Oceanic islands are productive ecosystems, and so have higher densities of many marine predators. We investigated the dynamics of elasmobranch and teleost predators in coastal waters off Réunion Island, Indian Ocean, using fisheries-independent data from a preventative shark fishing program from January 2014 to December 2019. We developed a moonlight index that calculates exact moonlight through incorporating lunar azimuth, elevation angle and island topography. We quantified spatial–temporal and environmental drivers of occurrence using zero-inflated mixed models and assessed species-specific catchability in the program. A consistent segregated pattern was observed with higher occurrence of all species at dusk and after-dusk associated with lower luminosity. Scalloped hammerhead sharks (Sphyrna lewini) and giant trevally (Caranx ignobilis) were found to patrol coastal waters earlier in the day than the other species. Tiger (Galeocerdo cuvier) and bull (Carcharhinus leucas) sharks showed high spatial segregation, potentially reducing competition. Teleost predators were found more frequently inside the coral reef environment of the Marine Protected Area but there was no clear pattern for sharks. Seasonality was observed for giant trevally, stingrays, bull sharks, and giant guitarfish (Rhynchobatus australiae), with higher presence during early winter periods related to turbidity, photosynthetically available radiation, and temperature. Inter-annual variation in catch rates suggested that juvenile tiger sharks might be replacing bull sharks in nearshore habitats, and the consequences for mitigation of shark bite hazard are discussed. Operational alternatives are proposed to enhance reducing the impacts of preventative shark fishing upon critically endangered species, improve their conservation and ensure local ecosystem balance.

海洋岛屿是生产性生态系统，因此许多海洋捕食者的密度更高。我们使用来自2014年1月至2019年12月的预防性鲨鱼捕捞计划的与渔业无关的数据，调查了印度洋留尼汪岛附近沿海水域中的弹性tele和硬骨捕食者的动态。我们开发了月光指数，通过结合月球方位角来计算精确的月光，仰角和岛屿地形。我们使用零膨胀混合模型量化了事件发生的时空和环境驱动因素，并在程序中评估了特定物种的可捕获性。观察到一致的隔离模式，黄昏和黄昏后所有物种的发生率较高，且发光度较低。扇贝锤头鲨（Sphyrna lewini）和大型tr（Caranx ignobilis）被发现在当天比其他物种更早地在沿海水域巡逻。虎鲨（Galeocerdo cuvier）和公牛（Carcharhinus leucas）鲨鱼显示出较高的空间隔离度，有可能减少竞争。硬骨鱼类在海洋保护区的珊瑚礁环境中被更频繁地发现，但鲨鱼没有明确的模式。观察到季节性存在着巨大的ev 、,鱼，公牛鲨鱼和巨型吉他鱼（澳大利亚Rhynchobatus），在冬季初期与浊度，光合有效辐射和温度相关的比例较高。捕捞率的年际变化表明，在近海生境中，幼虎鲨可能正在取代公鲨，并讨论了减轻鲨鱼咬伤危险的后果。提出了操作性替代方案，以增强减少鲨鱼预防性捕捞对濒临灭绝物种的影响，提高其保护水平并确保当地生态系统平衡的能力。