This means familiar shoalmates in fathead minnows should be closely related kin and schreckstoff production should be increased when in shoals with familiar individuals.
The probability that fathead minnows escape after being captured by a northern pike significantly increases when a second pike interferes with the predation event.
Northern pike are an introduced species in many areas, so were not likely to be coevolving with fathead minnows during the evolution of the schreckstoff system.
A male fathead minnow will defend the nest site for about three to five weeks at a time, thus there is continual turnover of new males in the population.
