Researchers from Minnesota State University and the University of Minnesota have discovered that fishes are capable of associating sound with predation risk.
The study by Brian Wisenden, Julie Pogatshnik, Danfee Gibson, Lucia Bonacci, Adam Schumacher and Allison Willett is published in the latest issue of the journal Environmental Biology of Fishes.
The authors studied fathead minnows (Pimephales promelas) and glowlight tetras (Hemigrammus erythrozonus) by subjecting experimental fish to skin extract and sound (a 21.83Hz tone for the minnows and a 400 Hz tone for the tetras).
The skin extract of both the minnow and the tetra contained alarm substance, which is a cue chemical released upon injury to warn conspecifics of danger (i.e. a predator).
The production of alarm substance is particularly marked in the Ostariophysi (a group which includes characins, cyprinids and catfishes). Fish in the control group were subjected to sound and water only.
When the fish were retested with sound stimulus alone, the fish in the control group showed no response, but those in the experimental group exhibited reduced activity (an antipredator behaviour).
The role of sound in the natural ecology of the two fish species remains unknown, although the authors consider this phenomenon worthy of further study in fishes.
For more information, see the paper: Wisenden, BD, J Pogatshnik, D Gibson, L Bonacci, A Schumacher and A Willett (2008) Sound the alarm: learned association of predation risk with novel auditory stimuli by fathead minnows (Pimephales promelas) and glowlight tetras (Hemigrammus erythrozonus) after single simultaneous pairings with conspecific chemical alarm cues. Environmental Biology of Fishes 81, pp. 141"147.