Cerqueira Sara C, Olbers Jennifer Margaret, Smith Grant, Carpenter Michelle, Pereira Mário J, Cliff Geremy
Department of Biology & CESAM, Universidade de Aveiro, Aveiro, Portugal.
Wildtrust, Pietermaritzburg, KwaZulu-Natal, South Africa.
PeerJ. 2024 Dec 20;12:e18736. doi: 10.7717/peerj.18736. eCollection 2024.
The spotted ragged-tooth shark, , is widely distributed in subtropical continental coastal seas. In South Africa, it is commonly found along the entire south and east coasts, including the iSimangaliso Wetland Park (IWP) in the far north, which is the largest Marine Protected Area on the South African coast. Pregnant females occur there for much of the year, with the largest aggregations in summer. It is here we used remote underwater photography (RUP), supplemented with surveys to photo-identify individuals, using unique spot patterns. Three known aggregation sites (Raggie Reef, Quarter-Mile Reef and Mushroom Rocks) were monitored over a 5-year period between 2018 and 2023. We photo-identified 574 individuals (569 females and five males) and registered 1,200 sightings, using images of the right flank. The identification of new individuals persisted throughout the study, with the discovery curve showing no signs of reaching an asymptote. A total of 97% ( = 550) of females observed were noticeably pregnant. Individuals were consistently identified across all sample years and at all three reefs, exhibiting movements among the three monitored sites. The reproductive cycle is generally regarded as 2 years, but some females appeared to have a 2-year rest between pregnancies. Raggie Reef, which lies in the sanctuary zone, emerged as the reef with the highest index of popularity, as individuals were present almost constantly (90% of the sampling days). The findings of this study confirm the crucial role that the IWP plays in the conservation of a species that is globally Critically Endangered.
斑点皱唇鲨广泛分布于亚热带大陆沿海水域。在南非，它常见于整个南部和东部海岸，包括最北部的伊西曼加利索湿地公园（IWP），该公园是南非海岸最大的海洋保护区。怀孕的雌性鲨鱼一年中大部分时间都出现在那里，夏季聚集数量最多。我们在此利用远程水下摄影（RUP），并辅以调查，通过独特的斑点图案对个体进行照片识别。在2018年至2023年的5年时间里，对三个已知的聚集地点（拉吉礁、四分之一英里礁和蘑菇岩）进行了监测。我们通过右侧腹的图像对574个个体（569只雌性和5只雄性）进行了照片识别，并记录了1200次目击情况。在整个研究过程中，新个体的识别一直在持续，发现曲线没有显示出达到渐近线的迹象。观察到的雌性中有97%（=550只）明显怀孕。在所有采样年份和所有三个礁石处都能持续识别出个体，它们在三个监测地点之间移动。繁殖周期通常被认为是2年，但有些雌性似乎在怀孕之间有2年的休息期。位于保护区内的拉吉礁成为最受欢迎的礁石，因为几乎每天（90%的采样日）都有个体出现。这项研究的结果证实了伊西曼加利索湿地公园在保护全球极度濒危物种方面所起的关键作用。
