TRANSMISSION OF FRIGHT REACTION BETWEEN DIFFERENT SPECIES OF FISH

Awareness of predators in group living species can be brought about in two ways. Either an individual directly senses a predator itself or it gets indirect information by monitoring other group members which have detected a predator. In this paper, I demonstrate such information transfer between two species of fish. A mixed shoal of chub (Leuciscus cephalus) and sticklebacks (Gasterosteus aculeatus) was presented with Schreckstoff an alarm substance, wide-spread among cyprinid fishes. Sticklebacks are not sensitive to Schreckstoff and their behaviour was observed in the presence of naive and habituated chub. Naive chub responded to Schreckstoff with a strong and immediate fright reaction whereas habituated chub did not. Sticklebacks only displayed a fright reaction when associated with naive chub, which indicates that they can obtain information about a potential predator threat by monitoring the behaviour of the chub. This result suggests that shoaling with Schreckstoff-sensitive cyprinids can provide a benefit for sticklebacks.