Article by: DOUG SMITH , Star Tribune
Updated: March 23, 2014 - 12:08 AM
Photo: http://www.startribune.com/sports/outdo ... y#continue
Low oxygen levels in lakes are resulting in significant winterkill.
This year the sweet smell of spring will include the stench of rotting fish — thanks to a remarkably long, cold and snowy winter.
Some two dozen lakes in central and southern Minnesota have suffered some winterkill because of low oxygen levels. And the longer that ice and snow lingers on lakes, the more fish are likely to die.
“We know there’s significant dead fish,’’ said Dave McCormick, assistant regional fisheries manager in St. Paul. “I don’t think we’ve had this bad of a winter in 18 years.’’
And if ice and snow persist on lakes, “this could get worse,’’ he said.
Perhaps the most prominent — and surprising — lake to be affected so far is North Center near Lindstrom, where last week a patch of open water was choked with dead fish, including northerns, bass, walleyes and crappies, as well as carp and bullheads. Usually shallow lakes winterkill, but North Center is more than 40 feet deep in places and has no recent history of die-offs.
“It’s pretty shocking,’’ said Allan Nistler, 21, of Lindstrom, who fishes the lake and recently photographed the fish. Beneath the decaying rough fish on the surface were game fish, including big northerns, he said.
Other lakes where fish kills have occurred include Pelican and the north end of Maple Lake in Wright County; Little, Sunrise, Spider and north Goose lakes in Chisago County; Snail Lake in Ramsey County; Centerville Lake in Anoka County; and Long, North and South Stanchfield, Francis and Paul’s lakes in Isanti County.
Meanwhile, popular Knife Lake north of Mora in Kanabec County had low oxygen levels, so aerators have been installed.
Revealing extent of kill
DNR officials won’t know the extent of the fish kills until ice departs and they get reports of dead fish from lakeshore owners, or until they survey lakes with nets.
“As of today, we’re just preparing for the worst, and if it’s bad, we’ll be doing more fish stocking than we normally would,’’ said Jack Lauer, regional fisheries manager in New Ulm.
The brutal winter gets the blame. Fish die when oxygen levels drop too low to support them. Ice formed on lakes early and was quickly covered with snow, blocking sunlight from plants that produce oxygen. Those plants die, and the decaying matter consumes more of the limited oxygen.
If oxygen levels fall low enough, fish begin to die. Shallow lakes are most susceptible, and some suffer winterkills regularly.
Lauer said the first fish to die are game fish: walleyes, bass, panfish, perch and northern. Then rough fish such as carp, suckers and bullheads succumb.
“I’d say bullheads go last,’’ said Lauer. “If we get [dead] bullheads … we know it’s been a significant kill.’’
North Center Lake woes
That’s what officials fear happened on North Center Lake, because of the presence of dead carp and bullheads.
“We know there’s a pretty good kill going on,’’ said Roger Hugill, DNR area fisheries manager in Hinckley. “But it doesn’t mean there won’t be enough fish to re-establish the population.’’
Officials and locals were stunned.
“I’ve never seen it winterkill,’’ said Frankie Dusenka of Frankies Live Bait and Marine in Chisago City. “There’s still 36-plus inches of ice around here; it’s amazing.’’
DNR officials drilled holes around the lake and found very low oxygen levels — 1 part per million or less. Normally, the level would be 8 to 12 parts per million.
Concerned, DNR biologists then checked neighboring waters, including South Center, Chisago, Green and South Lindstrom, and found the oxygen levels were fine.
A fishing hot spot wiped out
At Pelican Lake near Albertville in Wright County — a fishing hot spot in recent years — officials in late February detected oxygen levels of less than 1 part per-million. So the DNR opened the shallow lake for 10 days to liberalized fishing with no limits. Joe Stewig, DNR area fisheries manager, said anglers took lots of fish for a few days, but then it appeared many of the fish remaining in the lake died.
“We had 33 to 35 inches of ice — I can’t remember the last time we had that much ice here,’’ Stewig said. “I think we’ll have a fair number of lakes with partial or full kills.’’
Pelican’s fish were destined to die, because the DNR plans to lower water levels to restore waterfowl habitat there. But for other lakes, including North Center, the fish loss can be significant. North Center won’t be opened to liberalized fishing. “It’s too late,’’ said Hugill. But repopulation might occur there because the lake is connected to South Center Lake.
The DNR assesses lakes with winterkill and determines whether to restock them or let natural reproduction occur. Sometimes the fish kills can help a lake by removing rough fish or reducing the number of small game fish, allowing survivors to grow larger.
Meanwhile, officials are hoping spring arrives soon, bringing oxygenated snowmelt into lakes.
“What we need is a full week of warm weather,’’ Hugill said.
