The ark shell Scapharca subcrenata is a benthic bivalve distributed along the intertidal and subtidal zones of mud or silty sand shores of China,Japan,and Korea.It is a species of considerable economic value with a significant potential to further the development and diversification of aquaculture.Over the last two decades,the yields of this natural resources in China have decreased dramatically due to the marine reclamation works,reckless overcatching and environmental pollutions.The inter-simple sequence repeats DNA(ISSR)technique was applied to assess the genetic diversity among five stocks of Scapharca subcrenata(Jinzhou stock,Dandong stock,Jinzhou stock,Yingkou stocks and Zhanghe stock).Under predetermined optimal reaction conditions,137 ISSR sites were detected ranging from 200 bp to 2 500 bp with 12 primers.The number of amplified bands ranged from 9 to 15 in every individual.The experimental data were analyzed with POPGEN3.2 and MEGA2 software.The result showed that no evident differentiation existed among the five stocks,and they all belong to one community; the nearest phylogenetic relationship occurs between the Dandong stock and Zhuanghe stock,then between the Yingkou and Jinzhou groups in turn;the high level of mean heterozygosities suggests that the resource of Scapharca subcrenata was in good condition with high genetic variation.