Alarm reaction of three japanese cyprinid fishes, Tribolodon hakonensis, gnathopogon elongatus elongatus, and rhodeus ocellatus ocellatus.

Abstract

The alarm reactions of Japanese cyprinids, Ugui, Tribolodon hakonensis, Tamoroko, Gnarhopogon elongatus elongatus, and Tairiku-baratanago, Rhodeus ocellatus ocellatus were examined by an objective method based on an elaborate experimental design. Three species of cyprinids showed the alarm reaction to the conspecific skin extract. G. elongatus elongatus also reacted weakly to the conspecific muscle extract, whereas T. hakonensis reacted to neither muscle nor viscera extract. It was estimated by measuring the actual concentration of sample in the experimental tank that conspecific skin extract was effective at a concentration of 2.5-0.5mg (wet weight, skin)/l(water) in T. hakonensis and 0.5-0.1mg/l in G. elongatus elongatus. In interspecific test G. elongatus elongatus reacted strongly to the skin extracts of the other two species, and T. hakonensis reacted to only that of G. elongatus elongatus, and R. ocellatus ocellatus reacted to that of neither species.