The history of conflict between double-crested cormorants and human interest in fisheries is long and convoluted. Overall, double-crested cormorants are not major consumers of commercial and sportfish species. However, exceptions have been recorded at specific sites with documented impacts on local fisheries. Double-crested cormorants can have a significant impact on vegetation at breeding sites through normal nesting activities. Their guano is acidic and can change soil chemistry, killing ground vegetation and irreversibly damaging nest trees. Humans should avoid direct contact with excrement from wildlife, including droppings from cormorants. The U.S. Fish and Wildlife Service (USFWS) has the primary responsibility and authority for managing migratory bird populations in the U.S. This publication will focus on the double-crested cormorant, which is the most numerous and widely dispersed of the species.