Hundreds of fish in Lake Orion died from herpes, Michigan DNR says

Hundreds of common carp deaths in Lake Orion earlier this summer have been tied to koi herpesvirus, the Michigan Department of Natural Resources reported Friday, but they pose no threat to other species.

Gary Whelan, program director for the Michigan DNR Fisheries Division, said the common carp deaths likely came from somebody releasing a pet goldfish or koi, as koi herpesvirus affects goldfish, koi and common carp alike. 

In mid-July, residents had reported common carp deaths through the DNR’s Eyes in the Field website. The Aquatic Animal Health Laboratory at Michigan State University and DNR researchers collected samples from the lake to identify the cause. Cleyo Harris, DNR fisheries biologist, said he estimates about 300-600 common carp died in this event.

Harris said this was a “substantial mortality event for a single species.”

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The virus spreads among common carp quickly by excretion or through the epidermis and gills.

“If you’re in the neighborhood, you get infected,” Whelan said. 

Harris discouraged people from releasing live or dead fish into lakes, or transferring them from one body of water to another. Instead, Whelan said people can put fish in the freezer to euthanize them, then they can be disposed in the trash.

Go to the U.S. Fish and Wildlife Service for more information on how to safely dispose of pet goldfish, and check Michigan's bait and fish release laws.

MDNR also said freshwater fish should be fully cooked to ensure they're safe to eat. For more information, go to michigan.gov./eatsafefish.

Contact Minnah Arshad: MArshad@freepress.com and follow her on Twitter @minnaharshad. 

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