FREMONT, Ind. (AP) — Hundreds of fish found dead in a northeastern Indiana lake likely died from natural events tied to recent hot weather, state wildlife officials said.

Fisheries biologists with the Indiana Department of Natural Resources visited Clear Lake on Aug. 4 after residents reported numerous dead fish in the lake near the Steuben County town of Fremont, The Journal Gazette reported.

The DNR said an estimated 500 fish were found dead, including bluegill, crappie and bass in the lake about 50 miles northeast of Fort Wayne.

The state agency said Monday that natural events likely caused the fish to die, and noted that heat, warm water and windless days can produce low levels of dissolved oxygen in lakes.

“Without dissolved oxygen, fish are unable to breathe and can die rapidly and in large numbers,” the DNR said in a news release.

DNR biologists will continue monitoring conditions at Clear Lake. While the public health threat is considered very low, the agency said people should use common sense when visiting natural waterways, especially during periods of hot weather.