A long, harsh winter in our area could mean worse-than-usual winter fish kills on area lakes.
Fish kills aren’t only the result of contamination in the water. They also happen naturally.
Ice cover prevents wind from oxygenating the water; and the combination of ice and snow block sunlight from reaching aquatic plants which might otherwise provide oxygen in the water.
“The longer the snow and ice cover lasts, the less oxygen is in the water,” according to a report on the Iowa Environmental Focus website.
When the ice melts, the fish that died float to the surface and are blown to shore. It can look much worse than it really is, though.
“On the positive side, winter kills create a surplus of food that allows the remaining fish to experience rapid growth over the following year or two,” the Iowa Environmental Focus report said.
Farm pond owners are advised to keep water deeper than 8 feet to avoid losing the entire stock to a winter kill, according to the Iowa DNR.
If you have any doubts or concerns about a fish kill, it’s best to contact your local fisheries biologist or the DNR.
As the ice melts, dead fish were clearly visible scattered “all over the main boat launch area near the dam” at Coralville Lake on Thursday, March 13, 2014,according to KCRG.
The Iowa Department of Natural Resources activates aeration systems in some Iowa lakes to help reduce the likelihood of winter fish kills. Lakes with aeration systems include Five Island Lake in Palo Alto County, Ingham Lake in Emmet County, Center Lake and Silver Lake in Dickinson County, Clear Lake in Cerro Gordo County, Crystal Lake in Hancock County and Little Wall Lake in Hamilton County.