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ITHACA, N.Y.—In May, scores of dead fish started washing up along the eastern shoreline of Lake Ontario.
James LaPlante, 59, first noticed them at a friend’s house. By the following week, so many carcasses had come ashore, they littered the beach near his home in Cape Vincent, where the lake enters the St. Lawrence River, about 25 kilometres south of Kingston. “There were lots,’’ he says. “When I say lots, I mean hundreds and thousands.”
The fish had fallen victim to an unknown disease. At first, residents and fishermen were not alarmed, since the victims were round gobies, a nuisance fish that consumes the eggs of more desirable catches.
But in the weeks since, LaPlante and others in the region have noticed varied species of fish dying off — not in big numbers as with the round gobies, but far more than usual. “Now, we’re seeing bass washed up, and carp,” he says. “I don’t know, but you wonder if the round gobies were the canary in the coal mine.”
Now, scientists fear so.
Round gobies were apparently the first and most vulnerable victims of a virus new to the Lake Ontario basin and the St. Lawrence River that has the potential to kill large numbers of fish, according to scientists who have investigated the deaths. Though it is not dangerous to humans, even if they eat infected fish, scientists and government officials say it could hurt the multimillion-dollar sports-fishing business and complicate trade. Experts also fear that it could spread and ultimately threaten fish populations throughout the Great Lakes.
The disease is viral hemorrhagic septicemia, which destroys the tissue of vital organs, causing lethal internal bleeding. Scientists first reported it in Europe, where it has existed for years and killed 90 per cent of the trout in some areas.
In 1988, a strain of the virus was discovered in the Pacific Northwest.
“To say it caused a major concern is a gross understatement,” says Paul Bowser, a professor of aquatic animal medicine at Cornell University in Ithaca. “It was panic.”
Because developing a vaccination for the fish population is unfeasible, biologists there were able to slow the spread of the disease in the Pacific Northwest by killing 4 million eggs and young fish in the salmon hatcheries where it was detected. Some experts were contemplating killing all marine life in any river system where the disease was found.
But there was no need. The virus proved to be a less-contagious strain than its European counterpart. Though it still exists, it has not wreaked havoc.
Last year, scientists found a strain of the virus in new bodies of water, including Lake St. Clair. Then, in May, the round goby started dying in Lake Ontario.
“I was very, very surprised,” says James Winton, director of the Western Fisheries Research Center for the United States Geological Survey in Seattle. “How it got to the Great Lakes, we don’t know.”
Scientists believe the virus mutated into a strain more contagious than the one in the Pacific Northwest.
Large fish kills, like the one near LaPlante’s home, have been reported in the St. Lawrence River, Lake Erie and in the Bay of Quinte in Ontario. At Cornell’s aquatics lab, Bowser and Dr. Geoffrey Groocock are trying to determine whether the disease is solely responsible for the kills, and how far it has spread among the fish population.
Scientists in Canada, New York and Michigan have confirmed the disease in 12 species, including smallmouth bass, walleye, bullhead and muskellunge. “The list is growing every couple of days,” Groocock says. “Hundreds to thousands of fish are dying every week.”
In July, the U.S. Department of Agriculture issued a notice that outlined the potential risks and impacts of the disease. It could result in stricter regulations on fish hatcheries, commercial fish businesses and conservation programs, the department said. The World Organization for Animal Health has recommended safeguards to prevent the spread of the disease internationally from exports of live fish.
Douglas Stang, chief of the New York State Department of Environmental Conservation, says the state is trying to learn how virulent the disease is. He says the agency is considering recommending that fishermen disinfect their boats before moving them to a new body of water to try to limit the spread of the virus. “There are very large potential ramifications,” he says.
Fish biologists expect that the Great Lakes will see large numbers of fish kills for several years — the worst occurring in the spring when weather changes stress the fish. Then, they hope, fish will gradually develop immunity, making it a less-fatal disease, like influenza in humans.
Fishing guides in the infected areas are taking a wait-and-see approach.
“My customers are concerned; they’re asking questions about it,” says Robert Dick, owner of Moby Dick Charters in Henderson Harbor, south of Cape Vincent. “But it’s a little too early. We don’t know how it’s going to play out.”
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