Iowa DNR
Iowa DNR Fish Kill Database

Fish Kill Event - Unnamed Tributary to Shell Rock River

The fish kill occurred about 3.0 miles north of Clarksville in section 30, T93N, R15W and section 25 and 36, T93N, R16W.

Event ID
Date of Kill
Waterbody Type
Cause Origin
Unknown - Anthropogenic Suspected
5 (10,001 - 25,000 fish killed)
Estimated Fish Killed
Kill Length
0.91 miles
Investigation Expenses
ESD Field Office
FO 2
Fisheries Office
Manchester Trout Hatchery
Created Date
7/30/2019 3:38:20 PM
Last Update
7/30/2019 3:38:20 PM
For more information about this fish kill event, contact the Field Office or Fisheries Office listed above.
Impacted Assessment Segments
No segments listed
Lat/Long uses WGS84 datum
Onsite Comments

Unconfirmed at the time of investigation. Suspected to be pesticide.

The kill was extensive in a relatively small length of stream and this observation is consistent with pesticide related kills previously investigated. Water was clear and near base flows at the time of assessment. The kill included extensive numbers of crayfish, damselfly larvae, earthworms, and adult damselflies that were not quantified. At least two dead field mice were also noted in the kill area that may have or may not have been associated with the fish kill. Fish had been dead for several days prior to the investigation and species identifications were not possible for some fish carcasses.

We identified the following eight species in the kill extent: Black Bullhead, Brook Stickleback, Central Stoneroller, Creek Chub, Green Sunfish, Southern Redbelly Dace, Western Blacknose Dace, and White Sucker. In cases where species could not be determined the value of individuals was set at $0.07, or the lowest valuation of fish provided for this region in AFS Special Publication 30.

The fish kill site was determined to be incompletely accessible given terrestrial vegetation at the location and extent of the location. The stream was completely covered by overhanging terrestrial vegetation in some areas but maintained perceptible flow in the kill area. The stream was dewatered (i.e., a losing stream segment of an intermittent stream) downstream of the kill area.