Sphyrna lewini is a viviparous shark that pups in shallow coastal waters. Given dramatic declines in the S. lewini Eastern Pacific population, it is essential to identify nursery grounds that could potentially increase the resilience of adult populations. Here, we provide evidence of a putative nursery ground for S. lewini at an oceanic island in the Galapagos Marine Reserve. A fortuitous finding of hammerhead shark pups in 2017 led to a series of focused surveys from 2018 onwards, using experimental fishing, baited remote underwater videos stations (BRUVS), and acoustic telemetry, to assess presence and residency patterns of this species at Puerto Grande: a shallow bay at the island of San Cristobal. We caught 66 individuals, of which we measured 54 (mean TL = 52.13 cm). Four individuals were fitted with ultrasonic tags and were detected on an array of 14 receivers in the bay for up to 93 days, showing a high residency index of at least 89%. We actively tracked a single individual for 3 h at night and a further hour a week later. Our results suggest that Puerto Grande is a key habitat for the development of the critically endangered S. lewini.

Sphyrna lewini是一种胎生鲨鱼，在沿海浅水区幼崽。鉴于S. lewini东太平洋种群的急剧下降，必须确定可能增加成年种群复原力的苗圃。在这里，我们提供了在加拉帕戈斯海洋保护区的一个海洋岛屿上推定的S. lewini苗圃的证据。2017 年偶然发现了双髻鲨幼崽，从 2018 年开始进行了一系列重点调查，使用实验性捕鱼、诱饵远程水下视频站 (BRUVS) 和声学遥测来评估该物种在格兰德港的存在和居住模式：圣克里斯托瓦尔岛的一个浅海湾。我们捕获了 66 个人，我们测量了其中 54 个（平均TL = 52.13 厘米）。四个人都安装了超声波标签，并在海湾中的 14 个接收器阵列上被检测到长达 93 天，显示出至少 89% 的高居住指数。我们在晚上主动跟踪了一个人 3 小时，一周后又跟踪了一个小时。我们的研究结果表明，Puerto Grande 是极度濒危的S. lewini发展的关键栖息地。