Nursery use and construction-associated receiver detection patterns of the sicklefin lemon shark (Negaprion acutidens) at Dongsha (Pratas) Island

Shallow nearshore habitats can serve as nursery areas for coastal elasmobranchs but are increasingly exposed to coastal development. We used standardized population surveys, mark–recapture, acoustic telemetry, and passive acoustic monitoring to evaluate use of monitored shallow nearshore habitats by the sicklefin lemon shark ( Negaprion acutidens ) at Dongsha (Pratas) Island and to explore whether construction-associated underwater sound coincided with changes in receiver detections. Population surveys (2020–2022) were used to summarize CPUE, sex ratio, and size structure; mark–recapture data (2015–2022) were analyzed with an open-population model; acoustic telemetry (2016–2023) provided long-term detection context across a 14-station array, with individual-level summaries focused on a 2020–2022 core subset of 26 tagged sharks. Noise-related analyses were restricted to eligible 2022 deployment blocks with concurrent telemetry and passive acoustic monitoring. We recorded 740 sharks during standardized population surveys, of which ~ 90% were juveniles. Jolly–Seber modeling estimated a mean annual juvenile abundance of about 277 individuals. The telemetry archive contained > 360,000 detections. In the core tagged subset, juveniles were concentrated at eastern-coast and lagoon-mouth receivers, whereas small sharks and subadults were more broadly distributed. During construction-active intervals in the limited telemetry–noise overlap subset, lagoon-mouth detections declined and detections increased at eastern or southwestern stations. The monitored shallow nearshore habitats around Dongsha Island support a persistent juvenile nursery system for N. acutidens . Construction-associated sound coincided with station-specific changes in receiver detections, but this result should be interpreted cautiously because the overlap subset was small and acoustic detectability may also vary.