2019 Fiscal Year Final Research Report
Reproductive interference between endemic Cobitis roach fishes: sympatric spawning and extinction risk triggered by changes of agricultural environments
| Project/Area Number |
17K07273
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Conservation of biological resources
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| Research Institution | The University of Shiga Prefecture |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
西田 隆義 滋賀県立大学, 環境科学部, 教授 (60208189)
中西 康介 滋賀県立大学, 環境科学部, 研究員 (90726746)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | 固有種 / 絶滅危惧種 / 保全生態学 / 生物間相互作用 / 種間求愛 |
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| Outline of Final Research Achievements |
The aims of this study were to understand the mechanism that has drove Cobitis minamorii oumiensis, an endemic roach fish, into the threat of extinction and to submit some feasible plans to conserve the species. First, we showed that the juveniles were produced less in the years when the adults of the related species, C. magnostriata, were abundant at a spawning site. Second, our molecular biological study demonstrated that the C. magnostriata males courted C. minamorii oumiensis females and they hybridized. These facts supported that the reproductive interference, interspecific sexual interaction with female reproductive cost, existed between the two related species. In final, we made some modification of the spawning environment to create some paddy field-like pools that works as C. minamorii oumiensis specific spawning sites. The modification was made prior to the spawning season of 2018 and the densities of C. minamorii oumiensis juveniles increased at newly-created pools.
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| Free Research Field |
個体群生態学
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| Academic Significance and Societal Importance of the Research Achievements |
異なる種の間での配偶（求愛や送粉）が繁殖を阻害する現象である繁殖干渉は、近年になって実証研究が増加してきたものの、実際の保全に応用された例はなかった。本研究は、琵琶湖固有な絶滅危惧種のビワコガタスジシマドジョウについて、その減少要因が繁殖干渉であることをいくつかの調査・分析から明らかにし、さらにこの知見を応用した本種の保全策を提案・実施した。繁殖干渉というメカニズムを明らかにしたことから、具体的かつ検証可能な保全策を策定することができ、現在知られる唯一の繁殖地においてその有効性を確かめることができた。
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