…In each test, differently scented water was introduced to each arm of the tank, either unscented, scented with the faeces of an otter that had not eaten salmon, or scented with faeces of an otter that had eaten salmon.
The researchers looked closely at the “avoidance behaviour” of the fish by seeing how much time they spent in different parts of the tank.
The salmon seemed unperturbed by water scented with faeces from the non-salmon eating otter.
But when the water was scented by the faeces of otter which had eaten salmon the fish stayed well away, avoiding that arm of the tank 85% of the time…
Link (Via: Wales Online)