Social mechanisms enhance escape responses in shoals of rainbowfish, Melanotaenia duboulayi

Shoaling behaviour has been shown to provide many benefits to group members. In this study we examined the ability of fish shoals to escape from a novel trawl apparatus. Fish in shoals of 5 found, and escaped through, a hole in the oncoming trawl more quickly than fish in pairs. Fish in the larger shoals displayed a significant decrease in escape latencies over a series of five trawls, providing clear evidence of net avoidance learning, whereas fish in pairs showed no evidence of learning over successive runs. Observations suggested that more information on the location of the escape route was available to fish in larger shoal sizes owing to social stimulation.