2022 Fiscal Year Final Research Report
Study on the first food of Todarodes pacificus paralarvae focus on bacterial transmission between and mother-to-paralarvae
| Project/Area Number |
20H03055
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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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 |
Jun Yamamoto 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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| Co-Investigator(Kenkyū-buntansha) |
足立 亨介 高知大学, 教育研究部自然科学系農学部門, 教授 (00399114)
柳本 卓 国立研究開発法人水産研究・教育機構, 水産資源研究所(横浜), 主任研究員 (30443386)
中屋 光裕 北海道大学, 水産科学研究院, 准教授 (80604313)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | スルメイカ / 幼生 / 初期餌量 |
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| Outline of Final Research Achievements |
Although we were unable to collect enough numbers of adult squid to spawn naturally in a large tank, we developed a method to induce spawning in a small tank. The environment with a lot of fine organic matter was not suitable for the survival of the larvae, and they did not show any behavior to forage for the fine organic matter attached to their body surface. Analysis of equilibrium stones indicated that events that may affect subsequent survival, such as trophic conversion, may occur some time after egg yolk absorption. In addition, caecilians and other organisms were detected in stomach contents collected in natural waters, but in small quantities, suggesting the need for improvements such as preservation of materials. Gram-negative bacteria that degrade candidate factors were obtained from microorganisms attached to natural squid, and these bacteria were of the same genus as those in the breeding tanks, indicating that they may be involved in mother-to-child transmission.
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| Free Research Field |
海洋生態学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究の成果により、本種の幼生は、口器が機能していない可能性が高く、さらに、微細な有機物に対して索餌行動を示さないことが明らかとなった。本種をはじめとするアカイカ科の幼生は、微細な有機物を経口で取り込む前提で仮説が立てられているが、本研究により、幼生は経口ではない別の経路で、かつ積極的な索餌行動を取らなくても栄養を獲得できる可能性が示された。この可能性は、従来の仮説とは異なり、未だに解明されていないアカイカ科幼生の初期餌料の解明に別の視点を与えるものである。また、小型水槽内で温度刺激による産卵誘発は、大きな施設を持たなくとも自然産卵による本種の受精卵を得る方法として有効であると考えられる。
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