2010 Fiscal Year Final Research Report
Coconut crab resource management based on male size-dependent reproductive potentials
| Project/Area Number |
20710184
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Resource conservation science
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| Research Institution | Fisheries Research Agency |
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Principal Investigator |
佐藤 琢 Fisheries Research Agency, 西海区水産研究所石垣支所, 技術開発員 (20455504)
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| Project Period (FY) |
2008 – 2010
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| Keywords | ヤシガニ / 繁殖生態 / 資源管理 / 体サイズ依存的な繁殖能力 / 射精量 / 絶滅危惧種 / 大型雄選択的利用 / slot size limits |
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| Research Abstract |
The harvesting pattern for coconut crab resource was sex- and body size-biased, in which larger males (>40 mm thoracic length) were exclusively taken. Sex ratio was skewed significantly toward females and mean male size decreased in the harvested population. Thus, small males that are left are likely to experience more matings than in non-harvested populations. However, coconut crab male reproductive potentials (e.g. ability to mate with female and/or to fertilize female ova) are definitively body size dependent. Therefore, females would suffer from insufficient sperm supply to fertilize all their eggs and decease in probability of encountering potential mates (larger males) in the harvested population, resulting in the reproductive rate of the harvested population is likely to decrease. Therefore, we recommend male-only harvesting with slot size limits as an effective management measure for coconut crabs.
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