Viral hemorrhagic septicemia (VHS), a virus that has caused large fish kills in the Great Lakes since 2005, may now be harmless.
VHS has been found in several spots in Lake Michigan and Lake Superior since 2009 and is blamed for large-scale fish die-offs in all of the lower Great Lakes. Now it appears the virus is benign.
VHS can cause the internal organs of fish to rupture and it was feared that it would wipe out commercial fishing. But DNR Lake Superior fisheries supervisor Peter Stevens says even though the virus is still in the lake, they haven’t found any fish kills this year from VHS.
“It does not seem to be causing massive fish kills or significant impacts to the fisheries resource, so far as we can tell,” says Stevens. “There are a number of theories. We really don't have an exact answer.”
Stevens says it appears fish have created their own VHS vaccine. “Those fish species will shed a little bit of the virus every year, which acts almost like a booster shot to the fish immune system causing these antibodies to be produced.”
Ironically, money to continue surveying fish for VHS was cut by the federal government this year, so they’re dependent on commercial and recreational anglers. But this year, there were no reports of fish killed from VHS.
“I would actually myself take that as a very good sign, even though it’s present in the system,” says Stevens. But he cautions that surveillance and quarantine of Great Lakes water and bait must continue so it doesn’t spread to inland lakes.