Data_Sheet_5_Ecological Trap or Favorable Habitat? First Evidence That Immature Sea Turtles May Survive at Their Range-Limits in the North-East Atlantic.PDF

Unusual environmental events can push marine animals outside their physiological tolerances through changes in trophic and/or thermal conditions. Such events typically increase the risk of stranding. Rescue Centers offer a unique opportunity to report animals in distress and satellite track rehabilitated individuals to identify potential new habitats and support an effective conservation of these endangered species. By combining sightings (1988–2020) and tracking data (2008–2020) collected along the French Atlantic and English Channel coasts, our study assessed if the Bay of Biscay is an ecological trap or a favorable habitat for immature sea turtles. The largest tracked individuals migrated westward to pelagic waters, likely toward their natal beaches, while smaller individuals remained within the Bay of Biscay (BoB) and crossed colder (mean: 17.8 ± 3.0°C) but more productive waters. The turtles’ directions differed from the ones of ocean currents, excluding a passive advection to these unexpected habitats. Although the BoB might be thermally unsuitable in winter, the higher micronekton biomass predicted in this region could offer a productive foraging habitat for immature turtles. However, the majority of the sightings referred to individuals stranded alive (75%), suggesting this area could also act as an ecological trap for the smallest individuals that are mostly reported in winter suffering cold-stunning. Assumed to be outside the species range, our results reveal a potential foraging ground in the North-East Atlantic for these young turtles, confirming the crucial role of the rehabilitation centers and the need to continue prioritizing conservation of these endangered species, particularly vulnerable at this stage and at such temperate latitudes.

异常的生态环境事件，通过改变食物链和/或热力学条件，可能将海洋动物推至其生理耐受极限之外。此类事件通常会增加搁浅的风险。救助中心提供了独特的机遇，以报告处于困境中的动物，并通过卫星追踪康复个体，以识别潜在的新栖息地并支持对这些濒危物种的有效保护。通过结合1988年至2020年在法国大西洋沿岸和英吉利海峡沿岸收集的目击事件（1988-2020年）和追踪数据（2008-2020年），本研究评估了比斯开湾是否是幼年海龟的生态陷阱或适宜栖息地。最大的追踪个体向西迁移至远洋水域，可能向其出生海滩方向移动，而体型较小的个体则保持在比斯开湾（BoB）内，并穿越了较冷（平均：17.8 ± 3.0°C）但更具生产力的水域。海龟的移动方向与洋流方向不同，排除了对这些意外栖息地的被动平流。尽管比斯开湾在冬季可能从热力学上不适宜，但该地区预测的较高微浮游生物生物量可能为幼年海龟提供富有成效的觅食栖息地。然而，大部分目击事件所指的个体均为生还的搁浅者（75%），暗示该区域也可能成为体型最小的个体（主要在冬季因寒冷而搁浅）的生态陷阱。假设这些个体超出物种分布范围，我们的结果表明，东北大西洋存在这些幼年海龟的潜在觅食地，证实了康复中心的关键作用以及继续优先保护这些濒危物种的必要性，尤其是在这一成长阶段和此类温带纬度上。