Data underlying the publication: "Distribution and ontogenetic habitat shifts of reef-associated shark species in the northeastern Caribbean"

Understanding how reef-associated sharks utilise coastal reef habitats throughout their ontogeny is essential for their effective management. In this study, we assessed the distribution of sharks in the northern Caribbean Netherlands (Saba, Saba Bank and St Eustatius) and ontogenetic shifts in habitat and depth use of the 2 most observed species: Caribbean reef shark Carcharhinus perezi and nurse shark Ginglymostoma cirratum. We used stereo baited remote underwater video (stereo-BRUV) surveys at 376 sites. A total of 126 shark sightings (6 species) were recorded, with C. perezi (n = 72) and G. cirratum (n = 42) most frequently observed. The probability of recording at least 1 shark per deployment ranged from 0.19 to 0.37 and is comparable with shark occurrences in the small number of other stereo-BRUV studies in the Wider Caribbean Region. Habitat type was the most important factor driving reef-associated shark occurrences, with the highest probability of observing C. perezi and G. cirratum in soft-coral habitat. Additionally, occurrences of C. perezi were significantly influenced by the management zone, with highest probabilities of occurrence in no-fishing zones. Almost all observed reef-associated sharks (95.6%) were juveniles, indicating that the study area may be a nursery area. Overall, both species were observed in deeper waters with increasing size, indicating ontogenetic shifts in depth use. Our findings imply that protected areas should not be limited to a single habitat or depth, but focus on protecting a large area with the range of habitats and depths necessary for reef-associated sharks to complete their life cycle.<br>

明确礁栖鲨鱼（reef-associated sharks）在整个个体发育周期内对沿岸礁生境的利用模式，是实现其有效保护管理的核心前提。本研究针对荷属加勒比海北部区域（萨巴岛、萨巴滩与圣尤斯特歇斯岛）内的鲨鱼分布情况，以及两种最常被观测到的物种——加勒比礁鲨（Carcharhinus perezi）与铰口鲨（Ginglymostoma cirratum）的生境与水深利用的个体发育变化展开了评估。研究团队在376个采样点开展了立体诱饵式远程水下视频（stereo-BRUV）调查。本次调查共计记录到126次鲨鱼目击事件，涵盖6个物种，其中加勒比礁鲨（n=72）与铰口鲨（n=42）为出现频次最高的物种。单次投放采样设备的鲨鱼目击概率介于0.19至0.37之间，该结果与泛加勒比海区其他少量立体诱饵式远程水下视频研究中记录的鲨鱼出现情况基本一致。生境类型是影响礁栖鲨鱼出现的最核心驱动因子，加勒比礁鲨与铰口鲨在软珊瑚生境中的观测概率最高。此外，加勒比礁鲨的出现概率还显著受管理分区的调控，在禁渔区内的出现概率达到峰值。本次观测到的礁栖鲨鱼中，95.6%均为幼体，表明该研究区域大概率为鲨鱼的育幼场。总体而言，两种鲨鱼的个体体型越大，其被观测到的栖息水域水深越深，这体现出二者在水深利用上的个体发育适应性变化。本研究结果表明，海洋保护区域不应仅局限于单一的生境类型或水深范围，而应着力保护涵盖足够生境多样性与水深梯度的大片海域，以满足礁栖鲨鱼完成整个生活史的全部需求。