Different regions of the nation approach winter pond management differently. In the South, ponds are left mostly alone. In some regions, fish will continue feeding and growing well into the coldest months.
Northern ponds are totally different.
In the South, if someone says the word "ice," it's probably related to a glass of sweet tea. In the north, ice on ponds is a given.
There's rotten ice, clear ice, milky ice, candle ice...lots of different kinds. Rarely is pond ice clear.
I'll contend that one of the biggest reasons landowners in northern states don't tend to manage their ponds is because the risk of winterkill is too high.
What are some winter strategies to do your part to help ensure your pond makes it through projected tough winter months?
First, before ice forms, check for aquatic plants. Granted, your plants may become dormant, die, and sink to the bottom. Look in shallow water and see what you see. If you see thick mats of plants, rake them out. Dead plants consume oxygen as they decompose or compost. Living plants, under dark ice, consume oxygen by respiration, the opposite of photosynthesis.
Winterkill mostly happens because too much oxygen is consumed.
It also happens because of gas offput as part of the decomposition process. That's another reason to rake out aquatic plants. Extra carbon dioxide and some hydrogen sulfides are expected. When concentrations of those byproducts reach toxic levels, fish die. Those gases can reach higher levels because they are trapped under ice and can't dissipate into the atmosphere. Same with methane.
That brings us to tip number two. Be prepared to aerate, even if you have to do it temporarily. A big air stone dropped down an augured hole with high volumes of low-pressure atmospheric air can help add oxygen and regulate quantities of those "bad" gases. You may need to drill several holes around the ice to help relieve the gases.
The third tip is to check oxygen levels. If you've spent some dollars to have a good pond, it could be a good investment to buy an oxygen meter or a water testing kit to check trends of oxygen levels in your pond.
If you see trends where oxygen levels are dropping, that can trigger you to aerate, even if just enough to keep oxygen levels slightly above lower lethal.
If your pond isn't at risk for oxygen depletion or noxious gas buildup leading to winterkill, then you can be a little more aggressive with your fisheries management. Consider "chumming" with fathead minnows to boost your fish over winter. Plus, adding some minnows occasionally increases your odds of catching some good fish when ice-fishing.
Here's your bottom line...understanding how the biology of your pond influences water chemistry takes you way into the winter months. Being able to predict and be proactive as to what to expect gives a pondmeister the chance to keep a pond healthy all through stressful winter months.
Staying proactive, keeping the water healthy, and ensuring the biology isn't negatively affecting the chemistry may just be what you need to prevent that shady little concept of winterkill.
Reprinted with permission from Pond Boss Magazine
