Three fishkills were reported this week by the Department of Natural Resources. Program Supervisor Ken Hessenius says this week’s rains are probably a factor in two incidents, in Odebolt Creek near Arthur in Ida County, and in Willow Creek near Royal in Clay County.
He says streams were low with warm water and little dissolved oxygen, then in the past few days rainfall caused a lot of runoff from the feedlots. Hessenius says the packed ground of those areas often doesn’t absorb much rain, and the runoff carries manure into those already-stressed waterways. The rain was heavy in some areas, but he says that doesn’t excuse manure spills.
He says all the producers are required to control their manure effectively enough so that it doesn’t cause water problems, including fish-kills. He says they have a responsibility to “look after the streams,” and make sure the runoff from their feedlots isn’t causing a problem. Field workers have identified a couple likely sources of the manure runoff already, and will do more tests to pinpoint which caused the fishkill.
A third incident at Fisher Lake in George Wyth State Park near Waterloo, is being blamed on natural causes. A number of bass died in the oxbow of the Cedar River, and Hessenius explains it’s a scenario typical of a hot-weather die-off. It’s a very stressful time of year for fish in these shallow bodies of water, he says, as it warms up to a high temperature and their level of tolerance is small. In the spring or fall with plenty of fresh runoff he says the fish could tolerate a spell of heat or even a small dose of a pollutant without dying off.