Genetic variation within and among range-wide populations of three ecotypes of the Japanese grenadier anchovy Coilia nasus with implications to its conservation and management

Abstract

Studies of range-wide populations can contribute to the comprehension of the relative roles of historical events and contemporary factors that influence genetic variation within and among populations. Japanese grenadier anchovy, Coilia nasus, is a commercially important fish, which widely distributes in the Changjiang River, the coasts of China and Korea, and the Ariake Sea of Japan. This species exhibits three life-history strategies (anadromous, landlocked and freshwater resident forms). Using two fragments of nuclear DNA, genetic variation within and among 18 populations across the rivers and coast of China and Ariake Sea of Japan was examined. Patterns of genetic diversity and divergence among populations varied widely across C. nasus’ range, and indicated the different effects of historical events and anthropogenic factors. Strong genetic divergence between freshwater resident populations and other populations suggested that historical geographical factors greatly influenced the genetic structure of C. nasus. Significant genetic differentiation observed among lakes in lower Changjiang River and Huaihe River might be probably influenced by hydraulic facilities. The population genetic structure among the three ecotypes revealed in the present study indicated an important role for environment variation, and the factors responsible for shaping C. nasus different life history strategies might also impact population structure.