| Project/Area Number |
21580241
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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 |
General fisheries
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| Research Institution | Fisheries Research Agency |
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Principal Investigator |
KIYOTA Masashi 独立行政法人水産総合研究センター, 国際水産資源研究所・外洋資源部, グループ長 (10371931)
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| Co-Investigator(Kenkyū-buntansha) |
OKAMURA Hiroshi 水産総合研究センター, 国際水産資源研究所・外洋資源部, 主任研究員 (40371942)
YONEZAKI Shiro 水産総合研究センター, 国際水産資源研究所・外洋資源部, 研究員 (30463102)
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| Co-Investigator(Renkei-kenkyūsha) |
MINAMI Hiroshi 水産総合研究センター, 国際水産資源研究所・熱帯性まぐろ資源部, グループ長
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| Project Period (FY) |
2009 – 2011
|
| Project Status |
Completed (Fiscal Year 2011)
|
| Budget Amount *help |
¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2011: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2010: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2009: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Keywords | 栄養段階 / 海洋生態系 / キタオットセイ / 漁業 / 高次捕食者 / 食物連鎖 / フィッシングダウン / レジームシフト / 海洋生態 / 海洋資源 / 海洋保全 / 水産学 |
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| Research Abstract |
We compiled an electric database on Japanese fisheries off Tohoku area for 1952-2006.Analysis of the data revealed historical changes in total catch and its diversity, which showed reversed patterns to each other related to the alternation of dominant fish species. Mean trophic level of the catch did not show drastic historical fall, contrary to the"Fishing down"hypothesis asserted by some environmentalists. Analyses of northern fur seal stomach content data and gonad tissue stable isotope ratios indicated long-term shifts in diet composition and trophic level of the top predator, and resultant changes in marine food web structure.
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