Dispersal during juvenile life stages drives the life-history evolution and dynamics of many marine vertebrate populations. However, the movements of juvenile organisms, too small to track using conventional satellite telemetry devices, remain enigmatic. For sea turtles, this led to the paradigm of the ‘lost years' since hatchlings disperse widely with ocean currents. Recently, advances in the miniaturization of tracking technology have permitted the application of nano-tags to track cryptic organisms. Here, the novel use of acoustic nano-tags on neonate loggerhead turtle hatchlings enabled us to witness first-hand their dispersal and behaviour during their first day at sea. We tracked hatchlings distances of up to 15 km and documented their rapid transport (up to 60 m min−1) with surface current flows passing their natal areas. Tracking was complemented with laboratory observations to monitor swimming behaviours over longer periods which highlighted (i) a positive correlation between swimming activity levels and body size and (ii) population-specific swimming behaviours (e.g. nocturnal inactivity) suggesting local oceanic conditions drive the evolution of innate swimming behaviours. Knowledge of the swimming behaviours of small organisms is crucial to improve the accuracy of ocean model simulations used to predict the fate of these organisms and determine resultant population-level implications into adulthood.
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机译：少年生命阶段的分散驱使许多海洋脊椎动物种群的生活史演变和动力学。然而，幼小的生物的运动太小而无法使用常规的卫星遥测设备进行跟踪，仍然令人费解。对于海龟来说，这导致了“迷失年代”的范式，因为孵化的鱼随着海流而广泛散布。近来，跟踪技术的小型化方面的进展已允许将纳米标签应用于跟踪神秘生物。在这里，在新生的龟孵化场上使用了新颖的声学纳米标签，使我们能够亲眼目睹它们在海上第一天的扩散和行为。我们跟踪了孵化场的距离，最长可达15 km，并记录了它们的快速运输（最远60 m min-1），表面电流流过它们的出生地。跟踪工作辅以实验室观察以监测较长时期的游泳行为，这突出了（i）游泳活动水平与体型之间的正相关，以及（ii）特定人群的游泳行为（例如夜间无运动），表明当地的海洋条件推动了游泳运动的发展。天生的游泳行为。了解小型生物的游泳行为对于提高海洋模型模拟的准确性至关重要，该模拟用于预测这些生物的命运并确定成年后对种群的影响。
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