Herndon Solutions Group, LLC, NASA Environmental and Medical Contract, Kennedy Space Center, Merritt Island, Florida, United States of America.
Naval Undersea Warfare Center Division Newport, Newport, Rhode Island, United States of America.
PLoS One. 2023 Jun 16;18(6):e0286664. doi: 10.1371/journal.pone.0286664. eCollection 2023.
Offshore sand shoals are a coveted sand source for coastal restoration projects and as sites for wind energy development. Shoals often support unique fish assemblages but their habitat value to sharks is largely unknown due to the high mobility of most species in the open ocean. This study pairs multi-year longline and acoustic telemetry surveys to reveal depth-related and seasonal patterns in a shark community associated with the largest sand shoal complex in east Florida, USA. Monthly longline sampling from 2012-2017 yielded 2,595 sharks from 16 species with Atlantic sharpnose (Rhizoprionodon terraenovae), blacknose (Carcharhinus acronotus), and blacktip (C. limbatus) sharks being the most abundant species. A contemporaneous acoustic telemetry array detected 567 sharks from 16 species (14 in common with longlines) tagged locally and by researchers elsewhere along the US East Coast and Bahamas. PERMANOVA modeling of both datasets indicate that the shark species assemblage differed more across seasons than water depth although both factors were important. Moreover, the shark assemblage detected at an active sand dredge site was similar to that at nearby undisturbed sites. Water temperature, water clarity, and distance from shore were habitat factors that most strongly correlated to community composition. Both sampling approaches documented similar single-species and community trends but longlines underestimated the shark nursery value of the region while telemetry-based community assessments are inherently biased by the number of species under active study. Overall, this study confirms that sharks can be an important component of sand shoal fish communities but suggests that deeper water immediately adjacent to shoals (as opposed to shallow shoal ridges) is more valuable to some species. Potential impacts to these nearby habitats should be considered when planning for sand extraction and offshore wind infrastructure.
滨海沙坝是沿海修复项目和风力发电开发的理想沙源。沙坝通常支持独特的鱼类群落，但由于大多数海洋物种的高度流动性，它们对鲨鱼的栖息地价值在很大程度上是未知的。本研究结合多年的延绳钓和声学遥测调查，揭示了美国佛罗里达州东海岸最大的沙坝复合体相关鲨鱼群落的深度相关和季节性模式。2012-2017 年的每月延绳钓采样共捕获了来自 16 个物种的 2595 条鲨鱼，其中大西洋尖吻鲭鲨（Rhizoprionodon terraenovae）、黑鼻鲨（Carcharhinus acronotus）和黑鳍鲨（C. limbatus）是最丰富的物种。同期的声学遥测阵列检测到了来自 16 个物种的 567 条鲨鱼（与延绳钓共有的 14 个物种），这些鲨鱼是在美国东海岸和巴哈马由当地和其他地方的研究人员标记的。对两个数据集的 PERMANOVA 建模表明，鲨鱼物种组合在季节之间的差异大于水深，尽管这两个因素都很重要。此外，在一个活跃的挖沙工地检测到的鲨鱼群落与附近未受干扰的地点相似。水温、水清晰度和离海岸的距离是与群落组成最密切相关的栖息地因素。两种采样方法都记录了相似的单一物种和群落趋势，但延绳钓低估了该地区的鲨鱼育幼价值，而基于遥测的群落评估由于正在积极研究的物种数量而存在固有偏差。总的来说，这项研究证实了鲨鱼可以成为沙坝鱼类群落的一个重要组成部分，但表明紧邻沙坝的较深水域（而不是浅沙脊）对某些物种更有价值。在规划采砂和海上风力基础设施时，应考虑这些附近栖息地的潜在影响。