When ice does leave, the DNR is expecting phone calls. Though many dead fish sink and decompose on lake bottoms, others wash ashore.
“People call when the ice goes out because you can’t miss the stench of dead, rotting fish,’’ McCormick said. “We’re figuring it’s going to be a busy spring for us.
Tough winter taking its toll on Minnesota fish
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God, help me be the man that my dog thinks that I am.
God, help me be the man that my dog thinks that I am.
Re: Tough winter taking its toll on Minnesota fish
[
b]Harsh Minnesota winter expected to claim many fish[/b]By Dave Orrick
dorrick@pioneerpress.com
Posted: 03/22/2014 01:37:46 PM CDT | Updated: about 21 hours ago
For much of Minnesota, this has been a good one -- meaning a bad one -- for winter fish kills.
An early freeze, followed by a thick and persistent blanket of sun-blocking snow, increased the odds that shallow lakes prone to winter fish kills would face the naturally occurring purge, according to state biologists.
But a "significant" kill on at least one deeper lake -- North Center Lake near Lindstrom -- suggests this could be one of the worst in decades.
"It's pretty sad," said Mike Waters, a resident of about 30 years along North Center, a 749-acre lake in Chisago County known for good fishing for bass, walleye, crappies and northern pike -- all of which might have been killed off in large numbers. "I don't know what to think because I've never seen it before."
Records from the Minnesota Department of Natural Resources list only two recorded winterkills, in the 1950s and in the 1960s. The lake has depths greater than 40 feet and is connected to South Center Lake by a navigable channel.
Shallow lakes are most prone to winterkills, a natural phenomenon in which a lack of sunlight reaching the water indirectly causes oxygen levels to plummet, suffocating fish.
To be clear, no one knows for sure how severe any winter fish kills are until the ice is out and fisheries biologists can conduct spring netting surveys. Lakes with severe kills will be stocked, per each lake's management plan.
Mid- to late winter, before the thaw, is generally the time of year when oxygen levels are lowest. That time has passed, and melting snow already is allowing oxygen levels to rise on lakes.
Winterkills can be a boon for fishing, because a blank slate of a lake can produce bumper crops of game fish, several DNR officials said. But they also know a strong kill can make for poor, or even pointless, fishing the following year.
"I'll be honest: Our guys are nervous," said Jack Lauer, regional fisheries manager for the DNR's Region 4, which encompasses the southwest part of the state. The region has numerous winterkill-prone shallow lakes.
"They will not be surprised if they get in there and find out in some of these lakes, yep, there's nothing much left," Lauer said.
Deep lakes in northern Minnesota are by and large immune to widespread winterkills, although some brook trout lakes in the Arrowhead have been known to experience them.
In much of Lauer's territory, the season was shaping up to be a kill-fest before the dead of winter. Oxygen levels were already "the worst in seven or eight years" when DNR workers took readings. However, the levels appeared to plateau, Lauer said, and much of the snow that shrouded other parts of the state either didn't fall or was blown off ice-covered lakes in the west-central region.
"We really don't know whether a lot of these lakes had kills or not," he said.
But the list of known casualties has grown. In addition to smaller lakes prone to winterkills, the list includes:
-- Albert Lea Lake in Albert Lea: Officials have turned off an aeration system designed to reduce winterkills. The thinking is this: Rather than fight fate -- the aerator was losing ground -- and risk a partial kill of all but carp and bullheads, let the kill be complete and look toward stocking in the spring.
-- Pelican Lake in Wright County: This winter, officials -- thinking that the fish population's days were numbered from low oxygen levels -- lifted nearly all manner of fishing restrictions. In fact, Pelican's days are numbered anyway; the lake is scheduled to be drained to restore it as prime duck-breeding habitat.
-- Knife Lake near Mora: In the face of a likely strong winterkill on the 1,260-acre lake, a new aeration system was activated for the first time. Officials aren't sure whether it'll be enough.
And then there's North Center, where low water levels are suspected of exacerbating the wintry conditions.
Waters said he knew things were bad when he recently was ice fishing in 12 feet of water.
"The water is clearer than it's ever been, and I could see clear to the bottom," he said. "There was a big dead sunfish laying down there and nothing else around. Then this little crappie came fluttering along and swam up my ice hole. I couldn't get it to go back down the hole. It was looking for oxygen. That's when I knew we'd be in trouble."
Dead fish started showing up March 11 at several spots on the lake where residences with geothermal heating systems pump out warm water, which melts shoreline ice. In the case of Waters' house, the discharge is at least 35 feet from the water's edge. A pool of open water formed before -- and above -- the actual lakeshore.
