Iowa DNR investigates three fish kills in one week

Last week, the Iowa Department of Natural Resources made announcements about three fish kills in different parts of Iowa.

DNR Environmental Program Supervisor Ken Hessenius said he’s not sure if Iowa has had three similar incidents at the same time before this year. However, these types of fish kills have been common in recent years — due, at least in part, to increased aerial application of chemicals to crops.

“Aerial spraying has increased for corn and soybeans for fungal diseases and insects,” Hessenius said. Some of these chemicals are extremely toxic to aquatic life at very low levels. It is likely there are many more fish kills that go unreported in small segments of streams.”

Last week, environmental specialists and fisheries biologists from the DNR responded to a fish kill in Des Moines County in southeast Iowa.

A fish kill near the headwaters of Big Creek about a mile west of Yarmouth includes several species of dead and stressed fish including catfish, bullheads, bass, suckers and creek chubs. Dead fish were observed about a half mile downstream by late morning on Aug. 3, but it was expected the fish kill will extend further downstream.

The latest fish kill in Big Creek follows one investigated late last week and earlier this week on Cedar Fork Creek approximately five miles to the east near Mediapolis. Approximately 7.3 miles of Cedar Fork Creek was affected resulted in more than 53,500 fish being killed at a value of $8,000.

Minnows, darters, madtoms, green sunfish, gizzard shad, suckers and bullheads were most affected. Smallmouth bass was the game fish species observed most frequently.

It is believed both fish kills were caused by aerial spraying of nearby crop fields and investigation is continuing to determine the responsible parties.

DNR environmental and fisheries staff also investigated a fish kill in western Emmet County about four miles northwest of Estherville, near the Minnesota state line.

While only a few dead minnows were reported in the unnamed creek, investigators think dead fish will number in at least the hundreds.

DNR staff collected water samples for laboratory analysis, but preliminary investigation indicates aerial spraying Tuesday evening in an adjacent field may be the cause.

The DNR will continue to investigate, looking for the responsible party and seeking appropriate enforcement action.

Also last week, the DNR announced investigators looking into a Delaware County fish kill in northeast Iowa that occurred in July have been unable to identify what caused it.

DNR staff have made repeated trips to the area around Buck Creek to look for possible pollutants that may have caused the kill. However, the fish kill was reported on July 18, and DNR staff estimate the fish died at least three or four days before, making it difficult to identify a source. One of the investigators, Brian Jergenson, with the DNR’s Manchester field office, said the contaminant may have washed downstream by the time DNR was alerted to the fish kill.

“That’s why it’s so important for people to give us a call as soon as they notice dead fish or a pollutant in a stream,” he said. “The sooner they notify us, the more likely we can find and stop the contaminant.”

More than eight miles of Buck Creek were affected with 41,665 fish killed — mostly minnows, shiners, chubs and dace, but also sunfish, rock bass, stone rollers and suckers. Fish restitution value is estimated at more than $6,000.

Anyone can call 515-725-8694 anytime to report fish kills to the DNR’s 24-hour emergency response line.

Hessinus said kills can be contained — depending, of course, on how many waterways and marine life are affected by the air drift of chemicals.

“Impact for these types of fish kills is usually very localized and does not move downstream to any great extent,” Hessenius said. “The problem is exacerbated by aerial application that is not precise, allowing chemicals to drift, or failure to turn off application while crossing small bodies of water.”

Contact Jason W. Brooks at 641-792-3121 ext. 6532 or jbrooks@newtondailynews.com