Effects of recreational river traffic on nest defense by longear sunfish

An underwater camera system was designed to record the behavior of male nest-guarding longear sunfish (Lepomis megalotus) during periods of boating activity. Boats traveling at slow speeds near nests usually drove males from their nests, increasing the likelihood of egg predation. Boats moving at higher speeds or further from nests caused little or no displacement of males, but increased turbidity and possible success of predators. Location of a nest near cover increased the male's ability to protect his nest during repeated surface disturbances.