In the spring, it’s not unusual to see what’s called “winter fish kill.” You might see dead fish floating to the top of your favorite lake once the ice melts, and that could send anglers into a panic.
However, tests being done now should ease fishing worries come spring.
The North Dakota Game and Fish Department is visiting the state’s lakes. On Tuesday, Harmon Lake is the department’s destination, and fish experts are drilling for answers.
“Winter kills occurs when fish run out of oxygen under the ice,” explained Paul Bailey, South Central Fisheries District Supervisor. “So in a sense, as soon as these lakes ice over in the winter, the clock starts ticking and oxygen levels become depleted.”
Which is why they are testing hundreds of bodies of water in North Dakota, looking for the dissolved oxygen levels. Most fish species in the state can survive prolonged exposure to dissolved oxygen levels down to about two parts per million.
Anything below that means the fish are likely gone.
“We’ve got a good idea,” said Bailey. “There’s always a few surprises, it seems like when the ice comes off every spring, but this gives us a pretty good indicator of where we’re gonna see winter kill occurring.”
Harmon Lake passed the test Tuesday. There’s enough oxygen in the water for the fish to survive. Bailey said most of the lakes tested so far look good — with some exceptions.
“A few lakes are certainly marginal, and we have documented at least one fish kill up at Frettim Lake up in northern Kidder County,” said Bailey.
But according to Bailey, it’s better to know now than to be surprised later. That’s why they test.
In cases where a body of water has suffered a fish kill, Bailey “puts in an order, so to speak” for more fish on the menu — from the Garrison State Fish Hatchery.
“We’re trying to benefit our anglers in North Dakota as much as we can and one of the ways is recovering these fisheries from winter kill as quickly as possible,” Bailey noted.
To date, Game and Fish is about half finished with its testing. The department has yet to measure samples from the Wishek-Ashley area and the Wing-Tuttle-Robinson area as well.