文蛤、青蛤、菲律宾蛤仔和硬壳蛤隶属于软体动物门、双壳纲、帘蛤目、帘蛤科,广泛分布于朝鲜、日本及我国沿海,是我国重要的海水养殖贝类,2001年全国养殖产量已突破200万吨,仅次于牡蛎,在贝类中列第二位。目前,我国人工养殖蛤苗种大部分来源于天然,基本上没有经过系统的人工选育,其遗传基础还是野生型的,由于养殖上没有好的品种,一些种类经过累代养殖,出现生活力下降、个体变小和抗逆性差等问题,大面积死亡现象时有发 Clams, clams, clams and hard-shelled clams belong to the order of molluscs, bivalves, curtain clams and curtain clams. They are widely distributed in the coasts of North Korea, Japan and China and are important marine cultured shellfish in China. 2001 The annual national aquaculture production has exceeded 2000000 tons, second only to oysters, ranked second in shellfish. At present, most of the artificial clam cultivars in China are derived from natural plants and have basically not been artificially bred by humans. Their genetic basis is still wild type. Due to the lack of good breeds on breeding, some species undergo breeding generations with decreased viability , Smaller individuals and poor resistance and other issues, the phenomenon of large-scale death occurs