Deadly fish virus discovered in Lake Superior

A deadly fish virus has been discovered in fish from Lake Superior near Duluth.

The contagious disease, viral hemorrhagic septicemia virus, causes death in numerous fish species, but poses no threat to humans.

The virus attacks freshwater and saltwater fish and causes them to bleed to death. It already had been found in the other four Great Lakes and has been identified in 28 fish species in the Great Lakes watershed, where it has killed large numbers of walleye, muskellunge, smallmouth bass, whitefish, yellow perch and black crappies.

Dirk Peterson, acting fisheries chief for the Minnesota Department of Natural Resources, said the discovery will not change regulations in Minnesota. Anglers already are required to remove aquatic vegetation from boats and take other precautions to avoid moving invasive species from infested waters to clean waters. The DNR will continue checking for the virus in a number of lakes, he said, including private and state-owned ponds that are used to stock fish in public waters.

The virus came to the United States from Europe and was discovered in the Detroit area in 2002. The Superior discovery was made by Cornell University researchers who tested 874 fish taken last summer from seven sites in Lake Superior in collaboration with U.S. Geological Survey fisheries scientists. The disease was found in fish from St. Louis Bay and Superior Bay near Duluth, and from two sites in Michigan.

The virus is considered one of the most serious pathogens of fish worldwide “because it kills so many fish, is not treatable and infects a broad range of fish species,” said Paul Bowser, one of the researchers and a professor at Cornell’s College of Veterinary Medicine.

Peterson said he had expected the virus would eventually reach Lake Superior. He said the results remain preliminary until confirmed because scientists used a new screening tool to test the fish.

By TOM MEERSMAN
Star Tribune