On the Snapping of Carp, Cyprinus carpio LINNE, under Experimental Conditions

コイの”つつき”に関する実験的研究

Takahashi Masao

Murachi Shiro

Torii Hideo

広島大学水畜産学部紀要

Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University

漏斗を通して餌をとるように条件附けられたコイを用い,漏斗に対する“つつき行動”(snapping)を解発する要因を解析して,次の結果を得た.
(1) つつき行動は,漏斗の設置,水槽水(対照水)又は餌の浸漬濾液(エキス液)の流入により解発される.
(2) 漏斗の設置又は対照水の流入に対して魚が行なうつつき行動は,定った給餌時刻の50分乃至1時間40分の間に著しく活発となり,給餌後は急激に低下する.然し,摂餌してから4乃至7時間たつと,つつき行動は再び活発となる.
(3) 設置された漏斗に対するつつき行動の頻度は低く,0.06回/分/個体である.漏斗に対照水を流すとつつき行動の頻度は0.26回/分/個体高まり,エキス液を流すと,更に1.17回/分/個体高まる,
(4) つつき行動の頻度を比較することにより,魚の索餌行動を解発する刺戟信号が解析出来る.

The present study was made in order to analyse the factors which release the behavior of the carp, Cyprinus carpio LINNE, that is snapping at the tip of a glass funnel. The fish being conditioned to feed a fish meal diet introduced through the glass funnel were used.

The results can be summarized as follows;
1) The snapping behavior is released by setting of the funnel alone, as well as by the introduction of the water sampled from the aquarium (control water) or by that of the water containing some chemical components from the food (extract solution).
2) The snapping response to the fixed funnel alone or the inflow of the control water becomes most active during the period of 50 min. to 1 h. 40 min. prior to the regular feeding time, but lowers very much after the real feeding. And then they increase again after the period of 4 to 7 hours of this low activity.
3) The frequency of snapping activities is observed to be the lowest in the case of the response to the funnel alone. Those in the response to the inflow of the control water are higher by 0.26 freq/min/capita than the previous ones. And finally the frequency of the response to the inflow of the extract solution is the highest, remaining at a higher level than that of the response to the control water by 1.17 freq/min/ capita.
4) The comparison of the frequencies of the snapping activities under various experimental conditions with each other make it possible to analyse the stimulus signal releasing the food-searching behavior in the fish.

Zoology [ 480 ]

eng

広島大学水畜産学部

[ISSN] 0440-8756

[NCID] AN00213563

[NAID] 40018463809