WINTER KILL

 

winter fish kill

What is a winter fish kill & will it effect me?

The majority of winter fish kills are experienced as cold temperatures cause ponds and lake to freeze over. Low dissolved oxygen levels result from a combination of factors. The air/water interface is capped by the formation of ice limiting the exchange of oxygen at the surface. This icy cover also reduces or completely eliminates sunlight form reaching any aquatic plant life that would otherwise produce oxygen through the process of photosynthesis. With no light available, aquatic plant life will begin to respire (consume oxygen) along with fish and other aquatic life and further increase the oxygen demand. The bacterial decomposition of organic material and bottom sludge also depletes oxygen levels.

Over time, the dissolved oxygen levels eventually become too low to sustain aquatic life. This can vary widely depending upon the type of aquatic organisms living in your pond or lake. For most warm-water fish species, like bass, crappie and bluegill, minimum oxygen levels need to be about 2ppm. Trout species require higher minimum oxygen levels, typically around 4ppm. Oxygen levels below this for extended periods of time will prove to be lethal.