The smooth hammerhead shark Sphyrna zygaena is known to display a high degree of site fidelity to specific areas along the South African coastline. This species is vulnerable to overfishing and steep declines have been noted globally. In this study, a dual marker approach was used to investigate the spatial and temporal genetic variation of juvenile S. zygaena across the south and east coast of South Africa. Kinship of individuals was determined within and across cohorts from juvenile S. zygaena sampled in Mossel Bay, a putative pupping ground. Significant genetic differentiation (supported by F-statistics, multivariate analysis and Bayesian clustering) was evident between individuals sampled from the warm temperate south coast and the subtropical east coast, with asymmetric gene flow between regions. Distinct genetic composition was also revealed between sampling years, with different levels of relatedness within and among cohorts, indicating different temporal populations utilizing Mossel Bay annually. Based on these results, further investigation of S. zygaena populations across a wider region is warranted in order to make recommendations regarding conservation management of this vulnerable coastal shark.

众所周知，光滑的锤头鲨Sphyrna zygaena在南非海岸线的特定区域表现出很高的位置保真度。该物种容易过度捕捞，全球范围内下降幅度很大。在这项研究中，使用双重标记方法研究了南非南部和东部沿海地区的中华合子少年的时空遗传变异。确定了个体的亲属关系。在假定的小牧场Mossel湾采样。从温暖的温带南部海岸和亚热带东海岸采样的个体之间存在明显的遗传分化（受F统计，多变量分析和贝叶斯聚类支持），区域之间存在不对称的基因流。在抽样年之间还揭示了不同的遗传组成，队列内部和队列之间的相关程度不同，表明每年使用Mossel Bay的时间种群不同。根据这些结果，有必要对更广泛地区的zy。s。zygaena种群进行进一步调查，以便就这种脆弱的沿海鲨鱼的养护管理提出建议。