| Project/Area Number |
14580557
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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 |
Environmental dynamic analysis
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| Research Institution | National Institute of Advanced Industrial Science and Technology (AIST) |
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Principal Investigator |
YAMAMURO Masumi National Institute of Advanced Industrial Science and Technology (AIST), Institute for Maine Resources and Environment, Senior researcher, 海洋資源環境研究部門, 主任研究員 (80344208)
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| Co-Investigator(Kenkyū-buntansha) |
ISHITOBI Yu Shimane Prefectural Institute of Public Health and Environmental Science, Department of Aquatic Environment, Department Chief, 水環境科, 科長
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2003: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2002: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Konoisirus punkutatus / dioxin / Lake Shinji / stable isotope ratios / gonad |
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| Research Abstract |
To examine if the mass mortality of Konoisirus punkutatus at Lake Shinji in summer is caused by contamination of dioxin, we collected Konoisirus punkutatu using set nets. Dead floating fishes due to mass mortality were also collected near the east set nets in June. All the June samples were floating dead fishes. Five fishes were collected at the west set nets in December. As K. punctatus grows, it would accumulate more dioxins. However, neither body length nor total weight showed significant correlation. Some April samples and floating fishes in June showed more TEQ than the same size fishes collected in December. This may support the above hypothesis. Fishes more contaminated by dioxins may become weak to environmental stress and die off in summer. GSI expresses the degree of exhaustion due to spawning. It is calculated as follows.
GSI=Gonad weight (g)/Total weight (g)x10^2
The GSI of floating dead fishes in June were not considerably smaller than the samples in April. We additionally sampled 37 dead fishes and 35 live fishes of three years old, and compared the body length, body weight, gonad weight, GSI, and F (F=body weight/(body length)^3x10^6). Unpaired t-test suggested that they are not different between dead and live fishes. This may suggest that fishes more contaminated dioxins are easily dead after the spawning.
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