Fish Kill Event - Cedar River
North side of Cedar River bridge at County Hwy C33, north of Waverly.
- Event ID
- 682
- Date of Kill
- 7/12/2006
- Waterbody Type
- River/Stream
- Cause Origin
- Natural
- Cause
- Environmental
- Mode
- N/A
- Magnitude
- 1 (1 - 100 fish killed)
- Estimated Fish Killed
- 100
- Kill Length
- not enumerated
- County
- Bremer
- ESD Field Office
- FO 1
- Fisheries Office
- Manchester Trout Hatchery
- LongDD
- -92.50768
- LatDD
- 42.77384
- Created Date
- 7/18/2006 12:00:00 AM
- Last Update
- 3/18/2019 12:53:29 PM
Impacted Assessment Segments
Highlighted river segments indicate those impacted in part or whole by this fish kill event. It is not meant to represent the actual extent of the kill.
Onsite Comments
A fish kill along the Cedar River north of Waverly appears to be the result of natural causes.
A Waverly resident reported the fish kill, located just north of the bridge along county highway C33, to the DNR Wednesday morning. The dead fish were located in a backwater of the Cedar River, not the actual river itself. Fish have access to these backwater areas when river levels are high, said Bryan Hayes, the DNR fisheries biologist who investigated the fish kill.
“When the river levels went down, the backwater was isolated from the river, trapping the fish there,” Hayes said.
The backwater pool is covered with aquatic vegetation, which causes changes in the pool’s level of dissolved oxygen. Fish can become stressed when dissolved oxygen levels fall to 5 parts per million. Readings this morning were at 2 parts per million and were likely even lower earlier in the day, Hayes said.
Hayes observed about 100 dead river carp suckers, as well as some live fish, in the backwater.
“This is a pretty common occurrence when we have naturally shallow areas, like this backwater, cut off from the river,” he said.