Study On Taxonomic Status And Genetic Diversity Of Chinese Ya Lujiang River Ayu

Ayu (Plecoglossus altivelis), is a small fish commonly found in China mainland. Its an osmeroid fish with an annual life history and its living habits stretch from the North China, up to Ya Lu Jiang River in Liao Ning Province, down South along the coastline to Bei Lunhe River in Guang Xi province. Due to its tasty flesh, ayu has highly commercial value at the local fishery markets in China and also because of the same reason, the ayu populations in China has been overfished in recent years. Overfishing, plus the destruction of ayu's natural inhabitats due to the construction of water conservancy, have seriously damaged the natural ayu populations in China. In some area, this species now is on the edge of extinction, although its amount was in great abundance even a decade ago. At present, ayu has already been written in the 'Red list of endangered fish species' in China and is being managed strictly. However, on the contrast, not much study has been done to this endangered species. In order to provide valuable and referrable data for the making of ayu's conservation policy and for the management of its shrinking populations, some necessary research on its genetic diversity as well as the taxonomic relationship among different geographic ayu populations need to be started in time. And the present study is also considered to be a good beginning to study the overall configuration of Chinese ayu and to clarify the relationships among natural ayu populations from different localities in China.In this study, with the utilization of advanced molecular marker method and the DNA sequencing technique, we studied both of the Ya Lujiang River ayu and Japanese ayu populations (the latter includes Plecoglossus altivelis altivelis subspecies with the amphidromous and landlocked forms and the Plecoglossus altivelis ryukyuensis subspecies) in order to find out the level of genetic diversity and the taxonomic status of Ya Lujiang River ayu population through the comparison of the results of DNA sequence analysis to both Ya Lujiang River ayu and Japan ayu populations. Our findings are as follows:...