Michigan Muskie Alliance

Virus ID'd as culprit in 2005 fish kills

A virus strain responsible for the deaths of sheephead in Lake Ontario last year was as the cause of the massive die-off of freshwater drum, or sheephead, in western Lake Erie, a state biologist said yesterday.

Jeff Tyson, fisheries biology supervisor with Ohio's Sandusky Fish Research Unit, said investigators were able to identify relatively quickly the pathogen viral hemorrhagic septicemia because of an earlier experience with a fish kill in the Bay of Quinte in Lake Ontario in spring of 2005.

Viral hemorrhagic septicemia was found in a muskellunge caught from the Michigan side of Lake St. Clair in the spring of 2005, raising the possibility the strain is spreading, said Gary Whelan, fish production manager for the Michigan Department.

"We really don't know a lot about it," Mr. Whelan said from his office in Lansing. "It's pretty new, or it may have been here but we just have not detected it before."

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DEC confirms virus as cause of fishkill in Lake Ontario, St. Lawrence River

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By WILLIAM KATES Associated Press Writer June 13, 2006

SYRACUSE, N.Y. -- Scientists say a fish virus transplanted from Europe is responsible for the deaths of thousands of round gobies in Lake Ontario and the St. Lawrence River and could threaten other species in the Great Lakes.

The discovery of viral hemorrhagic septicemia virus, or VHS, however, poses no threat to public health, said Maureen Wren, a spokeswoman with the state Department of Environmental Conservation.

DEC scientists are working closely with fish pathologists at Cornell's College of Veterinary Medicine to determine if other fish species in Lake Ontario and the St. Lawrence River are susceptible to this strain of VHS, as well as which species may act as carriers of the disease.

To date, there is no indication that the strain of VHS identified in Lake Ontario and the St. Lawrence River is affecting trout and salmon species, the region's' two largest sport species.

"We are on guarded watch," said Paul Bowser, a professor of aquatic animal medicine at Cornell who helped isolate and identify the virus.

"It's certainly an issue of concern ... This is a new pathogen to the area. The jury is out as to how significant of an impact it will have and how much damage will result in the fishery. It has the potential to be dramatic," Bowser said.

Especially, if the fish are excessively stressed this summer by warmer-than-normal or rapidly changing water temperatures, he said.

The virus was first detected in preliminary tests in May 2006 fish kill of round gobies on the St. Lawrence River. Gobies are an invasive species from the Black and Caspian Sea region, likely introduced into the Great Lakes by oceangoing ships in the mid-1990s.

It was the first time that VHS was found in fish within New York State, the DEC said.

Subsequently, the virus was found in 18 dead and dying muskellunge collected in the river. The Thousand Island's muskellunge fishery is world famous.

VHS virus is relatively common in continental Europe and Japan, where it first affected commercially grown freshwater trout in the 1930s and 1940s, Bowser said.

The virus' first appearance in the United States occurred in 1988 in Coho and Chinook salmon in the Pacific Northwest.

In 2005, VHS was associated with die-offs of freshwater drum and round gobies in the Bay of Quinte in Lake Ontario's Canadian waters, as well as muskellunge in Lake St. Clair in Michigan.

The virus causes lesions, hemorrhaging and loss of blood in infected fish.