LAKE ORION, Mich. (AP) — State officials are investigating the deaths of hundreds of adult common carp at an Oakland County lake.

Michigan’s Department of Natural Resources said between 250 and 500 of the fish have been found dead since mid-July in Lake Orion, northwest of Detroit. Area residents reported the dead fish to the state agency.

DNR fisheries division staff collected samples July 23 for analysis at the Aquatic Animal Health Laboratory at Michigan State University. Some initial findings are expected next week. A complete set of results should be available in early September.

DNR fisheries division research program manager Gary Whelan said single-species mortality events typically are caused by a specific fish pathogen that is often a virus.

Native to Europe, common carp were introduced to Michigan in the late 1870s-1880s as a food fish.