SUPERIOR – At least 605 fish were killed about four miles northwest of Estherville, according to numbers released today by Iowa DNR.
The fish were all minnow size with most being brook stickleback.
“Undoubtedly we missed many fish in the count because the area was pretty inaccessible and the water was covered with duckweed making counts very difficult,” said Mike Hawkins, fisheries biologist. “Also, since the kill occurred Tuesday fish were already deteriorating and predators likely removed some too.”
DNR environmental and fisheries staff began investigating the fish kill on Wednesday, finding dead fish, crawdads and dragonfly larvae.
Environmental staff indicate aerial spraying in an adjacent field is the most likely cause, but are waiting on laboratory reports to confirm the pollutant and responsible party.
The DNR will continue to investigate and take appropriate enforcement action.