2022 Fiscal Year Final Research Report
Elucidation of frenzy and proposal of conservation plan in hawksbill and loggerhead turtles
| Project/Area Number |
19K06089
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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 39060:Conservation of biological resources-related
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| Research Institution | Kochi University |
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Principal Investigator |
Saito Tomomi 高知大学, 教育研究部総合科学系複合領域科学部門, 教授 (80632603)
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| Co-Investigator(Kenkyū-buntansha) |
河津 勲 一般財団法人沖縄美ら島財団(総合研究センター), 総合研究センター 動物研究室, 上席研究員 (50721750)
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Keywords | 絶滅危惧種 / フレンジー / ウミガメ / 孵卵条件 / 孵化幼体 / 表現型 / 生存率 |
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| Outline of Final Research Achievements |
We investigated the responses of variations of incubation temperatures based on the nesting depths and the optimal incubation conditions for various sea turtles. When eggs are incubated under 3 conditions: constant 29°), ±1°C and ±2°C diurnal fluctuations, the hatching success rates are highest at ±1°C for loggerhead turtles and at constant 29°C for hawksbill turtles. While, the rate of non-modal scute pattern (percentage of individuals with unusual arrangement of scutes on carapace) increased with the range of temperature fluctuation in hawksbill turtles. Therefore, the eggs of hawksbill turtles with shallow nesting depths are susceptible to temperature fluctuations. It has been reported that hawksbill turtles have different preferences for nesting in open areas of sandy beaches or within vegetation zones. However, it is desirable to maintain coastal vegetation, which has a high buffering effect against temperature fluctuations, on sandy beaches where hawksbill turtles nest.
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| Free Research Field |
資源保全学
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| Academic Significance and Societal Importance of the Research Achievements |
多くの卵生爬虫類で知られる、孵卵温度により誘発される孵化幼体の表現型の違い（体サイズ・形、性、運動能力等）は、適応度の違いをもたらし、個体群の存続に重要な役割を果たすと考えられている。本邦の海岸で産卵が確認されるウミガメ（アオウミガメ、アカウミガメ、タイマイ）は異なる産卵深度を選好するが、上層ほど平均温度は高く、日内変動の振幅は大きく、各種で孵卵温度への感受性が異なる可能性がある。本研究の成果は各種で孵卵温度に伴う表現型の違いを調べ、これに関わる生理学的機構を解明し、各種に最適な孵卵条件を究明する。その結果に基づき、従来の保護活動を見直して新しい指針を作り、ウミガメの資源回復に貢献できる。
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