"The double-crested cormorant represents one of the most ironic wildlife success stories in the past quarter century," Turner said. "In the late 1960s, many wildlife scientists thought the bird would be one of the first additions to the U.S. endangered species list." But since the early 1980s--more than a decade after DDT was banned and its effects in the environment began to fade--this species has been increasing its population by
nearly 7 percent each year. "Unfortunately," Turner adds, "this phenomenal recovery appears to be fed, literally, by a commercial fish farming industry that also has experienced a rapid growth throughout the past decade. In some locations, cormorants have benefitted from the artificial stocking of fish for recreational purposes. In one case documented in Utah, the cormorants take of stocked trout far exceeded the catch by anglers."
The cormorant is a migratory water bird that feeds almost exclusively on fish. It nests in northern states and Canada and winters throughout the South and into the Caribbean. Its migration route down the Mississippi Valley takes it through the very heart of the burgeoning new fish farming, or aquaculture, region of the United States. In Mississippi, Arkansas, and Louisiana, there are several hundred commercial catfish farms; while from Arkansas northward to Minnesota, commercial production of bait minnows and rainbow trout have become strong growth industries in recent years. Concerns in the Northeast and
Northwest focus on the potential impact of cormorant predation on out-migrating juvenile salmon.
"The cormorant situation presents some very significant challenges," according to John Nickum, the Services national aquaculture coordinator. "Its fully protected under the Migratory Bird Treaty Act, so commercial producers and anglers simply cannot take bird control measures into their own hands. If fish producers can demonstrate predation problems, our Law Enforcement branch can issue permits to kill preying birds. But our hope is that these new studies and field applications will provide an information base from which management plans can be developed. The plans can show the way to effective, low-cost, non-lethal ways to keep the cormorants away from the aquaculturists cash crop."
The first of the three efforts will provide $200,000 for the Services Northern Prairie Research Center in Jamestown, North Dakota, to look at the population dynamics and basic biology of the cormorants in the Central Flyway. The second study will be conducted by the Mississippi Cooperative Fish and Wildlife Unit, Mississippi State University, and will explore the effects of various control strategies. Lastly, the Maine Cooperative Fish and Wildlife Unit, University of Maine at Orono, will look at the effects of cormorant predation on Atlantic salmon, a species several New England states and the Service have been trying to restore as a recreational species since the 1970s.
"Fish farmers we have worked with understand how complex this situation is and have shown great patience and support while we were designing these studies," Nickum said. "What were hoping for is a win/win solution by which a migratory bird is accorded protection, while a new industry is given the opportunity to develop and grow, and certain recreational fisheries can be effectively restored.
Fish farming in the United States--especially for trout and catfish--has experienced rapid expansion since the 1970s. In 1990, the Service issued a revised and expanded National Aquaculture Policy outlining and emphasizing the agencys commitment to work with the industry to share fish culture technologies, including nutritional and disease control information.
"Good aquacultural practices can actually benefit conservation of some wild fish by alleviating harvest pressures on certain diminishing wild stocks," Nickum said. He added that the Service over the past century has helped provide a foundation for the inland freshwater fish farming industry through its fisheries research and hatchery development.
The U.S. Fish and Wildlife Service is the principal Federal agency responsible for conserving, protecting and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 93-million-acre National Wildlife Refuge System which encompasses more than 530 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 66 national fish hatcheries, 64 fishery resource offices and 78 ecological services field stations. The agency enforces Federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state fish and wildlife agencies. For further information about the programs and activities of the U.S. Fish and Wildlife Service in the Great Lakes-Big Rivers Region, please visit our home page at: http://midwest.fws.gov
