USDA National Wildlife Research Center Symposia


Date of this Version

December 1997


In response to concerns expressed by anglers, the U.S. Fish and Wildlife Service conducted an extensive review of published studies done throughout the United States and Canada on the impacts of double-crested cormorants (Phalacrocorax auritus) on sport-fish populations in open waters. The literature review indicated that fish species valued by sport and commercial anglers make up a very small proportion of the cormorants’ diet and that these birds have a minor effect on fish populations compared to the effects of sport and commercial fishing, natural predation, and other mortality factors. The Service sent a questionnaire to State agencies, soliciting their biological information and professional opinions on the role of cormorants in regulating wild fish populations, affecting sport angler catch, and causing adverse impacts on tourism and other fish-related economies. Agency attitudes toward cormorant population control were also assessed. On the basis of literature review and the survey responses, it does not appear that a strategy of reducing double-crested cormorant populations to benefit sport fish is biologically warranted at this time.

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