Aeration, De-icing and Avoiding Winter Fish Kills

Fall Phragmites and Cattail Control
September 3, 2019

Aeration, De-icing and Avoiding Winter Fish Kills

Evenings are feeling chilly and blackbirds are flocking up; as much as we hate to admit it: summer is on the way out and fall and winter are close on its heels.  Now is the time to start thinking about Winter Aeration and De-icing to avoid fish kills and prevent damage to seawalls, docks and other property.

Winter fish kills can be a heartbreaking experience.  Years of careful fishery management lost to a harsh winter and relentless ice cover.  Because of their relatively high oxygen demand, the biggest fish are often the first to die, so those trophy bass and those slab sunfish bite the dust first in low oxygen conditions.

The solution to winter kill is proper winter aeration and de-icing.  When a body of water freezes over, the ice forms a barrier between the water and the air; the exchange of gases with the atmosphere is halted.  This means that the water cannot uptake oxygen from the atmosphere and it also cannot release harmful gases such as carbon dioxide, methane and hydrogen sulfide that are produced by biological activity in the lake.  This is the primary cause of winter fish kills.  The longer the body of water remains ice-covered, the more likely a fish kill is to happen.

Proper Winter Aeration and De-icing open areas in the ice cover, exposing the water to the atmosphere and enabling re-oxygenation and the release of harmful gases.  By maintaining open water and constant water circulation, fish are protected from catastrophic winter-kill.

We are frequently asked if fish can be protected from winter-kill by simply boring some holes in the ice periodically.  The short answer is “no”.  The reason for the answer takes a little explaining.  First, boring holes exposes very little surface area compared to an aeration opening.  A single aeration opening that is about 20 feet in diameter would offer about 314 square feet of open surface area, so if you were using an average-size 8-inch ice auger (about 1/3 of a square foot), you would need to bore about 942 holes to make the same open surface area.  Placing that very unlikely physical endeavor aside, anyone that has ever gone ice fishing knows how briefly a hole actually stays open in cold weather before re-freezing, often a matter of just minutes, therefore you could never stop making holes in order to equal the constant opening produce by aeration.  If that still does not deter you, keep in mind that hole drilling would also do nothing to circulate the water in the pond or lake.  The frequency of this question is my only reason for presenting the actual math here.  Please believe me that hole drilling does not in any way equate to proper winter aeration.

Aeration and de-icing can also be used to protect stationary assets like docks and sea-walls by preventing ice-jacking and other ice related damage.  Placement of aerators and circulators to protect property can require some care and good planning but can save costly repairs in the spring.  Warmer water is brought to the surface near the dock or other asset by the aerator or circulator, keeping thick ice from forming.  This prevents ice from adding costly repairs to your list of spring activities.

We provide a wide selection of winter aeration and de-icing equipment and can help you select the right equipment for your particular application.  We can also install and maintain equipment for you.  Give us a call or follow this link to shop our aeration and de-icing solutions.