Magnetic sense and direction recognition of a non-migratory fishes.

磁体敏感性研究一直与动物的定位和导航有关。虽然在各种动物中都发现了磁铁矿，但关于磁铁矿参与迁徙动物的定位和导航的研究并不总是成功的。本研究利用地磁线索研究了非迁徙鱼类的磁敏性和定向能力。研究结果如下：1)用条件化和心电图法测定了鳗鱼的磁敏性，发现该方法具有较高的灵敏度和实用性。2)用该方法测定了鳗鱼和非迁徙鱼类如马口鱼、罗非鱼和黑带石斑鱼的磁敏性。磁敏性似乎被用于这些非迁徙鱼类的局部归巢。3)测定了海洋鳗鱼、河鳗和养殖鳗鱼的磁敏性。本研究的结果与过去的研究结果进行了比较，这些研究表明在美国鳗鱼…中没有磁性意义。用条件反射和心电图法检测了无渗日本鳗的磁敏性。来自淡水养殖场的五条鳗鱼通过鼻腔注射沸腾的凡士林(130-140℃)制成反渗透，这项技术被广泛用于研究鳗鱼的嗅觉和与嗅觉相关的行为。无嗅觉的鳗鱼对磁场没有反应，可能是由于注射果冻破坏了嗅器官。5)通过条件反射和心电图检查了玻璃鳗鱼阶段(新变态的幼体)的日本鳗鱼的磁敏性。在10-40次条件反射后，所有的玻璃鳗都表现出显著的条件性反应。结果表明，玻璃鳗具有很高的磁敏性，可能在生命早期就获得了地磁信息。据推测，银色相成年鳗鱼在玻璃鳗鱼阶段从开阔的海洋向大陆架和沿海水域迁徙时，通过逆转地磁方向找到了返回海洋产卵场的途径。较少

Magnet sensitivity studies have been related to orientation and navigation of animals. While the magnetite has been found in variety of animals, studies on the involvement of the magnetite in orientation and navigation of migratory animals are not always successful. This study examined the magnetosensitivity and ability of non-migratory fishes to orient by means of geomagnetic cues. The results obtained are as follows :1)Conditioning and electrocardiography method was employed to examine the magnetosensitiviy and found to be highly sensitive and useful method.2)With this method, magnetosensitivity was determined for eel as well as non-migratory fishes such as mud hopper, tilapia and darkbanded rockfish. Magnetosensitivity seems to be used in the local homing in these non-migratory fishes.3)Magnetosensitivity was determined for marine eels, river eels and farmed eels. Results of the present study were compared with those of past studies which showed no magnetic sense in the American eel … More and the European eel.4)Magnetosensitivity in anosmic Japanese eel was examined by conditioning and electrocardiography. Five eels from a freshwater farm were made anosmic by injection of boiling petroleum jelly (130-140℃) into the nasal cavity, a technique widely used in studies on olfaction and olfaction-related behavior of eels. The anosmic eels did not respond to the magnetic field, presumably due to damage of the olfactory organ from the jelly injection.5)Magnetosensitivity of the Japanese eel at the glass eel phase (newly metamorphosed juveniles) was examined by conditioning and electrocardiography. After 10-40 conditioning runs, all the glass eels exhibited a significant conditioned response. The results indicate that glass eels have high magnetosensitivity and probably acquire geomagnetic information that early in life. It is hypothesized that silver-phase adult eels find their way back to the oceanic spawning ground by reversing the geomagnetic direction that had been detected and ‘memorized' during the glass eel phase when migrating from the open ocean towards the continental shelf and coastal waters. Less