稚アユの遡河回遊行動とチロキシン〔英文〕

概要

論文の詳細を見る
The objective of this study is to determine the relationship between plasma thyroxine (T4) andthe upstream migratory behavior in the juvenile ayu Plecoglossus altivelis an amphidromous salmo-noidei fish. Each group showed a great variation of T4 level: i. e. landlocked population 15. 9, amphidro-moos population 10. 4, hatchery-reared fish A 5.6, B 12.2 and C 6.4ng/ml. When they were released in the River Tsubusa, Oita Prefecture, the fish group with the higher T4 level showed the stronger tendency to migrate upstream. Similar result was confirmed in a mark-recapture experiment in an artificial river (length 250m, width 1m, depth 0.3-0.7m, velocity 0.3-0.8m/s). T4 concentration of fish swimming upstream in the artificial river was 1.3-4.0 times higher in every group than that of each counterpart going downstream. Body size, however, was not a sub-stantial factor to determine the behavior of swimming upstream or downstream. These results de-monstrated a significant positive correlation between plasma T4 and the upstream migratory be-havior, suggesting that T4 played some role in the upstream migration of the ayu.
日本水産學會の論文