Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, Karnataka, India.
Department of Energy and Environment, TERI School of Advanced Studies, New Delhi, India.
PeerJ. 2023 Jun 1;11:e15396. doi: 10.7717/peerj.15396. eCollection 2023.
Considerable research exists on the life history traits, evolutionary history, and environmental factors that shape the population genetic structure of marine organisms, including sharks and rays. Conservation concerns are particularly strong for this group as they are highly susceptible to anthropogenic stressors due to a combination of life history traits including late maturity and low fecundity. Here, we provide a review and synthesis of the global phylogeography of sharks and rays. We examined existing data for 40 species of sharks belonging to 17 genera and 19 species of rays belonging to 11 genera. Median joining haplotype networks were constructed for each species for the mtDNA cytochrome C oxidase subunit I (COI), and an Analysis of Molecular Variance (AMOVA) was conducted to understand patterns of genetic diversity and structure across the three major ocean basins-the Indian, Atlantic and Pacific Oceans. Haplotype networks showed very shallow coalescence in most species, a finding previously reported for marine teleosts. Star topologies were predominant among sharks while complex mutational topologies predominated among rays, a finding we attribute to extremely limited dispersal in the early life history of rays. Population structuring varied amongst species groups, apparently due to differences in life history traits including reproductive philopatry, site fidelity, pelagic habitat, migratory habits, and dispersal ability. In comparison to reef-associated and demersal species, pelagic and semi pelagic species showed lower levels of structure between and within ocean basins. As expected, there is variation between taxa and groups, but there are also some broad patterns that can guide management and conservation strategies.
大量的研究已经关注到了影响海洋生物（包括鲨鱼和鳐鱼）种群遗传结构的生活史特征、进化历史和环境因素。由于生活史特征，如成熟晚和繁殖力低，鲨鱼和鳐鱼极易受到人为压力的影响，因此保护它们的问题尤为紧迫。在本研究中，我们对鲨鱼和鳐鱼的全球系统地理学进行了综述和综合分析。我们检查了 17 属 40 种鲨鱼和 11 属 19 种鳐鱼的现有数据。针对每个物种的线粒体 DNA 细胞色素 C 氧化酶亚基 I（COI）构建了中位数连接单倍型网络，并进行了分子方差分析（AMOVA），以了解三大洋（印度洋、大西洋和太平洋）的遗传多样性和结构模式。大多数物种的单倍型网络显示出非常浅的分歧，这一发现之前在海洋硬骨鱼类中已有报道。在鲨鱼中，星状拓扑结构占主导地位，而在鳐鱼中，复杂的突变拓扑结构占主导地位，我们认为这归因于鳐鱼早期生活史中极为有限的扩散。种群结构在不同的物种群体中存在差异，这显然是由于生活史特征的差异，包括生殖亲代定居、地点忠诚度、远洋栖息地、洄游习性和扩散能力。与礁相关和底栖物种相比，远洋和半远洋物种在大洋之间和内部的结构水平较低。正如预期的那样，不同的分类群和群体之间存在差异，但也存在一些广泛的模式，可以指导管理和保护策略。
