| Project/Area Number |
13450215
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Civil and environmental engineering
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| Research Institution | Kyushu University |
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Principal Investigator |
KUSUDA Tetsuya Kyushu, Univ., Faculty of Engng., Professor, 工学研究院, 教授 (50037967)
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| Co-Investigator(Kenkyū-buntansha) |
YAMANISHI Hiroyuki Saga Univ., Inst.Lowland Technology, Assoc.Professor, 低平地研究センター, 助教授 (20240062)
OHISHI Kyoko Kyushu, Univ., Faculty of Engng., Research Associate, 工学研究院, 助手 (20110835)
KUBA Takahiro Kyushu, Univ., Faculty of Engng., Assoc.Professor, 工学研究院, 助教授 (60284527)
IWASA You Kyushu, Univ., Faculty of Engng., Professor, 理学研究院, 教授 (70176535)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥12,500,000 (Direct Cost: ¥12,500,000)
Fiscal Year 2003: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2002: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | Aquatic Ecosystem / Kita River, Miyazaki / Deiratonotus japonicus / Life history / Simulation / endangered / ゾエア幼生 / メガローパ幼生 / Habitat Evaluation Procedure / Suitability / 生物保全 / 絶滅確率 / 北川 / 感潮河川 / 選好性 / 生息条件 / 河川改修 |
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| Research Abstract |
In order to preserve Deiratonotus japonicus, a rare species of crab in Japan, field surveys and laboratory experiments were carried out to investigate factors which influence changes in number, characteristics of the habitat, and the process of growth of Djaponicus in the Kita River, Kyushu island. Based on the results, correlations of each factor and population density of D.japonicus were analyzed.
Research results are as follows :
1)D.japonicus mainly distributes in a tidal reach from 4.8km to 6.4km from the river mouth ;
2)D.japonicus tends to decrease in number, and was in a range of 3,560,000 to 410,000 individuals at the observation period ;
3)Experimental results in a flume with sand bed shows 1.19Pa of the maximum critical tractive force for 9mm of D.japonicus in carapace ;
4)D.japonicus prefers habitat with 5 to 80mm of riverbed materials in, diameter, 20 to 25℃ of water temperature and near 0 to 10 of salinity ;
5)The number of zoeae hatched from one female crab was 710 on an average ;
6)it takes at least two months for D.japonicus' eggs to hatch ; and
7)It takes 5 days to become the second stage of zoea from the first and 9 days to grow the third from the second.
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