One hundred samples of two sea bass (Lateolabrax japonicus) populations were collected from Shantou and Qingdao coastal waters from June,1995 to May,1996. Seventeen isozymes coded by 31 gene loci were analyzed by starch gel electrophoresis and polyacrylamide gel electrophoresis,and allele frequencies of each loci in two populations were calculated. Seven loci,which were Mep-1,Pgm-1,Sdh,Gdh,Mpi,Est-1 and Est-4,were found polymorphic in Shantou population,the mean proportions of polymorphic loci was 22.6%. Pgdh was also polymorphic besides these loci in Qingdao population,the mean proportions of polymorphic was 25.8%. The observational value of heterozygosity (Ho) of polymorphic locus in Shantou population was 0.106—0.980，the expected value of heterozygosity (He) was 0.101—0.500,the genetic departure index (d value) was -0.181—0.960,d value of Est-4 in Shantou population was 0.960,obviously on the high side,this showed the number of hybrid individuals was more than expected. Ho in Qingdao population was 0.167—0.471,He was 0.210—0.556,d value was -0.399—-0.014. The average heterozygosities of Shantou and Qingdao populations were 0.079 and 0.099 respectively. The chi-Square test showed all polymorphic loci but Est-4 from Shantou were in Hardy-Weinberg equilibrium. The genetic deviation index agreed with the result of chi-Square test. The genetic similarity and genetic distance between the two populations were 0.9920 and 0.0080 respectively. It is concluded that the sea bass in Chinese coastal waters should belong to one species and two populations. The polymorphic loci proportions of the two populations was average among fishes,the average heterozygosities were high,reflected by high allele number of polymorphic loci. The genetic diversity level of Qingdao population was higher than that of Shantou population,because the former was distributed over a wider area and its population was larger. Various genetic indexes show that sea bass resource quality is still good,but overfishing should be prohibited to protect resources.%1995年6月—1996年5月分别在汕头及青岛收集共100尾鲈鱼生化样品，采用淀粉胶及聚丙烯酰胺凝胶电泳分析了鲈鱼17种同工酶，记录出31个基因座位，统计了基因频率。结果表明，2群体间遗传相似度和遗传距离分别为0.9920和0.0080。作者初步认为中国近海鲈鱼为1个种，分南、北2个种群。汕头种群多态座位比例为22.6%，青岛种群为25.8%。x2检验表明，2个群体多态座位等位基因频率除汕头的Est-4外均符合Hardy-Weinberg平衡。汕头与青岛种群平均杂合度分别为0.079和0.099，表明目前鲈鱼种质资源状况尚好，但当前捕捞鲈鱼苗的压力过大，应严格控制鲈鱼苗的捕捞，以免因滥捕仔稚幼鱼而导致资源衰竭。
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