Eels at the Edge: Science, Status, and Conservation Concerns

Genetic Differentiation of the Japanese Eel

Mei-Chen Tseng, Wann-Nian Tzeng, and Sin-Che Lee


Abstract.—Polymorphic microsatellite loci as genetic markers were used to reject the null hypothesis of panmixia for the Japanese eel, Anguilla japonica. Observed heterozygosity showed slight heterozygote deficiencies over all loci. One of the eight loci (MS-4) in one sample showed departure from Hardy-Weinberg equilibrium. Unbiased Nei’s genetic distances ranged from approximately 0.058 to 0.134. A slight genetic differentiation was determined by FST and RST statistics when adjusted with Bonferroni correction. Although isolation by distance is often observed in marine species, its use as a null hypothesis seems questionable. Although the freshwater eel is categorized as a catadromous fish, the value of genetic diversity obtained fell within that of marine fishes. A higher correlation (P < 0.001) resulting from AMOVA supports the separation of Japanese eels into two management units: a low-latitude group (Shantou, Tanshui, and Fangliao) and a high-latitude group (Daecheon-myon, Yalu River, Hangzhou, and Mikawa Bay). Such a population subdivision will be useful for further applications of fisheries conservation and management in the northwestern Pacific Ocean.