| Project/Area Number |
15560043
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied physics, general
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| Research Institution | Kagoshima University |
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Principal Investigator |
NISHI Takaaki Kagoshima UNIV, Faculty of Fisheries, Assistant Professor, 水産学部, 講師 (30237656)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAMURA Gunzo Kagoshima UNIV, Faculty of Fisheries, Professor, 水産学部, 教授 (30041718)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2004: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2003: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | magnetic sense / orientation / migration / eel / rock fish / mud hopper / 方位知覚 / シラスウナギ / ティラピア |
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| Research Abstract |
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
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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
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