Pelican River's low oxygen levels blamed in fish kill near Orr
Thousands of fish, including many game fish, have died in a fish kill on the Pelican River near Orr, said Kevin Peterson, Department of Natural Resources area fisheries supervisor at International Falls.
"It was a substantial fish kill. It's an unfortunate loss of our fisheries resource," Peterson said.
The kill, probably caused by low oxygen levels in the water, occurred in an approximately 2-mile stretch of the Pelican River from the dam at St. Louis County Highway 23 and downstream past U.S. Highway 53, Peterson said. The fish kill was first reported Thursday, Peterson said. A fisheries crew visited the site on Monday and traveled the river by canoe to assess the extent of the kill.
"They saw a lot of northern pike, one smallmouth bass, lots and lots and lots of black crappies -- probably thousands from 3 inches and up,"
Peterson said. "They saw some larger bluegills up to 10 inches, lots of yellow perch and bullheads and suckers."
Tom Burri, assistant area fisheries supervisor at International Falls, was part of the crew that checked out the kill.
"Definitely, there were thousands of crappies and hundreds and hundreds of pike," Burri said.
No dead walleyes were observed, Peterson said.
While lots of anglers fish nearby Pelican Lake, fishing pressure is light on the Pelican River itself, Peterson said.
Low oxygen levels in the river probably were responsible for the kill, which is called "winterkill" by fisheries biologists, Peterson said. Last fall's low water levels, the result of a six-month drought, probably exacerbated the low oxygen levels, Peterson said. Many streams and lakes were at low levels going into the winter.
"If there's a small amount of water, it has a small amount of oxygen to sustain the fish through the winter," he said.
Another fish kill involving mostly bullheads and suckers occurred on a portion of the Rat Root River, which feeds Black Bay of Rainy Lake, Peterson said.
The kill probably happened when the river was still ice-covered, he said.
"We've been noticing it (the fish kill) for the past two weeks," said Kathie Holman of Orr.
Many of the dead fish were found frozen in the ice. Since then, the ice has gone out. Once a body of water is no longer ice-covered, its oxygen levels increase. In addition, runoff from snowmelt has brought oxygenated water into the river, he said.
Peterson said he did not investigate the incident last week when it was first reported because the spring snowmelt had begun.
"Once snowmelt begins, you've passed the point of minimum oxygen in the water," Peterson said.
He said the fishery will be affected in the short term but will recover.
"The fish that are living there are adapted to these occasional low oxygen levels," Peterson said. They're good at coming back and repopulating the system."