Fish Kill Event - Des Moines River
Saylorville Dam Tailwaters
- Event ID
- 1059
- Date of Kill
- 7/26/2024
- Waterbody Type
- River/Stream
- Cause Origin
- Anthropogenic
- Cause
- Gas Bubble Disease
- Mode
- N/A
- Magnitude
- 0 (Unknown/Unspecified fish killed)
- Kill Length
- not enumerated
- County
- Polk
- ESD Field Office
- FO 5
- Fisheries Office
- Boone Research Station
- LongDD
- -93.68723
- LatDD
- 41.70065
- Created Date
- 8/23/2024 8:08:59 AM
- Last Update
- 8/23/2024 8:08:59 AM
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.
An individual reported dead fish in the Des Moines River (Birdland Marina and the 2nd Avenue bridge, Polk Co.) to Iowa DNR Fisheries staff on Friday July 26th, 2024. Staff confirmed the presence of recently deceased and dying Freshwater drum (8-12”), spanning from the Birdland Marina to the Saylorville Lake dam. Upon visual inspection, the drum looked heathy, and failed to exhibit the traditional signs of GBT (i.e. bubbles in fin rays, bulged eyes, etc.). Staff speculated GBT, or possibly a species-specific disease because no other species were observed during this investigation.
Iowa DNR Fisheries staff returned to the impacted stream on Monday July 29th, 2024. Unfortunately, fish were observed struggling and mortality was evident. Staff collected water quality data in the reservoir, tailwater, and 1.7 miles downstream. A collection/transportation plan was developed in collaboration with the Minnesota DNR’s Fish Health Lab. Lab staff offered to analyze recently deceased fish if Iowa DNR staff could collect fish and deliver the fish on Tuesday, July 30th.
Iowa DNR staff returned to the Saylorville Lake tailwater at 8am on Tuesday, July 30th. Additional water quality data was collected, but no struggling or dead fish were available for collection and lab analysis. The increase in discharge and river depth in the tailwater on the 29th /30th likely improved conditions enough to end the fish kill, despite documenting high gas pressures on the 30th.