Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.
J Exp Biol. 2019 Feb 6;222(Pt Suppl 1):jeb184077. doi: 10.1242/jeb.184077.
Diverse marine animals migrate across vast expanses of seemingly featureless ocean before returning as adults to reproduce in the area where they originated. How animals accomplish such feats of natal homing is an enduring mystery. Growing evidence suggests, however, that sea turtles and salmon imprint on the magnetic field of their home area when young and then use this information to return as adults. Both turtles and salmon have the sensory abilities needed to detect the unique 'magnetic signature' of a coastal area. Analyses have revealed that, for both groups of animals, subtle changes in the geomagnetic field of the home region are correlated with changes in natal homing behavior. In turtles, a relationship between population genetic structure and the magnetic fields that exist at nesting beaches has also been detected, consistent with the hypothesis that turtles recognize their natal areas on the basis of magnetic cues. Salmon likely use a biphasic navigational strategy in which magnetic cues guide fish through the open sea and into the proximity of the home river where chemical cues allow completion of the spawning migration. Similarly, turtles may also exploit local cues to help pinpoint nesting areas once they have arrived in the vicinity. Throughout most of the natal homing migration, however, magnetic navigation appears to be the primary mode of long-distance guidance in both sea turtles and salmon.
各种海洋动物在看似没有特征的广阔海洋中迁徙，然后成年后回到它们起源的地方繁殖。动物如何完成这样的出生地归巢壮举是一个持久的谜。然而，越来越多的证据表明，海龟和鲑鱼在年轻时会对家乡的磁场产生印记，然后利用这些信息在成年后返回。海龟和鲑鱼都有感知能力，可以检测到沿海地区独特的“磁场特征”。分析表明，对于这两组动物来说，家乡地区地磁场的细微变化与出生地归巢行为的变化相关。在海龟中，还检测到种群遗传结构与筑巢海滩上存在的磁场之间的关系，这与海龟基于磁场线索识别出生地的假设一致。鲑鱼可能使用双相导航策略，其中磁场线索引导鱼类穿过开阔海域进入家乡河流附近，然后化学线索完成产卵洄游。类似地，海龟一旦到达附近地区，也可能利用当地线索来帮助确定筑巢区域。然而，在大多数出生地归巢迁徙过程中，磁场导航似乎是海龟和鲑鱼长途导向的主要模式。
