Scientists - Expect Repeated Fish Kills In Great Lakes In Years Ahead

[hatrack]

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The disease is viral hemorrhagic septicemia, which destroys tissue of the vital organs, causing lethal internal bleeding. Scientists first reported it in Europe, where it has existed for years and it killed 90 percent 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,” said Paul Bowser, a professor of aquatic animal medicine at Cornell University here. “It was panic.”

Because developing a vaccination for the fish population is unfeasible, biologists there were able to slow the spread of the disease by killing four 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, Mich. Then in May, the round goby started dying in Lake Ontario. “I was very, very surprised,” said 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 Mr. LaPlante’s home, have been reported in the St. Lawrence River, Lake Erie and in the Bay of Quinte, in Canada. At Cornell’s Aquatics lab, Dr. Bowser and Dr. Geoffrey H. 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 New York, Canada and Michigan have confirmed the disease in 12 species, including small-mouth bass, walleye, bullhead, and muskellunge. “The list is growing every couple of days,” Dr. Groocock said. “Hundreds to thousands of fish are dying every week.” In July, the United States Department of Agriculture issued a notice that outlined the potential risks and impacts of the disease. Nationally, 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.

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http://www.nytimes.com/2006/08/01/nyregion/01fish.html?_r=1&oref=slogin

[mike_c]

1. this is how ecosystems crash....

Stress the habitat, then add a factor that pushes the stress past the crash point, like an invasive organism, or an exotic pathogen, or alteration of physical parameters beyond tolerance levels. The great lakes are already under immense ecological stress, suffering a invasional meltdown, etc.