Methods used to minimize abundance of double-crested cormorant (Phalacrocorax auritus), great blue herons (Ardea herodias), and great egrets (Arded alba) at aquaculture facilities have limited success because of the birds\u27 ability to habituate to the applied technique. The primary objectives of this study were to evaluate and quantify the effects of overhead lines on minimizing number of cormorants, egrets and herons. We measured the long-term (01 December 2000 to 14 April 2001) effectiveness of exclusion barriers positioned every 30 m at 8 aquaculture ponds in southeastern Arkansas and the post-removal of the barrier effects from 15 April to 31 May 2001. The exclusion barrier limited the number of cormorants landing on treatment ponds significantly (P \u3c 0.001, by 10-fold), had a greater effect on herons (P \u3c 0.001, by 19-fold), and completely excluded egrets. Over 200 hours of observations with the barriers installed and an additional 90 hours of post-treatment observation resulted in 23,200 cormorant observations at the site. Eight treatment ponds averaged 429 cormorant landings (1.9 birds per hour) compared to 4,240 cormorant s landings (15.6 birds per hour) on 8 control ponds. Although the physical barrier did not exclude all cormorants and other fish-eating birds from a pond, this technique offers a nonlethal, cost-efficient, easy installation and removal, and low maintenance method to minimize depredation at aquaculture ponds
