ST. JOSEPH, Mo. (AP) – State officials say heat and drought caused the death of about 20,000 fish in a northwest Missouri lake.

The Missouri Department of Conservation says it’s investigating the fish kill at Lake Contrary in St. Joseph. The department says heat and drought caused low dissolved oxygen levels, which killed an estimated 20,000 fish, mostly invasive Asian carp.

Scott Ryan, northwest regional fisheries supervisor for the MDC, said in a release Thursday that Lake Contrary is a 215-acre shallow oxbow lake on St. Joseph’s southern side. He says fish have been gulping for air at the surface for several weeks.

© Copyright 2012 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.