Typically, the main reason for winter pond aeration is to overwinter fish. It is critical to maintain dissolved oxygen (DO) levels in the lake or pond over the winter months for fish to survive.
Some species, such as northern pike, can survive on 1 to 3 mg/L of dissolved oxygen, whereas trout species require 4-6 mg/L for optimal health.
We previously answered the question, “Why is Dissolved Oxygen Important for Ponds, Lakes, and Dugouts?“ in a blog post. Check it out and learn how dissolved oxygen levels affect your body of water.
Winter Pond Aeration and Open Water
The amount of open water is another consideration, as this is where the oxygen exchange occurs. Fish need dissolved oxygen to be healthy, and as the level of dissolved oxygen drops, so does their survival rate. Keeping a large open water area allows the toxic gasses to escape and dissolved oxygen to enter, keeping the lake well mixed, also known as destratifying.
Destratifying the water body or breaking the thermocline (see picture for reference) is critical.
The mixing releases the build-up of toxic gasses from the bottom of the lake or pond and maintains dissolved oxygen throughout the water column. Fish will naturally migrate to the aerated area, where fishing is typically better.
Although aerating during the winter benefits the body of water, it is best not to have winter pond aeration if it is unsafe to have open water.
If you choose to aerate during the winter, marking the area and putting proper signage in place to warn of the hazards is crucial. Firing up aeration early in the spring can be beneficial for the aeration benefits and removing the ice quickly, reducing the potential hazard.
Aeration during the summer months will improve water quality, reducing algae and aquatic weeds and increasing dissolved oxygen. Again, if the water is in a higher stage, it will require more dissolved oxygen to improve its health. Adding dissolved oxygen to the lake or pond using fine bubble subsurface aeration will prevent fish kills, improve water for livestock consumption, reduce odour, and decrease algae, muck, and aquatic growth.