Recapture of brackish and freshwater pond reared eels (Anguilla japonica) released into brackish water river system - Collections | Kyushu University Library

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＜departmental bulletin paper＞
Recapture of brackish and freshwater pond reared eels (Anguilla japonica) released into brackish water river system

Creator	Creator Name 松本, 斉 Matsumoto, Hitoshi マツモト, ヒトシ Affiliation Affiliation Name パルシステム生活協同組合連合会 Palsystem Consumers’ Co-operative Union
	Creator Name 秋山, 貴彦 Akiyama, Takahiko アキヤマ, タカヒコ Affiliation Affiliation Name パルシステム生活協同組合連合会 Palsystem Consumers’ Co-operative Union
	Creator Name 奥園, 久人 Okuzono, Hisato オクゾノ, ヒサト Affiliation Affiliation Name 大隅地区養まん漁業協同組合 Osumi Eel-Farming Fisheries Co-operative Association
	Author PID K001602 Creator Name 望岡, 典隆 Mochioka, Noritaka モチオカ, ノリタカ Affiliation Affiliation Name 九州大学大学院農学研究院資源生物科学部門 Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University
Language	Japanese
Publisher	九州大学大学院農学研究院
Publisher	Faculty of Agriculture, Kyushu University
Date	2021-03-01
Source Title	Science bulletin of the Faculty of Agriculture, Kyushu University
Vol	76
Issue	1
First Page	1
Last Page	6
Publication Type	Version of Record
Access Rights	open access
JaLC DOI	https://doi.org/10.15017/4363571

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PISSN	1347-0159
NCID	AA11577672
Record ID	4363571
Subject Terms	ニホンウナギ
	放流
	標識再捕獲
	畜養
	汽水
Notes	ニホンウナギの増殖を目的として実施されることの多い放流は，一般的に畜養個体の一部を用いて実施される．養鰻池の環境は野生の生息環境とは大きく異なり，畜養された個体の放流後の生存・成長や資源への寄与は十分には明らかにされていない．そこで本研究では，ニホンウナギ稚魚が接岸後初期に利用する感潮域に類似した環境条件の汽水・無加温池と一般的な養殖池の淡水・加温池で畜養した小型個体を標識放流し，放流後の生存に対する畜養環境の効果を検討した．2015 年から2017 年にかけて汽水・無加温群352 個体と淡水・加温群312 個体を標識放流し，石倉カゴや電気ショッカー等による採捕を実施したところ，汽水・無加温群の3 個体のみが再捕獲された．汽水・無加温池で畜養した個体は畜養や放流に伴う環境変化が小さいために放流後の野外環境にも適用しやすく，生存率が高かった可能性が示唆された．
Notes	Japanese eels (Anguilla japonica) cultured in commercial aquaculture ponds are often released back into Japanese rivers for the purpose of enhancing natural stocks. However, environmental conditions in commercial aquaculture ponds are different from those of natural habitats, and survival of stocked eels or their contribution to restocking efforts are not clear. In this study, we marked and released 352 eels cultured in ponds having brackish water and ambient temperature, and 312 eels cultured in conventional commercial ponds which had freshwater and were artificially heated. After we managed to only recapture 3 eels which were all previously cultured in the brackish water, non-heated ponds while no eels cultured from conventional commercial ponds were recaptured. Our result suggests that eels cultured in brackish and non-heated ponds had a higher survival rate, as these ponds initially had similar environmental conditions to those of the natural habitats of juvenile eels soon after recruitment and eels may have acclimated to natural conditions of the river much faster and with greater ease.
Created Date	2021.03.05
Modified Date	2022.11.11