RISK-SENSITIVE HABITAT USE BY BROOK STICKLEBACK (CULAEA INCONSTANS) IN AREAS ASSOCIATED WITH MINNOW ALARM PHEROMONE

Brook stickleback (Culaea inconstans) share habitat and predators with cyprinid species, and they exploit the alarm pheromone of fathead min nows (Pimephales promelas) to avoid areas of high predation risk. In t his field experiment, we measured the retention and duration of area a voidance by brook stickleback from areas marked with alarm pheromone o f fathead minnows. Area avoidance was greatest during the first 2 hr a fter the source of the alarm pheromone was removed (P < 0.05), but aft er 4 hr, area use was not significantly different from premarking leve ls. This study shows that brook stickleback: (1) use the alarm pheromo ne of fathead minnows to avoid high risk areas, (2) continue to avoid locations associated with predation risk after the source of the phero mone has gone, and (3) avoid risky areas temporarily, and resume use o f risky areas after 2-4 hr. This behavioral response by stickleback to minnow alarm pheromone could serve to minimize risk of predation.