Winterkill and Other Fish Kills

Winterkill and Other Fish Kills - coming soon


Dissolved Oxygen Monitoring

The Waterville Area Fisheries office monitors dissolved oxygen levels in area lakes that have aeration systems or have a history of winterkill. Dissolved oxygen is measured from the surface where the hole is cut and down to the substrate or wherever the dissolved oxygen probe cord ends (usually 10 feet). Typically one site is tested on each lake although more may be conducted if winterkill seems imminent or readings are below 2.0 milligrams/liter or parts per million. Readings on aerated lakes are usually taken near the aerator to see if an oxygen refuge is being maintained.


Lakes are monitored periodically as the winter progresses and the results are posted as soon as possible. If you do not see a lake listed, it likely does not have a history of winterkill, is not aerated, or was deemed unnecessary for testing.


Note: These lists are informational only and should not be considered complete or "official." Winterkill can be difficult to predict and may or may not occur regardless of the following results. Unit of measure for numbers listed below is milligrams/liter or parts per million dissolved oxygen.


Dissolved Oxygen Readings in the Waterville Fisheries Area, Winter 2013-2014


MN DNR News Release (February 19, 2014): Cold Weather Causing Winterkill On Some Southern Minnesota Lakes


Updated March 7, 2014