DEC fights to control cormorant population as they eat away at vegetation and fish
Imagine stumbling upon four islands once luscious green with trees, now ravaged as if they were victims of a wild fire or the epicenter of an atomic bomb. All life is drained in regards to vegetation.
One may wonder, was it pesticides that caused this? Others may blame global warming. However, the real culprit is roaming the islands, knee-deep in waste.
The double-crested cormorant is heading the wheel of destruction on the Four Brothers Islands and other areas of Lake Champlain. The invasive species releases an acidic feces, know as guano, which is hazardous to the island’s vegetation. The guano eventually kills the island's vegetation and prevents new vegetation from growing.
Flocks of cormorants also feed on the yellow perch fish in Lake Champlain, leaving no game fish for fisherman. “They dramatically impact fishing cycles,” says Alfred Sweenor, board member and past president of Trout Unlimited, an organization dedicated to the conservation, protection, and restoration of North America’s coldwater fisheries.
“Although they don’t eat game fish like lake trout and salmon, they go after fish bait like yellow perch and young salmon,” says Sweenor. “We don’t want the cormorants affecting our prize game fish, which are a thrill to catch,” he says.
"I’ve witnessed cormorants block out the sun as they fly over."
According to the Department of Environmental Conservation (DEC), “Cormorant populations have increased dramatically over the past 30 years, and they now threaten other water bird species and impact fisheries in several areas of New York State.”
Although cormorants are native to North America, they are invasive to Lake Champlain and the Great lakes. The species was first spotted on Lake Champlain in the 1930s and did not establish a significant population until the 1980s.
As a result of the influx in the bird population, a call for the population control of cormorant birds has been instituted. A federal rule, enacted in October 2003, gives states more supremacy in controlling the double-crested cormorant population to protect natural resources, including vegetation and fish life. Methods of population control include egg-oiling, nest destruction, hazing, and direct lethal means.
Joe Racette, wildlife biologist in DEC’s Region 5, says that the last count of cormorant nests unearthed more than 20,000 active nests. “We don’t want to create the impression that we’re trying to get rid of the cormorants. We want to bring the number back to the way they were in the 1990s,” he says, adding that 500-1,000 nests would be a reasonable goal.
The DEC instituted the population control of cormorant in 2008. “We have not yet fully established control over the population,” says Racette. “However, we didn’t expect immediate results. We expect to see results in five to seven years,” he says.
Protecting the sports fish has become the primary concern in the Great Lakes area, while the protection and conservation of native birds such as gull, heron, and the common tern, which is an endangered species in Vermont, has been the focus in the Lake Champlain area.
In looking to reduce the population of cormorants, the DEC has resorted to egg oiling. The process of covering unhatched eggs with corn oil prevents necessary gasses and heat from transferring through the shell, thus preventing the embryo from developing.
Egg oiling has proved to be an effective measure against cormorants because it minimizes the population without the need for direct lethal means. It also forces the species to migrate to other breeding grounds; once Cormorants realize that their eggs aren’t hatching they migrate to find a more suitable nesting spot.
"The DEC needs to do something to bring them back in line with their habitat. If they have to shoot them, so be it."
Another tactic that has been instituted in order to level out the population of cormorants is hazing. Hazing is used to scare the birds away, forcing them to migrate elsewhere. Shell crackers are used by the DEC in their hazing attempt. Shells fired through a shot gun or pistol emit an explosive sound and a flash of light, meant to startle and scare the target.
Racette says that hazing only affects the cormorant population locally. “When Vermont was hazing, they (Cormorants) migrated to New York, because we weren’t practicing it,” he says.
Racette says that there have been no complaints or concerns from citizens in regards to egg oiling or hazing. “People are more against lethal means,” he says. Direct lethal means are strictly reserved for adult birds who are resistant to hazing. “If anyone has any comments or concerns I will be happy to speak with them,” he says.
Sweenor says that although cormorants are not technically an invasive species, as they are native to North America, the impact that they cause on the lands vegetation and the fishery is similar to an invasive species. Once cormorants begin nesting on an island, their numbers increase at an exponential rate, making the island unsuitable for other species. “I’ve witnessed cormorants block out the sun as they fly over,” he says.
Outdoor writer Dennis April describes cormorants as “fish-eating machines.” “There are too many of them,” he says. “The DEC needs to do something to bring them back in line with their habitat. If they have to shoot them, so be it.”
Trout Unlimited - National Office
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