Data_Sheet_3_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可通过改变食物链和/或热条件，将海洋动物推向其生理耐受极限。此类事件通常会增加搁浅的风险。救助中心为报告处于困境中的动物提供了独特的机会，并通过卫星追踪康复个体，以识别潜在的新的栖息地并支持对这些濒危物种的有效保护。通过结合法国大西洋和英吉利海峡沿岸收集的观测（1988–2020）和追踪数据（2008–2020），本研究评估了比斯开湾是否为幼年海龟的生态陷阱或适宜的栖息地。最大的追踪个体向西迁移至远洋水域，可能朝着其出生海滩的方向，而较小的个体则保持在比斯开湾（BoB）内，穿越了更冷（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的方向不同，排除了对这些意外栖息地的被动推移。尽管比斯开湾在冬季可能从热力学上不适宜，但该区域预测的较高微中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，大部分观测记录的是搁浅的个体（75%），表明该区域也可能对体型较小的个体起到生态陷阱的作用，这些个体主要在冬季因冷水昏迷而搁浅。假定这些个体超出了物种的分布范围，我们的结果揭示了北东大西洋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，尤其是在这一阶段和如此温带纬度上。