PDF(Pubmed)
Abstract：
The blue shark, Prionace glauca, is the most abundant pelagic shark in the open ocean but its vulnerability remains poorly understood while being one of the most fecund sharks. In the Mediterranean Sea, the blue shark is listed as Critically Endangered (CR) by the International Union for Conservation of Nature. The species is facing a strong decline due to fishing, and scientific data regarding its genetic structure and vulnerability are still lacking. Here, we investigated the genetic diversity, demographic history, and population structure of the blue shark within the Mediterranean Sea, from samples of the Gulf of Lion and Malta, using sequences of the mtDNA control region and 22 microsatellite markers. We also compared our mitochondrial data to previous studies to examine the Atlantic-Mediterranean population structure. We assessed the blue shark\'s genetic vulnerability in the Mediterranean basin by modelling its effective population size. Our results showed a genetic differentiation between the Atlantic and the Mediterranean basins, with limited gene flow between the two areas, and distinct demographic histories making the Mediterranean population an independent management unit. Within the Mediterranean Sea, no sign of population structure was detected, suggesting a single population across the Western and Central parts of the sea. The estimated effective population size was low and highlighted the high vulnerability of the Mediterranean blue shark population, as the estimated size we calculated might not be sufficient to ensure the long-term persistence of the population. Our data also provide additional evidence that the Gulf of Lion area acts as a nursery for P. glauca, where protection is essential for the conservation strategy of the species in the Mediterranean.
摘要：
蓝色的鲨鱼,PrionaceGlauca,是公海中最丰富的中上层鲨鱼，但它的脆弱性仍然知之甚少，同时也是最多产的鲨鱼之一。在地中海,蓝鲨被国际自然保护联盟列为濒危物种（CR）。由于捕鱼，该物种正面临着强烈的衰退，有关其遗传结构和脆弱性的科学数据仍然缺乏。这里,我们调查了遗传多样性，人口统计史,以及地中海蓝鲨的种群结构，来自狮子湾和马耳他的样本，使用mtDNA控制区的序列和22个微卫星标记。我们还将我们的线粒体数据与以前的研究进行了比较，以检查大西洋-地中海的人口结构。我们通过对蓝鲨的有效种群规模进行建模，评估了其在地中海盆地的遗传脆弱性。我们的结果显示了大西洋盆地和地中海盆地之间的遗传差异，两个区域之间的基因流动有限，和独特的人口历史使地中海人口成为一个独立的管理单位。在地中海,没有发现人口结构的迹象，暗示整个海洋西部和中部只有一个种群。估计的有效种群数量很低，突出了地中海蓝鲨种群的高度脆弱性，因为我们计算的估计规模可能不足以确保人口的长期持续存在。我们的数据还提供了额外的证据，表明狮子湾地区是青霉的托儿所，保护对于地中海物种的保护策略至关重要。
