Journal of the Graduate School of Biosphere Science, Hiroshima University Volume 54
2015-12-25 発行

広島県太田川におけるアユ親魚群の由来判別

Discrimination of stock origin of spawning population of ayu Plecoglossus altivelis altivelis at the Ota River, Hiroshima Prefecture
Koda, Kazuya
Tamamori, Chiharu
Goto, Kento
Yamamoto, Masaki
Takayama, Sho
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abstract
Stock discrimination in the spawning population of ayu, Plecoglossus altivelis altivelis in the Ota River, western Japan was conducted using number of scales above the lateral line and otolith Sr:Ca ratio. Chart pattern in otolith Sr:Ca ratio of hatchery-stocked ayu was different in amphidromous form. Based on chart pattern of otolith Sr:Ca ratio, mixing ratio of hatchery-stocked ayu to the spawning population was estimated at 28%. Number of scales above the lateral line of spawning population marked from 13 to 26 (n=173). Based on number of scales above the lateral line (hatchery-stocked ayu ≦ 17; amphidromous ≧ 18), the mixing ratio of hatchery-stocked ayu was estimated 31%. Consequently, the contribution ratio of hatchery-stocked ayu to the spawning population was around 30% at the Ota River.
subject
アユ
太田川
産卵群
耳石Sr:Ca比
Plecoglossus altivelis altivelis
Spawning population
Ota River
Otolith Sr:Ca ratio