Distribution and Relative Impact of Avian Predators at Aquaculture Facilities in the Northeastern United States

We conducted on-site interviews at 61 randomly selected aquaculture facilities in the northeastern United States and initially censused fish-eating birds at 58 of those facilities in June 1995 to determine the distribution of avian predation problems. To examine the relative impact of these birds, we continued to study bird populations and the fish consumption rates of these birds at 30 facilities during the summer of 1995 and at 7 facilities during the spring of 1996. Approximately 80% of the fish culturists interviewed perceived bird predation to be a problem at their facility; this view was even more widely held by trout producers. Consistent with these results, 81% of the facilities surveyed during the first phase of study had at least some fish-eating birds present. When asked to list bird predators in order of importance, 76% of 49 managers responding named the great blue heron Ardea herodias as the most important predator of concern. Consistent with these findings was the presence of great...