Journal of the Graduate School of Biosphere Science, Hiroshima University Volume 47
2008-12-20 発行

耳石Sr/Ca比による広島県沼田川水系の天然遡上アユと陸封アユの判別

Discrimination of amphidromous and landlocked ayu, Plecoglossus altivelis altivelis (Teleostei: Plecoglossidae) in the Nuta River, Hiroshima Prefecture, using the otolith Sr/Ca ratio
Yamamoto, Kanako
Takayama, Sho
Shibata, Yasuhiro
Nakamura, Kazuo
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abstract
Ayu, Plecoglossus altivelis altivelis, is a commercially important species of amphidromous fish. Thus it is being targeted for stock replenishment to sustain harvest numbers. Stock identification between amphidromous and hatchery fish was conducted using the otolith Sr/Ca concentration ratio on fish taken from the Nuta River in Hiroshima Prefecture, where 170,000 hatchery ayu had been previously released. Of 30 fish sampled from the middle-reaches, 12 were identified as an amphidromous form. Of the 13 fish sampled from the Mukunashi River, a branch of the Nuta River, all were identified as landlocked fish that would have completed their life cycle between the Mukunashi River and the artificial lakes formed by the Mukunashi Dam.
description
本研究は平成19年度広島大学地域貢献研究において,東広島市沼田川漁業協同組合より課題提案された「東広島市沼田川におけるアユの資源保全と有効利用」の一環として行った。
subject
アユ
Sr/Ca比
沼田川
椋梨ダム湖
天然遡上アユ
陸封アユ
ayu
otolith Sr/Ca ratio
amphidromous form
landlocked form
Nuta River
Mukunashi River