetic groups were identified, which might arise from current geographic segregation, different life-history strategy, and historical geographical factors. High assignment accuracies (≥85%) accessed for all populations suggested microsatellite loci can be used as an effective tool for discriminating the origin of individuals. Our study provided valuable information for conservation and sustainable management of C. nasus across its entire distribution range, and demonstrated the utility of microsatellite data to inform conservation units in highly exploited species. [ABSTRACT FROM AUTHOR]

Population genetics is a key component of policy development for fisheries management and conservation. Spatial genetic structure of the small yellow croaker ( Larimichthys polyactis ) has been previously reported, however, to date, no study has investigated temporal changes in genetic composition of this species. In the present study, temporal population-genetic structure was assessed by 15 microsatellite markers, and a temporal change in genetic composition of L. polyactis was observed. The temporal genetic variation of L. polyactis populations might be attributed to fishing-induced or ecological changes for this species. These results provided new perspectives on the population genetic structure of L. polyactis , which could have significant implications for sustainable management and utilization of this important fishery resource. [ABSTRACT FROM AUTHOR]

Abstract: The genetic diversity and population structure of the small yellow croaker (Larimichthys polyactis) were investigated based on seven microsatellite markers. Two hundred and twenty-six individuals were collected from ten locations from the Bohai Sea, the Yellow Sea and the East China Sea. Relatively high genetic variation (He = 0.826–0.873) and very low genetic differentiation (F st = 0.001–0.029) between populations were checked, which were attributed by high mutation rate, large population size, wide distribution and diverse habitats. L. polyactis had not undergone recent genetic bottleneck events, which was supported by Wilcoxon signed-rank test and mode-shift indicator of allele frequency distribution. UPGMA tree revealed that the cluster results had no connection with isolation by distance. The knowledge on genetic diversity and population structure will be crucial to establish appropriate fishery management for the species. [Copyright &y& Elsevier]