"To get there, those fish would have had to burrow under the ice and snow, pretty much through the sand," he said. "One day, it was just loaded with fish. A lot of suckers were dead. I must have pulled out 150 with a pitchfork, and then I saw walleye and pike. Some of the pike underneath were still alive."
The apparently desperate uphill swim for oxygenated waters led to a gory cage match of predator and prey in the tiny pool.
"All these fish were packed in there, and the pike were still trying to eat. I saw one bullhead swimming around that was bit in half," Waters said.
On another part of the lake, a mass of dead carp and bullhead -- the two species most likely to survive a winterkill -- obscured dead walleyes, largemouth bass and pike.
Two days later, technicians from the DNR measured saturated oxygen levels in five places on the lake.
"They were basically zero," said Deb Sewell, the DNR's assistant fisheries manager for Hinckley.
If indeed the kill is as complete as some fear, the DNR will respond by stocking relatively small numbers -- perhaps 100 -- prespawn adult bluegill, perch, crappies, bass and pike netted from South Center Lake in the spring. In addition, walleye fry from rearing ponds will be introduced in the spring and fingerlings in the fall. (Natural reproduction of walleyes is minimal in North Center.)
Roger Hugill, the manager of the DNR's Hinckley-based area, said he's not ready to write off the lake for this season.
"You never know," Hugill said. "It's amazing what fish can find around the edges. Oxygen levels are rarely uniform, and if there are pockets of water with more oxygen, fish can find them."
A local guru unwilling to write the lake off is Frank Dusenka, owner of Frankie's Live Bait and Marine in Chisago City. He said a commercial fisherman with sonar that can peer 900 feet had a look and saw nothing. But he's still bullish.
"A lot of lakes around here have really low oxygen right now, so the fish can seem impossible to find, but they're still there," Dusenka said. "I know how to find them."
He regularly supplies game fish, via a special license, for display tanks at the Northwest Sportshow, which runs Wednesday through March 30 at the Minneapolis Convention Center. Normally, netting for the show is easy pickings on local waters. But last week he found himself stumped on Chisago Lake.
"I told the boys, 'We're going fishing,' " Dusenka said, and he embarked on a run-and-gun hole-drilling frenzy to locate fish. He found them one day in the late afternoon. "They were just piled up there, seemed like all the fish in the lake," he said.
"I know I could go out right now to North Center, and if you give me enough time to find them, I can catch plenty of fish. They're still there."
b]Harsh Minnesota winter expected to claim many fish[/b]By Dave Orrick
dorrick@pioneerpress.com
Posted: 03/22/2014 01:37:46 PM CDT | Updated: about 21 hours ago
For much of Minnesota, this has been a good one -- meaning a bad one -- for winter fish kills.
An early freeze, followed by a thick and persistent blanket of sun-blocking snow, increased the odds that shallow lakes prone to winter fish kills would face the naturally occurring purge, according to state biologists.
But a "significant" kill on at least one deeper lake -- North Center Lake near Lindstrom -- suggests this could be one of the worst in decades.
"It's pretty sad," said Mike Waters, a resident of about 30 years along North Center, a 749-acre lake in Chisago County known for good fishing for bass, walleye, crappies and northern pike -- all of which might have been killed off in large numbers. "I don't know what to think because I've never seen it before."
Records from the Minnesota Department of Natural Resources list only two recorded winterkills, in the 1950s and in the 1960s. The lake has depths greater than 40 feet and is connected to South Center Lake by a navigable channel.
Shallow lakes are most prone to winterkills, a natural phenomenon in which a lack of sunlight reaching the water indirectly causes oxygen levels to plummet, suffocating fish.
To be clear, no one knows for sure how severe any winter fish kills are until the ice is out and fisheries biologists can conduct spring netting surveys. Lakes with severe kills will be stocked, per each lake's management plan.
Mid- to late winter, before the thaw, is generally the time of year when oxygen levels are lowest. That time has passed, and melting snow already is allowing oxygen levels to rise on lakes.
Winterkills can be a boon for fishing, because a blank slate of a lake can produce bumper crops of game fish, several DNR officials said. But they also know a strong kill can make for poor, or even pointless, fishing the following year.
"I'll be honest: Our guys are nervous," said Jack Lauer, regional fisheries manager for the DNR's Region 4, which encompasses the southwest part of the state. The region has numerous winterkill-prone shallow lakes.
"They will not be surprised if they get in there and find out in some of these lakes, yep, there's nothing much left," Lauer said.
Deep lakes in northern Minnesota are by and large immune to widespread winterkills, although some brook trout lakes in the Arrowhead have been known to experience them.
In much of Lauer's territory, the season was shaping up to be a kill-fest before the dead of winter. Oxygen levels were already "the worst in seven or eight years" when DNR workers took readings. However, the levels appeared to plateau, Lauer said, and much of the snow that shrouded other parts of the state either didn't fall or was blown off ice-covered lakes in the west-central region.
