Iowa DNR
Fish Kill DatabaseDB

Fish Kill Event - Spirit Lake

S end of Spirit Lake

Event ID
Date of Kill
Waterbody Type
Cause Origin
Cyanobacteria Bloom
0 (Unknown/Unspecified fish killed)
ESD Field Office
FO 3
Fisheries Office
Spirit Lake Hatchery
Created Date
3/17/2020 9:29:28 AM
Last Update
3/17/2020 9:29:28 AM
For more information about this fish kill event, contact the Field Office or Fisheries Office listed above.
Impacted Assessment Segments
Lat/Long uses WGS84 datum
Onsite Comments

Fisheries had dead fish reported this morning around 8 am on the south side of Big Spirit Lake. We just finished up investigating the shoreline. Dissolved oxygen (DO) on the south end of the lake is around 0.65 mg/L. Fish are dead and dying. At this point, most of the dead fish are young walleyes and logperch. There are large numbers of stressed fish at the surface (small perch and bluegills).The good news is that DO levels rebound by the time we get to Templar on the SW side and Sunset Park on the SE side. DO is around 9.0 mg/L on the north end of the lake.

Water color on the south end of the lake is dark brown. Color is bright green by the time you get to the north.

It looks like the microystis bloom that was occurring on the lake died on the south end and is likely the cause. The cause of the bloom can probably be traced to heavy summer rain and high external inputs of nutrient.

This is the second such kill on Spirit this summer. The other kill occurred in the same location with similar conditions on July 20th.

The Hatchery water is coming in at very low DO concentrations also and they are injecting oxygen to keep fish alive.