| Project/Area Number |
10041178
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
生態
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| Research Institution | Osaka City University |
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Principal Investigator |
KOHDA Masanori Osaka City University, Faculty of Science, Professor, 理学部, 教授 (70192052)
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| Co-Investigator(Kenkyū-buntansha) |
HORI Michio Kyoto University, Faculty of Science, Professor, 大学院・理学研究科, 教授 (40112552)
KANDA Takeshi Miyazaki University, Faculty of Agriculture, Associate Professor (80183292)
NAKAJIMA Yasuhiro Miyagi University, School of Project Design, Professor (50295383)
ROSSITER Andrew Biwako Museum, Researcher
OIKAWA Shin Kyushu University, Faculty of Agriculture, Reseracher (10175234)
KARINO Kennji Tokyo Gakugei University, Faculty of Education, Lecturer (40293005)
ロシター アントリュー ビフ湖博物館, 主任研究員
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥17,800,000 (Direct Cost: ¥17,800,000)
Fiscal Year 2000: ¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1999: ¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1998: ¥7,900,000 (Direct Cost: ¥7,900,000)
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| Keywords | Bio-diversity, radiation / Fish community / Laterality / Cichlids / Adaptive / Competition, Reproduction / Mutualism / Field experiments / Morphology / Reproduction / 群集構造 / 種間競争 / 繁殖生態 / 性淘汰 / 種分化 / 地理的変異 / 群集生態学 / 生理生態 / 繁殖戦術 |
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| Research Abstract |
During the project period, field research on fish communities in Lake Tanganyika has been conducted as was planned. The fish census on the permanent quadrat gave further evidence on the stability where fish fauna, fish species and even the number of each species were quite similar not only during the study period but also the previous studies. Several field experiments conducted in rocky shores indicated that artificial disturbance on local fish had weak effect on the fauna. Artificial rocky bases made in shallow sandy bottom were colonized by several cichlids that were not restricted in rocky habitat, suggesting that long sandy beaches can operate geographical barriers on the distribution of rock dwelling fishes.
Cichlids in this lake have laterality in body morph, and it is hypothesized that the frequency of laterality in fish of the same feeding groups fluctuates with 5-year cycle. The results of this project seemed to support the hypothesis, and the obtained data will indicate that prey-predator relationship will result in the fluctuation. Namely, minority advantage operate in this phenomenon : minor morph of a fish species receive less predation pressure than fish of majority morph.
Reproductive ecologies on some littoral fishes have been conducted, including cichlids and catfishes. Biparetal care in catfishes, coorepative polyandry in a cichlid, piracy mating in monogamous substrater as analternative male mating tactic, have been revealed.
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