The Iowa Department of Natural Resources has identified the source of a fish kill in Dubuque County.

Lab tests confirm that ammonia in runoff from a manure storage basin at the John Hoefler Dairy in New Viennaa was responsible for the October 9th fish kill. The DNR counted 60,278 dead fish along seven miles of waterway that included Hickory Creek and Hewitt Creek and an unnamed tributary of Hickory Creek.

The majority of the fish were minnows, shiners, dace and chubs.

The DNR will seek fish restitution of $21,712 which includes a fish replacement value of $19,416 along with the cost of the investigation. The kill was first discovered at the Highway 136 bridge in Dyersville, and investigators followed the dead fish upstream where they found the manure washing into the stream.