Winter kill reported on Pelican, Rat Root rivers

The dry conditions since last fall have resulted in lower than normal water levels and lower than normal oxygen levels in area lakes, rivers and streams.

“When we experience those kinds of conditions, it’s not unusual for us to see some winter kill,” said Peterson.

Thousands of fish, including some game fish, were killed in a two-mile stretch of the Pelican River from St. Louis County Highway 23 and downstream past U.S. Highway 53.

Peterson also received a report that a handful of bullheads and suckers died on the Rat Root River.

“It’s important readers understand that winter kill naturally occurs periodically in lakes and streams, especially when water levels are low or we have long cold winters with thick ice cover and deep snow,” Peterson said. Those conditions result in a low oxygen levels.

While Peterson said the winter kill is unfortunate, “in our experience the fish population recovers relatively quickly.”

Peterson said fish that live in shallow streams and lakes are “pretty well adapted to, if not surviving, recovering from occasional bouts of winter kill.”

Fish do this by moving into areas connected to water bodies where fish may have survived. “It could have been a deeper pool that provides some refuge for fish and when water levels come up they repopulate areas on their own,” he said.

Peterson said the fish killed in the Rat Root River may have sought refuge in a spring, but still didn’t survive. Peterson said no game fish were involved, as far as he knew.

“It’s one reason it’s important for us to protect flows of streams and rivers and maintain natural connections and avoid creating fish barriers as much as can, so fish can move back into areas after events like this,” he added.

When talking about improving flows and removing fish barriers, “what we’re really talking about is protecting and maintaining and providing good habitat for fish,” he said.

As an example of such efforts, he pointed to the Rat Root River habitat improvement project, a collaborative effort between the DNR and the Rainy Lake Sportfishing Club through a state grant provided to the Koochiching County Soil and Water Conservation District.

In addition, he said recovery is assisted because fish are very prolific spawners and produce more eggs than they need to maintain the population. “When this happens, the abundance of fry helps to jump start the fishery,” he said.

Spring workload

The early spring conditions experienced in Borderland allows the DNR fisheries staff to begin the spring work earlier than in other years, Peterson said.

Peterson said he anticipates a record ice-out for Rainy Lake. That date, he said, sets the pace for the spring workload.

“The Rat Root River and lake will go out even sooner than that, so we’re anticipating our activities on the Rat Root to start within the next few days,” he said Wednesday.

He called a telemetry project unique. The fisheries staff will equip 10 female walleye with radio transmitters when they enter the Rat Root River above Rat Root Lake.

“The transmitters will emit a signal we can track and we will track their movements during the spawning season,” he said. “By doing that we hope to locate preferred spawning areas within the Rat Root River and the next step will be for us to evaluate those spawning areas and see if there’s anything we can do to improve them.”

The project will support the KSWCD grant by providing information on spawning sites that can be enhanced.

Enhancement could involve removing fish barriers, many of which were removed earlier with efforts supported by the grant. Other efforts could involve removing sediment from those spawning areas or even adding spawning substrate, or rocks, in the river, he said.

“Walleye will spawn almost anywhere but eggs survive the best in clean, gravel, rock bottoms with flowing water,” he said.

The project must be the DNR’s first this spring because walleye start running up the Rat Root River as soon as the ice leaves Rat Root Lake. “We want to install the transmitters at the bottom of the river as they begin their upstream spawning run,” he said.

Almost at the same time as the transmitters are implanted, the DNR will continue what’s become an annual effort to sample walleye running up the Rat Root River and inserting tags in some of the fish.

“This will be the third year of the tagging project,” he said. “And then the information we get back from anglers and others who see those fish in the future will help us track movements of those walleye throughout Rainy Lake.”

The DNR asks that people who catch walleye with the tags to report the information on the tag to the DNR through its website or directly to local staff.

“The movements help us understand better where walleye come from that spawn in the Rat Root River and where they go after they complete spawning,” he said. “This will ultimately show the importance and value of doing everything we can to protect and enhance this run, which we can do by improving habitat. It always comes back to habitat.”

Other spring activities:

• Brook trout stocking in two streams. Peterson said the DNR a couple years ago resumed stocking brook trout in two streams, one near Cusson and the other near Big Falls. “We hope to establish a self-sustaining population in these streams,” he said. A wild strain of brook trout developed from fish in southeastern Minnesota will be stocked. Peterson encourages any trout anglers in the area to stop in and see the DNR staff for more information on the effort.

• Lake trout stocking in two lakes. Peterson said two lakes in the work area have been stocked with lake trout in an effort to produce self-sustaining populations. “We’re getting favorable reports from anglers this winter from those lakes, so it sounds like we’re having some success,” he said, adding that anglers can get more information from the DNR staff.

• Monitoring Rainy Lake for viral hemorrhagic septicemia. Rainy Lake is one of about 20 lakes the DNR regularly monitors for the virus, which results in hemorrhages and death in many species of fish. Peterson said the virus is present in Lake Superior now and has caused fish kills in the Great Lakes. “We’re concerned about this spreading into inland waters and that’s why we monitor some of more frequently visited lakes in the state,” he said.