"We really don't know whether a lot of these lakes had kills or not," he said.
But the list of known casualties has grown. In addition to smaller lakes prone to winterkills, the list includes:
-- Albert Lea Lake in Albert Lea: Officials have turned off an aeration system designed to reduce winterkills. The thinking is this: Rather than fight fate -- the aerator was losing ground -- and risk a partial kill of all but carp and bullheads, let the kill be complete and look toward stocking in the spring.
-- Pelican Lake in Wright County: This winter, officials -- thinking that the fish population's days were numbered from low oxygen levels -- lifted nearly all manner of fishing restrictions. In fact, Pelican's days are numbered anyway; the lake is scheduled to be drained to restore it as prime duck-breeding habitat.
-- Knife Lake near Mora: In the face of a likely strong winterkill on the 1,260-acre lake, a new aeration system was activated for the first time. Officials aren't sure whether it'll be enough.
And then there's North Center, where low water levels are suspected of exacerbating the wintry conditions.
Waters said he knew things were bad when he recently was ice fishing in 12 feet of water.
"The water is clearer than it's ever been, and I could see clear to the bottom," he said. "There was a big dead sunfish laying down there and nothing else around. Then this little crappie came fluttering along and swam up my ice hole. I couldn't get it to go back down the hole. It was looking for oxygen. That's when I knew we'd be in trouble."
Dead fish started showing up March 11 at several spots on the lake where residences with geothermal heating systems pump out warm water, which melts shoreline ice. In the case of Waters' house, the discharge is at least 35 feet from the water's edge. A pool of open water formed before -- and above -- the actual lakeshore.
"To get there, those fish would have had to burrow under the ice and snow, pretty much through the sand," he said. "One day, it was just loaded with fish. A lot of suckers were dead. I must have pulled out 150 with a pitchfork, and then I saw walleye and pike. Some of the pike underneath were still alive."
The apparently desperate uphill swim for oxygenated waters led to a gory cage match of predator and prey in the tiny pool.
"All these fish were packed in there, and the pike were still trying to eat. I saw one bullhead swimming around that was bit in half," Waters said.
On another part of the lake, a mass of dead carp and bullhead -- the two species most likely to survive a winterkill -- obscured dead walleyes, largemouth bass and pike.
Two days later, technicians from the DNR measured saturated oxygen levels in five places on the lake.
"They were basically zero," said Deb Sewell, the DNR's assistant fisheries manager for Hinckley.
If indeed the kill is as complete as some fear, the DNR will respond by stocking relatively small numbers -- perhaps 100 -- prespawn adult bluegill, perch, crappies, bass and pike netted from South Center Lake in the spring. In addition, walleye fry from rearing ponds will be introduced in the spring and fingerlings in the fall. (Natural reproduction of walleyes is minimal in North Center.)
Roger Hugill, the manager of the DNR's Hinckley-based area, said he's not ready to write off the lake for this season.
"You never know," Hugill said. "It's amazing what fish can find around the edges. Oxygen levels are rarely uniform, and if there are pockets of water with more oxygen, fish can find them."
A local guru unwilling to write the lake off is Frank Dusenka, owner of Frankie's Live Bait and Marine in Chisago City. He said a commercial fisherman with sonar that can peer 900 feet had a look and saw nothing. But he's still bullish.
"A lot of lakes around here have really low oxygen right now, so the fish can seem impossible to find, but they're still there," Dusenka said. "I know how to find them."
He regularly supplies game fish, via a special license, for display tanks at the Northwest Sportshow, which runs Wednesday through March 30 at the Minneapolis Convention Center. Normally, netting for the show is easy pickings on local waters. But last week he found himself stumped on Chisago Lake.
"I told the boys, 'We're going fishing,' " Dusenka said, and he embarked on a run-and-gun hole-drilling frenzy to locate fish. He found them one day in the late afternoon. "They were just piled up there, seemed like all the fish in the lake," he said.
"I know I could go out right now to North Center, and if you give me enough time to find them, I can catch plenty of fish. They're still there."
.
God, help me be the man that my dog thinks that I am.
God, help me be the man that my dog thinks that I am.
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gimpfinger
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Re: Tough winter taking its toll on Minnesota fish
Been waiting for a good kill on some shallow lakes. Might be able to hunt a few again.
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Re: Tough winter taking its toll on Minnesota fish
Best thing to happen as far as ducks are concerned. Imagine how many minnow and sucker filled ponds and sloughs have been killed off.
Re: Tough winter taking its toll on Minnesota fish
Be curious to see what it does for some of these sloughs.
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