Turbot (Scophthalmus maximus L., 1758) is a valuable commercial fish species classified as endangered. The conservation and sustainability of the turbot populations require knowledge of the population’s genetic structure and constant monitoring of its biodiversity. The present study was performed to evaluate the population structure of turbot along the Bulgarian Black Sea coast using seven pairs of microsatellites, two mitochondrial DNA (COIII and CR) and 23 morphological (15 morphometric and 8 meristic) markers. A total of 72 specimens at three locations were genotyped and 59 alleles were identified. The observed number of alleles of microsatellites was more than the effective number of alleles. The overall mean values of observed (Ho) and expected heterogeneity (He) were 0.638 and 0.685. A high rate of migration between turbot populations (overall mean of Nm = 17.484), with the maximum value (19.498) between Shabla and Nesebar locations, was observed. This result corresponded to the low level of genetic differentiation amongst these populations (overall mean Fst = 0.014), but there was no correlation between genetic and geographical distance. A high level of genetic diversity in the populations was also observed. The average Garza-Williamson M index value for all populations was low (0.359), suggesting a reduction in genetic variation due to a founder effect or a genetic bottleneck. Concerning mitochondrial DNA, a total number of 17 haplotypes for COIII and 41 haplotypes for CR were identified. The mitochondrial DNA control region showed patterns with high haplotype diversity and very low nucleotide diversity, indicating a significant number of closely-related haplotypes and suggesting that this population may have undergone a recent expansion. Tajima’s D test and Fu’s FS test suggested recent population growth. Pairwise Fst values were very low. The admixture and lack of genetic structuring found pointed to the populations analysed probably belonging to the same genetic unit. Therefore, a proper understanding and a sound knowledge of the level and distribution of genetic diversity in turbot is an important prerequisite for successful sustainable development and conservation strategies to preserve their evolutionary potential.

中文翻译：

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保加利亚黑海沿岸的三种大菱t（Scophthalmus maximus L.，1758）种群的遗传多样性和形态特征

菱（Scophthalmus maximus L.，1758）是一种有价值的商业鱼类，被列为濒危物种。菱turbo种群的保护和可持续性需要了解种群的遗传结构并对其生物多样性进行持续监测。本研究使用7对微卫星，2个线粒体DNA（COIII和CR）和23个形态学标记（15个形态学标记和8个meristic标记）对保加利亚黑海沿岸大菱turbo的种群结构进行了评估。对三个位置的总共72个标本进行了基因分型，并鉴定出59个等位基因。观察到的微卫星等位基因数目大于有效等位基因数目。观察到的（Ho）和预期的异质性（He）的总体平均值分别为0.638和0.685。观察到菱turbo种群之间的迁移率很高（总平均Nm = 17.484），在Shabla和Nesebar地点之间有最大值（19.498）。该结果对应于这些人群之间的遗传分化水平较低（总体平均Fst = 0.014），但遗传距离与地理距离之间没有相关性。在人群中也观察到了高水平的遗传多样性。所有人群的平均Garza-Williamson M指数值都很低（0.359），这表明由于创始人效应或遗传瓶颈而导致的遗传变异减少。关于线粒体DNA，共鉴定出COIII的17个单倍型和CR的41个单倍型。线粒体DNA控制区显示出具有高单倍型多样性和非常低的核苷酸多样性的模式，表明大量紧密相关的单倍型，并表明该人群可能最近经历了扩张。田岛的D检验和Fu的FS检验表明最近的人口增长。成对的Fst值非常低。发现的混杂和缺乏遗传结构表明所分析的种群可能属于同一遗传单位。因此，对大菱genetic遗传多样性的水平和分布有适当的了解和透彻的知识，是成功的可持续发展和保护战略以保持其进化潜力的重要前提。发现的混杂和缺乏遗传结构表明所分析的种群可能属于同一遗传单位。因此，对大菱genetic遗传多样性的水平和分布有适当的了解和透彻的了解，是成功的可持续发展和保护战略以保持其进化潜力的重要前提。发现的混杂和缺乏遗传结构表明所分析的种群可能属于同一遗传单位。因此，对大菱genetic遗传多样性的水平和分布有适当的了解和透彻的了解，是成功的可持续发展和保护战略以保持其进化潜力的重要前提。