2022 Fiscal Year Final Research Report
Why do the Japanese sandlances burrow into the sand?
| Project/Area Number |
19K06195
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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 | Kitasato University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Keywords | イカナゴ / 水産資源 / 行動 / ストレス |
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| Outline of Final Research Achievements |
The sandlances support the food chain of coastal ecosystems and are an important fishery resource. However, their stocks have been drastically decreasing throughout Japan, and an immediate recovery is desired. Since the fish has a unique life history in which they spend most of its life in the sand, thus this study aimed to clarify the physiological and ecological significance of their sand burrowing behavior. The results showed that three types of behaviors, buried in sand, head exposure, swimming and feeding, are strictly regulated by photoperiod and circadian rhythms. In the sand, vertical migration was observed diurnally, and abnormal behaviors such as nocturnal swimming were observed in the absence of sufficient depth. It is considered essential for the conservation of the Japanese sandlances to have a substrate environment that can maintain normal behavior.
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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 |
砂に潜る魚種は多く知られているものの，イカナゴ属は特に砂に強く依存した生活史を持っている．本研究では，イカナゴ属の潜砂行動が内的および外的な要因によって厳密に制御されていることを明らかにして，魚類の行動に関する新たな知見を得た．また，これまで未知であった砂中での行動について，鉛直移動が日周的に発現することを明らかにした．イカナゴ属は瀬戸内海，伊勢三河湾，東北沿岸，北海道西部・北部などで重要な水産資源となっている．しかしいずれの漁場でも漁獲量は激減しており，数年にわたる禁漁措置も目立った効果が見られていない．本研究の成果を基に底質環境を整備していくことで，資源回復の一助となることが期待される．
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