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Columnaris Disease responsible for fish die-off in Little Detroit Lake

Dead fish infected with Columnaris Disease have been washing up on the shores of Little Detroit Lake the past week, according to Jim Wolters, DNR Fisheries Manager.

He said the bacterial disease naturally occurs in fish and affects them in the spring of the year when they are undergoing some stress from spawning.

In a normal spring, the DNR sees the disease growing on fish in mid-May to mid-June. Wolter said with this year's early spring and warmer than normal water temperatures, the disease started earlier and has killed more fish than normal.

"This year it just seems a little more severe," he said.

Taking a walk along the Detroit Lakes beach, Wolter said he saw "98 to 99 percent dead sunfish, with an occasional bass, bullhead or crappie," washed up dead. The windy days have pushed the dead fish up on the beach and shoreline of Little Detroit Lake. The die-off is usually a small percentage of the fish population.

Symptoms of Columnaris Disease are discolored patches on the fish, sloughing of scales and eroded gill filaments. The DNR recommends that fish dead or dying from the disease not be consumed.

Any fish, which is normal in appearance caught from the same lake, can safely be eaten.

Wolter said his office has been receiving phone calls from the public concerned about a chemical in the lake.

Since Columnaris Disease naturally occurs in fish, there is no known cure, and the die-off is not normally the result of man's activities on the environment.