Population Genetic Structure And Molecular Phylogeography Of Konosirus Punctatus And Sardinella Zunasi

Evidence of fisheries management example and simulation study shows that fish population structure plays an important role in the fisheries management. Ignorance of population structures of fish population can lead to local overfishing and ultimately to severe declines of the population. Assessment of fish population genetic structure offer important insights into the fish population recovery and management. Various fish population structure patterns were observed in the Northwest Pacific. Climatic fluctuations during the Pleistocene period and the unique geographical character and ocean current pattern were considered to be responsible for the various genetic structure patterns. Fish species with various life history characters would show different population structure patterns in the interested area caused by their different responding to the geographical and hydrological factors.Morphological, mitochondrial DNA sequence, AFLP and ISSR markers were used to estimate the population structure and phylogeographic pattern of konosiro gizzard shad (Konosirus punctatus), the phylogenetic relationships among five species of Dorosomatinae was also discussed.Meristic and morphometric characters were compared by multivariate analysis for 10 populations of total 259 individuals; significant differences were found in means of most of these characters among 10 populations. PCA and post hoc test suggested a low level of variances between Chinese and Japanese populations.Fragments of mitochondrial DNA control region were sequenced for 183 individuals from 10 localities over most of the species'range. Two distinct lineages were detected, one in Chinese coastal waters and another in Japanese coastal waters, which might have been isolated and diverged during Pleistocene low sea levels. These results indicate that konosiro gizzard shad has limited dispersal ability. But the common over-wintering ground in Yellow sea lead to lack of genetic structure among the population in the Yellow Sea, and stronger ocean current around the coast causes high gene flow among the population in Japanese coast. But the independent migratory route lead to significant genetic variance between the population in Yellow Sea and Wenzhou population and Daya Bay population. A hyplotype clade composed by the private hyplotype was detected in Daya Bay population indicated a founded population existed in South China Sea.One hundred and sixty six konosiro gizzard shad individuals collected from 9 locations were used in the AFLP analysis. The result supported the two distinct and allopatric lineages detected by mt DNA sequences. Significant genetic variance was detected between the population in Yellow Sea and Daya Bay population. However, significant genetic differentiations were detected between Aomori population and other Japanese populations.Konosiro gizzard shad individuals collected from 5 locations were used in the ISSR analysis. The result strongly supported the result of mt DNA sequences. Deep divergences were detected between Japanese and Chinese groups. No significant genetic structure was detected between Qingdao and Zhoushan population, but significant genetic differentiations between Daya Bay population and the two Yellow Sea populations were detected. No significant genetic structure detected between Japanese populations.We present the phylogenetic relationships among five species of Dorosomatinae using partial sequences of the mitochondrial 16S rRNA and Cyt b genes. The results indicate a close phylogenetic relationship between Konosirus punctatus and Clupanodon thriss. In addition, a distant phylogenetic relationship was detected between genus Dorosoma, distributed in the America continent, and the 3 Indo-Pacific genera, including genera Konosirus, Clupanodon and Nematalosa.AFLP and ISSR markers were used to estimate the population structure and phylogeographic pattern of Sardinella zunasi.Seventy one S. zunasi individuals collected from five locations were used in the AFLP analysis, to examine the population genetic structure of S. zunasi. Both AMOVA and pairwise FST analysis detected significant population genetic structure between Chinese and Japanese populations, supporting separate stocks in this species. The UPGMA trees also detected the significant spatial structure of S. zunasi. The isolation by distance pattern was observed. The weaker but significant structures between Aichi and Kagawa populations of Japan might be impacted by the semi-enclosed coastal topography. However the result showed no significant genetic structure detected in Chinese group, indicated high level of gene flow among Chinese populations. Eighty seven S. zunasi individuals collected from five locations were used in the ISSR analysis. Similar to the AFLP results, strong genetic differentiation was revealed between Chinese and Japanese populations shown by both AMOVA and pairwise FST analysis, indicating separation of stocks of this species; and significant spatial structure among S. zunasi locations was shown by cluster analysis. It could be inferred that climate change during glaciations was responsible for the genetic differentiation. Isolation by distance pattern was observed, indicating the geographic distance might also lead to the genetic differentiation. However, no genetic structure has been observed within the populations of both Chinese coast and Japanese coast, indicating a high-level along-coast gene flow, which might be resulted from ocean current transport and common ground for over-wintering.