Orientation of hatchling loggerhead sea turtles to regional magnetic fields along a transoceanic migratory pathway
Orientation of hatchling loggerhead sea turtles to regional magnetic fields along a transoceanic migratory pathway
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DOI：
10.1242/jeb.055921
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发表时间：
2011-08-01
影响因子：
2.8
通讯作者：
Lohmann, Kenneth J.
中科院分区：
文献类型：
--
作者：
Fuxjager, Matthew J.;Eastwood, Brian S.;Lohmann, Kenneth J.
年轻的红海龟（Caretta Caretta）来自美国佛罗里达东海岸，在北大西洋环流（马尾藻海周围的循环洋流系统）周围进行跨洋迁徙。先前的实验表明，当暴露在与迁徙路线上五个相隔很远的地方的磁场相同的磁场中时，红海龟的幼崽会做出反应，游向在每种情况下都能帮助海龟留在环流中并沿着迁徙路线前进的方向。在这项研究中，幼崽被暴露在几个额外的磁场中，这些磁场存在于环流北部边界沿线或之外。小海龟对存在于环流内的磁场的反应是沿着与它们在每个地点的迁徙路线一致的方向游泳，而海龟暴露在存在于环流以北的磁场中，其方向在统计上与随机没有区别。这些结果与第一次入海的红海龟拥有一个导航系统的假设是一致的，在这个导航系统中，一系列的区域磁场依次触发定向反应，帮助海龟沿着迁徙路线导航。相比之下，幼龟可能无法对超出海龟正常地理范围的区域做出反应。
Young loggerhead sea turtles (Caretta caretta) from the east coast of Florida, USA, undertake a transoceanic migration around the North Atlantic Gyre, the circular current system that flows around the Sargasso Sea. Previous experiments indicated that loggerhead hatchlings, when exposed to magnetic fields replicating those that exist at five widely separated locations along the migratory pathway, responded by swimming in directions that would, in each case, help turtles remain in the gyre and advance along the migratory route. In this study, hatchlings were exposed to several additional magnetic fields that exist along or outside of the gyre's northern boundary. Hatchlings responded to fields that exist within the gyre currents by swimming in directions consistent with their migratory route at each location, whereas turtles exposed to a field that exists north of the gyre had an orientation that was statistically indistinguishable from random. These results are consistent with the hypothesis that loggerhead turtles entering the sea for the first time possess a navigational system in which a series of regional magnetic fields sequentially trigger orientation responses that help steer turtles along the migratory route. By contrast, hatchlings may fail to respond to fields that exist in locations beyond the turtles' normal geographic range.