Department of Ocean Sciences, Rosenstiel School of Marine & Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149-1098, USA.
Institute of Marine Research, Marine Ecosystem Acoustics Research Group, Austevoll Research Station, Sauganeset 16, 5392 Storebø, Norway.
Sci Adv. 2017 Jun 9;3(6):e1602007. doi: 10.1126/sciadv.1602007. eCollection 2017 Jun.
The European eel () has one of the longest migrations in the animal kingdom. It crosses the Atlantic Ocean twice during its life history, migrating between the spawning area in the Sargasso Sea and Europe, where it is widely distributed. The leptocephalus larvae drift with the Gulf Stream and other currents for more than a year and metamorphose into glass eels when they arrive on the continental shelf and move toward coastal areas. The mechanisms underlying glass eel orientation toward the coast and into freshwater systems are poorly known. However, anguillid eels, including the glass eel life stage, have a geomagnetic sense, suggesting the possibility that they use Earth's magnetic field to orient toward the coast. To test this hypothesis, we used a unique combination of laboratory tests and in situ behavioral observations conducted in a drifting circular arena. Most (98%) of the glass eels tested in the sea exhibited a preferred orientation that was related to the tidal cycle. Seventy-one percent of the same eels showed the same orientation during ebb tide when tested in the laboratory under a manipulated simulated magnetic field in the absence of any other cue. These results demonstrate that glass eels use a magnetic compass for orientation and suggest that this magnetic orientation system is linked to a circatidal rhythm.
欧洲鳗鲡（）拥有动物界最长的迁徙路线之一。在其生命周期中，它会在马尾藻海的产卵区和广泛分布的欧洲之间进行两次跨越大西洋的洄游。柳叶鳗幼虫随墨西哥湾流和其他海流漂流一年多，到达大陆架后变成玻璃鳗，并向沿海地区移动。玻璃鳗向海岸和淡水系统定向的机制知之甚少。然而，包括玻璃鳗生命阶段在内的鳗鲡类具有地磁感应能力，这表明它们可能利用地球磁场来定向到海岸。为了验证这一假设，我们在一个漂流的圆形竞技场中结合使用了独特的实验室测试和现场行为观察。在海中测试的大多数（98%）玻璃鳗表现出与潮汐周期相关的偏好定向。当在实验室中在没有任何其他线索的情况下，在人为模拟磁场下进行退潮测试时，同一批鳗鱼中有 71%表现出相同的定向。这些结果表明，玻璃鳗使用磁罗盘进行定向，并表明这种磁性定向系统与潮汐节律有关。
