SPECIALIST OFFERS SUGGESTIONS TO PREVENT WINTER FISH KILLS

Fish kills not only occur during the warmer months, but can also occur during the winter," says Brad Pobst, fisheries management specialist with the Missouri Department of Conservation.

"Many winter kills can be anticipated, and measures can be taken to prevent them," said Pobst, who added that the winter kills do not commonly occur in all ponds.

"Shallow, fertile, weedy ponds are usually susceptible for a winter fish kill," he said. "The product of oxygen depends upon sunlight reaching tiny plants (phytoplankton) in the water, which produce oxygen through photosynthesis."

He adds that sunlight will penetrate several inches of clear ice, but it takes only a small amount of snow to block nearly all the light and disrupt the photosyntheic process.

"Snow causes tiny plant and other submerged vegetation to stop releasing oxygen into the water," he said. "Without sunlight for prolonged periods of time, plants may die, and the decaying process may deplete the oxygen supply to a such a low level that the fish may die.

Pobst offers some suggestions which should reduce the chance of a winter fish kill.

Keep the ice free of snow cover, so sunlight can penetrate the ice.

Shallow ponds should be deepened to at least 8 feet deep.

Aquatic vegetation should cover only 20 to 25 percent of the surface area.

Pobst urges care in removing snow from the ice.

"Before going onto the ice, use extreme caution and check its thickness," said Pobst. "As a general rule, four inches of ice is sufficient to support an individual."

Pobst suggests making "windows" for light to enter the pond by shoveling or sweeping snow off the surface. The windows, he said, should be at least 10 square feet and the more the better.

Additional information concerning fish kills is available by calling the Missouri Department of Conservation office at Cape Girardeau, 290-5730.