| Project/Area Number |
18K14516
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 40030:Aquatic bioproduction science-related
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| Research Institution | Japan Agency for Marine-Earth Science and Technology |
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Principal Investigator |
Nishikawa Haruka 国立研究開発法人海洋研究開発機構, 付加価値情報創生部門(情報エンジニアリングプログラム), 研究員 (10625396)
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2020: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2018: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
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| Keywords | マイワシ / カタクチイワシ / 耳石 / 種間競争 / 耳石解析 / 資源量変動 |
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| Outline of Final Research Achievements |
We focused on overlapping suitable nursery grounds to detect the interspecific interaction between Japanese anchovy and Japanese sardine. Suitable nursery grounds are defined as the areas where larvae grow faster. If an area with both anchovy and sardine has a specific environmental condition suitable only for sardine growth, sardine will survive there more easily than the anchovy. Suitable conditions based on growth rates obtained from a combination of otolith analyses and backward particle tracking experiments were estimated. The sizes of suitable areas were estimated considering the ideal conditions for both species. The overlap ratio for suitable anchovy nursery grounds was higher than for sardine. Thus, although anchovy and sardine larvae occur in the same area, the area is often suitable only for sardine larvae growth. These results can explain the one-way interspecific interaction from sardine to anchovy that was suggested by the recent statistical analysis.
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| Academic Significance and Societal Importance of the Research Achievements |
マイワシとカタクチイワシの資源量が逆相関となる現象は古くから知られ、両種が似た生態を持つことからも種間競争の存在は長く指摘されてきたものの、種間競争を定量的に調べることは容易ではなく、検証が難しかった。本研究では特に資源量変動への影響が大きい仔魚期の成長速度に着目し、成長に対する好適環境の重複度という指標を導入することで、種間競争の定量化に成功した。また、両種の資源量を統計的に解析した最新の研究からは、種間競争はマイワシがカタクチイワシに一方的に影響を及ぼしている可能性が示唆された。本研究の結果はこの統計解析結果に種間競争が不均衡となる具体的なメカニズムの提示による裏付けを与えるものである。
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