MINOT (AP) - A lack of oxygen in the Souris River in north central North Dakota because of low water levels is leading to dead fish, and officials say the problem might worsen.
Dead northern pike, bullheads and suckers have been found in the river in Minot.
"I'm doing a master's project on that river," said Joe Super, a physical science teacher at Minot High School. "This is a documented impairment. I'd say it's due to low dissolved oxygen."
Tests conducted by North Dakota Game and Fish Department fisheries biologist Jason Lee confirmed Super's analysis. Lee said some fish have died trying to move upstream and confronting rocks they can't climb over.
"They are just doing whatever they can to find a better place to live," Lee said. "There was a trickle of water running down and the pike were trying to run up that trickle to find someplace better. Conditions are tough."
Lee has used a meter to measure oxygen in the water.
"The dissolved oxygen levels are real low," he said. "They aren't necessarily at lethal levels yet, but they are getting pretty close. They are down to 1 to 1½ parts per million, which is borderline for fish survival."
Biologists like to see at least three parts per million of dissolved oxygen to sustain a fishery, Lee said.
The depth of the water in the Souris has been measured at about 3 feet, meaning fish have little room to live. Walleye, pike, suckers, bullheads and perch all have been observed surfacing in a small area of open water near Minot's Roosevelt Park.
"Those fish would obviously be under a tremendous amount of stress," said Fred Rykman, northwest district fisheries supervisor for Game and Fish. "That is a reflection of some overall poor water quality."
The stage was set for a winter kill last spring. The gates at Lake Darling Dam on the Souris northwest of Minot were closed last May because of low water in that reservoir. Flows in the river were reduced to a trickle by late summer. Without any fresh water moving through the Souris, the water becomes stagnant.
"I don't know what could change it for the better," Lee said. "These fish are going to be in tough shape here in a month or so with more snow and thicker ice. It'll be a hostile environment for fish."
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