What's Killing Masses Of Fish In Lake St. Clair?

(WWJ) It's been an unpleasant sight this spring on Lake St. Clair -- masses of dead fish.

And residents are noticing: Gary Whelan of the DNR's fisheries division says they've had about 20 calls from local residents about the dead fish, sometimes entire schools of them, floating in the lake.

What's killing the fish? It appears to be the result of the VHS virus, which has been in the lake for more than 10 years. A perfect storm of conditions has led to mass disease.

"It will play itself out over time," Whelan said, adding "The virus, once it gets to above 60 or 65 degrees, the virus really stops replicating, so it can't cause disease anymore. Temperatures being down in the 30s and 40s and heading into the 50s now, that's prime temperature for this particular virus to replicate."

Whelan says the virus does not affect humans, so fish in the lake are still safe to eat.

The virus primarily affects gizzard shad and it's likely they died from viral hemorrhagic septicemia.  The pathogen has been present in Lake St. Clair since the early 2000s, with a common sign of the virus bloody patches on fish skin.

It's infected more than 30 species of Great Lakes fish and has been found in Lakes Superior, Huron, Erie and Ontario and a few inland lakes.  Anglers can help prevent the spread by not moving live fish between water bodies and properly disposing bait.

It's unknown how many fish have died, but Whelan said some calls have reported hundreds.