Behavior of Kokanee Oncorhynchus nerka in Lake Kuttara Observed by Echo Sounder

DOI Web Site Web Site 被引用文献1件 参考文献10件
  • Iida Koji
    Laboratory of Instrument Engineering for Fishing, Faculty of Fisheries, Hokkaido University
  • Mukai Tohru
    Laboratory of Instrument Engineering for Fishing, Faculty of Fisheries, Hokkaido University

書誌事項

タイトル別名
  • Behavior of Kokanee <i>Oncorhynchus nerka</i> in Lake Kuttara Observed by Echo Sounder
  • Behavior of Kokanee Oncorhynchus nerka

この論文をさがす

抄録

Acoustic surveys for studying the behavior of kokanee Oncorhynchus nerka in LakeKuttara, Hokkaido, have been conducted over the past ten years and several interesting results have been obtained. Kokanee were recorded on echograms as school echoes in the daytime and as numerous individual echoes in the nighttime. Their swimming layer changes seasonally in accordance with the depth change of thermocline in the lake. Kokanee also have a diurnal behavioral pattern. Namely, they form schools after sunrise and they disperse after sunset. The shifting process from individuals to schools or from schools to individuals is strongly related to illuminance, and it takes 50 minutes at sunrise and sunset for the change to occur. The swimming speed of kokanee in the daytime is faster than that in the nighttime, and the fastest speed of the day occurs at twilight. Average swimmingspeeds were estimated to be 57cm/s in the twilight, 48cm/s in the daytime and 20cm/sin the nighttime periods, respectively.

収録刊行物

被引用文献 (1)*注記

もっと見る

参考文献 (10)*注記

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