Friday, January 29, 2010

Fish Virus Spreads To Lake Superior

Jan 27: Researchers from Cornell University are reporting that the fish virus, viral hemorrhagic septicemia virus (VHSV), that was first discovered in the Northeast in 2005 has been found for the first time in fish from Lake Superior. That means that the virus has now been documented in all of the Great Lakes. VHSV, which causes fatal anemia and hemorrhaging in many fish species, poses no threat to humans.

Paul Bowser, professor of aquatic animal medicine at Cornell's College of Veterinary Medicine and colleagues recently tested 874 fish from seven sites in Lake Superior in collaboration with the U.S. Geological Survey (USGS) Western Fisheries Research Center in Seattle. Fish from Paradise and Skanee in Michigan and St. Louis Bay and Superior Bay in Wisconsin tested positive. Some of the results have been corroborated by other laboratories; others have tests still under way. The researchers indicated that the virus, which has been identified in 28 freshwater fish species in the Great Lakes watershed, has reached epidemic proportions in the Great Lakes.

Bowser, noting that the virus has also been found in a few inland waters as well, including lakes, streams and a family-owned earthen pond said, "People come from all over the eastern United States to fish the Great Lakes. The economy of many of these areas ebbs and flows with the season and perceived value of outdoor recreational opportunities. The value of these opportunities is dependent on how successful we are at managing the health of wild fish. On a worldwide basis, VHSV is considered one of the most serious pathogens of fish, because it kills so many fish, is not treatable and infects a broad range of fish species."

The Michigan Department of Natural Resources and Environment (MDNRE) and the Wisconsin DNR issued a release which seemed to downplay the Cornell findings and said the "traces" of VHS in fish "would not lead to any immediate regulation changes for anglers or boaters." MDNRE Director Rebecca Humphries said, "We appreciate the efforts of Cornell University to help better understand this disease, but we also want to caution anglers and others who enjoy Lake Superior that this does not mean there has been a widespread outbreak of VHS in those waters. What this study does indicate is that VHS has been observed in four locations in Lake Superior, but it is not everywhere. Based on this limited finding, Michigan is not planning to make any changes in its regulations at this time."

VHSV experts Drs. Gael Kurath and James Winton from the United States Geological Survey (USGS) Western Fisheries Research Center provided independent confirmation of the Cornell findings. Winton said, “VHS is one of the most important diseases of finfish. It not only affects the health and well-being of populations of several important native fish species, but it can also impact trade, and, should it spread into the U.S. aquaculture industry, could do substantial damage as happened in Europe and parts of Japan.” USGS indicated that Experts fear the disease could potentially spread from the Great Lakes into new populations of native fish in the 31 states of the Mississippi River basin.

Access an article from Cornell University (click here). Access the release from MI & WI (click here). Access a release from USGS and link to their VHSV website (click here).