以前有报道称,安魂曲鲨鱼(Carcharhinus属)在地中海东部的海洋基础设施周围形成了大型聚集体。虽然这种行为可能会在个人层面提供健身优势,在人类改变的栖息地延长居住对人口持久性的影响尚待评估。在这项工作中,我们调查了以色列燃煤发电和海水淡化站附近鲨鱼的系统地理和人口组成。我们的目的是推断栖息地的使用和聚集行为背后的机制,并强调潜在的保护影响。我们取样,测量,并在2016年至2022年之间释放了70个人,以评估细胞色素C氧化酶I(COI)区域内的遗传变异性,并根据鲨鱼的大小和性别分布分析聚集的结构。此外,我们对在以色列另一个电站收集的死亡参考标本进行了综合计数,以使用上述技术补充物种鉴定。我们的发现表明,成年雌性暗色鲨鱼和雄性沙洲鲨鱼(Carcharhinusobscurus和Carcharhinusplumbeus,分别),每个物种包含两个COI单倍型。在昏暗的鲨鱼中,一种单倍型对应于印度-太平洋血统,另一个与大西洋血统相符。在沙洲鲨鱼中,我们观察到以前在地中海采样的单倍型,红海,西北印度洋,南非,另一种单倍型是我们研究地点独有的,在遗传上比在其他海洋盆地采样的序列更接近前者。这项研究首次表明了系统地理上不同的暗黑和沙洲鲨鱼谱系之间的同胞聚集,这表明地中海东部人类改变的栖息地可能会影响这些物种的分布。根据观察到的偏析模式,我们得出的结论是,该网站不能作为托儿所,分娩,或交配区,并讨论其他值得进一步研究的合理解释。最后,我们强调未来研究的重要方向以及我们的发现对管理和保护的影响。
Requiem sharks (genus Carcharhinus) have previously been reported to form large aggregations around marine infrastructures in the eastern Mediterranean Sea. While this behaviour may offer fitness advantages at the individual level, the implications of extended residency at human-altered habitats for population persistence have yet to be assessed. In this work, we investigated the phylogeographic and demographic composition of sharks near a coal-fired power and desalination station in Israel. Our aim was to infer habitat use and the mechanisms underlying the aggregation behaviour, and to highlight potential conservation impacts. We sampled, measured, and released 70 individuals between 2016 and 2022 to assess genetic variability within the cytochrome C oxidase I (COI) region and to analyse the aggregation\'s structure based on the sharks\' size and sex distribution. In addition, we performed meristic counts on a reference specimen collected dead at another power station in Israel to supplement species identification using the abovementioned techniques. Our findings indicate size-based sex
segregation of adult female dusky and male sandbar sharks (Carcharhinus obscurus and Carcharhinus plumbeus, respectively), with each species comprising two COI haplotypes. In the dusky shark, one haplotype corresponded to an Indo-Pacific lineage, and the other matched an Atlantic lineage. In the sandbar shark, we observed a haplotype previously sampled in the Mediterranean Sea, the Red Sea, the Northwest Indian Ocean, and South Africa, and another haplotype that was unique to our study site and genetically closer to the former than to sequences sampled in other ocean basins. This study provides the first indication of sympatric aggregation amongst phylogeographically distinct dusky and sandbar shark lineages, suggesting that human-altered habitats in the eastern Mediterranean Sea may influence the distribution of these species. Based on the observed
segregation pattern, we conclude that the site does not function as a nursery, parturition, or mating area, and discuss other plausible explanations that warrant further research. Finally, we highlight important directions for future research and the implications of our findings for management and conservation.