BISMARCK, ND (KFYR) – Fisheries biologists are conducting dissolved oxygen testing on various lakes in the state to check for overwintering.
“It’s one of the things we do every winter in certain lakes, primarily in lakes where we have the opportunity to resume some kind of overwintering,” said BJ Kratz, fisheries supervisor.
Biologists also check water clarity, ice depth, water temperature, conductivity and pH levels.
Weather can certainly play a role in the condition of this fishery in North Dakota’s colder months.
“We got a lot of snow. But the important thing is that this snow fell in December. And we’ve found that the earlier in the year we get snow, the more likely we are to experience overwintering in many of our marginal waters,” Kratz said.
With the amount of snow on the ice, no oxygen is produced, Kratz said, and then the organic matter at the bottom of the lake decomposes, consuming the remaining oxygen.
“We’ve actually gone out and checked a few lakes now, and the indications are that we’re definitely going to have more than we’ve had in a couple of years,” Kratz said.
By the third week of February, biologists usually have a good idea of which lakes are in trouble.
“One of the most obvious signs that there are probably favorable conditions for wintering is the smell of hydrogen sulfide gas, like rotten eggs that people talk about. If your water smells like that, there’s a very good chance that, at least in that area, it’s not good for fishing at least,” Kratz said.
If the lake fails this winter, biologists have a plan.
“We are trying to bring back the fish in those reservoirs as soon as possible. The passage is a good example of this. Obviously, we don’t have a lot of resources to catch and ship walleye, but also, we can do some stocking adjustments by the end of February,” Kratz said.
If you suspect a lake has winter damage, report it to the Game and Fish Department at 701-328-6300.
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