2020 Fiscal Year Final Research Report
Development of shrimp pot with escape vent to prevent the catch of small individual of Corn-stripe shrimp in Funka-Bay, Hokkaido
| Project/Area Number |
18K05775
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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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| Review Section |
Basic Section 40030:Aquatic bioproduction science-related
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
山本 潤 北海道大学, 北方生物圏フィールド科学センター, 助教 (10292004)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | 資源保護 / 漁獲選択性 / かご漁具 / トヤマエビ |
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| Outline of Final Research Achievements |
This study investigated a method to improve selectivity of shrimp pot aiming to protect the stock of Coonstripe shrimp Pandalus hypsinotus in the Funka-Bay, Hokkaido. It was found that small individuals were particularly active at night from the water tank experiment to investigate the behavior and diurnal activity. This suggested mesh size expansion and the installation of escape gap on pot for exclusion of small shrimp would be effective.
The mesh selectivity of the pot was estimated by water tank experiments, and it was elucidated that 35 mm mesh size was suitable to protect individuals with 20 mm carapace length which correspond to the size of recruitment. Also, we confirmed that the circular escape gap with an inner diameter of 25 mm was expected to exclude the carapace length of 30 mm which correspond to the size after sexual conversion.
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| Free Research Field |
漁具漁法
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| Academic Significance and Societal Importance of the Research Achievements |
トヤマエビは，北海道近海や日本海の水深100-400m付近に生息するエビである。市場ではボタンエビの名で流通しており，広く国内で消費されているが，その漁獲量は2007年以降大きく減少している。
そこで，本研究では北海道噴火湾において本種を漁獲するかご業業を対象として，資源保護のための漁具改良法を検討し，現在使用されている網地の網目サイズ（目合）約32mmから約35mmへの拡大により甲長20mm以下の小型個体の十分な保護が可能となること，内径25mmの円形脱出口を装着することで性転換を終える甲長30 mm以下の個体を保護できることを明らかにした。この結果は，今後の本種の漁業管理に活用される。
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