• Dale Bowman

Ice & fish kills: Again


I have not heard about as many fish kills this winter, in part because the worst of winter did not arrive until the very end of January. Though once it arrived, it lasted well into March.

And I suspect that many of the lakes and ponds ripe for winter fish kills had them at a severe level after last winter, the historic winter of 2013-14.

But particularly in the snow belt areas and other areas of northern Indiana and Illinois, this winter will again produce winter kills on some lakes and ponds, such as the scene below which I found this week a year ago when I was out with my kids.


The Indiana DNR brought out a press release/info sheet earlier this week after the first reports of winter kills started coming in.

I was particularly caught by this sentence: ``Drilling holes in ice does not prevent a fish kill.''

I know a lot of people who think that is one way to avoid fish kills.

Here is the general word, recommendations and contact info from the Indiana DNR:

Spring thaw could expose winter fish kills on small lakes, ponds

Owners of shallow ponds and lakes, especially in northern Indiana, should watch for fish kills this spring.

Because ice cover measured 20 inches thick on some northern waters, Indiana fisheries biologists anticipate receiving fish kill reports once the bodies of water thaw.

Shallow, weedy ponds are susceptible to winter kills. The most common cause of fish kills in Indiana ponds is suffocation due to the lack of oxygen.

Aquatic plants can produce oxygen only when sunlight is available. While some sunlight can penetrate clear ice, snow and thick ice can often block sunlight, resulting in dangerously low oxygen levels. Then, as aquatic plants naturally die during winter, plant decomposition consumes oxygen that fish and other aquatic life need. Once a winter kill begins, little can be done to stop it.

Pond owners who experience a fish kill or need advice on other pond-related issues can refer to Indiana’s Pond Management Booklet at

Pond owners can try to reduce the likelihood of a winter kill by installing an aeration system and removing snow from the ice when safe. Building ponds with depths greater than 10 feet also reduces the likelihood of a fish kill.

Drilling holes in ice does not prevent a fish kill.

Biologists do not expect significant fish kills at deep natural lakes and man-made reservoirs. The exception could be gizzard shad, a species that is vulnerable to prolonged cold weather. But because shad can diminish a lake’s panfish population, a shad kill may improve fishing.

On March 23, Tom Bacula, District 1 fisheries biologist, received the first report of a shad kill on Bruce Lake in Pulaski and Fulton counties.

Lake residents and anglers who observe significant fish kills on public waters should contact their district fisheries biologist. Contact information for each district is in the 2015 Fishing Regulation Guide or at

5 views0 comments