As climate changes, Minnesota’s fish feel heat

  • Article by: DOUG SMITH , Star Tribune
  • Updated: June 1, 2010 - 6:30 AM

Dieoffs are striking a cold-water species key to walleyes, muskies.

BRAINERD, MINN. - This spring's summerlike weather may be embraced by Minnesotans, but it spells trouble for ciscoes, a cold-water fish that serves as food for gamefish such as walleyes, northerns, muskies and lake trout.

Large ciscoe dieoffs -- likely caused by higher water temperatures and surface runoff that robs lakes of oxygen -- have become more common in recent years, and their populations have declined sharply in some lakes, including popular Gull Lake near Brainerd.

Researcher Andy Carlson calls ciscoes the "canary in the coal mine,'' an indicator that Minnesota lakes are changing. Ciscoes -- also known as tullibees -- will be among the first fish to feel the impact if Minnesota's summer climate becomes more like that of present-day Kansas over the next 85 years, as some studies have predicted.

"They're getting squeezed,'' said Carlson, a Department of Natural Resources fisheries biologist. The trends mean dieoffs could become more common and their populations could "blink out'' in some lakes. This year already is off to an ominous start: Many northern lakes set records for early-ice out, and air temperatures already have hit 90 degrees.

Carlson and two co-workers netted the silver fish last week on Pillager Lake near Brainerd and implanted some with tiny sonar transmitters to track their movement and measure water temperature, part of a study to help determine what the future holds.

"It could affect how we manage our walleye, northern and lake trout, over the next 10 to 20 years,'' he said.

Ping, ping, ping

The research is a fascinating blend of speed-surgery, 21st-century technology, biology -- and old-fashioned fishing.

On a warm morning, Carlson and fellow DNR fisheries biologist Rod Pierce and student intern Matt Gunderson placed a 300-foot fishing net in 220-acre Pillager Lake, waited just a few minutes, and pulled in more than a dozen ciscoes, most 11/2 to 2 pounds. The lake is loaded with them.

The goal was to implant four with small cylinder-shaped transmitters weighing less than a quarter ounce. But some of the fish failed to survive the delicate procedure.

After putting the fish in a tub and rushing to shore, the crew worked fast. Ciscoes, like trout, their relatives, are more likely to succumb to human handling than walleyes or northerns. Carlson rested a fish belly-up in a V-shaped platform, and used a small battery-powered pump to squirt water over its gills while he quickly made a 1-inch incision, popped the transmitter in and closed the wound with three stitches. Then he squirted some disinfectant on it and slipped the fish back into the lake.

Total time: 2 1/2 to 3 minutes.

Pierce, clad in waders, "walked'' the recovering patients in the lake by walking in the shallows while holding onto their dorsal fins, hoping to help reorient and stimulate them. Each transmitter costs about $700, and the batteries in them function for six months.

Some of the recovering ciscoes swam off, but others went belly-up.

"I don't see these making it,'' Pierce said has he guided two fish. When he let go, each flipped sideways.

So they recruited more "volunteers" and eventually sent four fish into the lake with transmitters, joining five others implanted earlier in the spring.

The transmitters emit a "ping'' like sonar in a submarine. They identify the fish and tell researchers the depth and water temperature where it is located. Other listening devices placed in the lake pick up the data, which Carlson regularly downloads into a computer.

Ciscoes are found in about 650 northern Minnesota lakes, but their population has been trending downward since the mid-1970s, hitting a record low in 2007. That was a particularly warm year, and major dieoffs occurred on Gull and Mille Lacs lakes, among others. Carlson expects the populations have rebounded somewhat, because 2008 and 2009 were cooler years.

But 2010 doesn't look promising.

Weather is just part of the likely cause of their decline. Carlson's research shows the fish are literally being squeezed. Here's what's happening: Ciscoes prefer water no warmer than 63 degrees. (The temperature was 68 on the surface of Pillager Lake this week.)

So as the surface water warms, they go deeper. But at the same time, nutrients and materials decomposing on the lake bottom consume oxygen, creating an oxygen-depleted "dead zone'' near the bottom. With more nutrients from runoff, that area grows, too.

The ciscoes are caught in the middle. They move to the small layer of water between those extremes. At Pillager Lake, they were limited to a 3-foot zone about halfway down in 42 feet of water. "There's nowhere for them to go,'' Carlson said.

While climate change solutions are long-term, there are some things that can be done short-term.

"If we can limit some of nutrients coming in, that could help,'' Carlson said. Protecting shorelines could help, too.

For now, ciscoes in central Minnesota are at the southern edge of their range -- a range that appears to be shifting north.

"It's possible they won't survive in some lakes,'' Carlson said.

Doug Smith • 612-673-7667

  • related content

  • Video: Monitoring fish on Pillager Lake

    Monday May 31, 2010

    DNR fisheries biologists implant small transmitters in ciscoes at Pillager Lake near Brainerd. The devices allow the scientists...

  • Photo gallery: Trouble for ciscoes

    Monday May 31, 2010

    Large die-offs of fish indicate troubling changes in Minnesota lakes.

  • Researcher Andy Carlson

  • get related content delivered to your inbox

  • manage my email subscriptions

Click here to send us your hunting or fishing photos – and to see what others are showing off from around the region.

ADVERTISEMENT

Chicago 11:30 AM
Detroit
Philadelphia 3:30 PM
Dallas
Seattle 7:30 PM
San Francisco
Cleveland 11/30/14 12:00 PM
Buffalo
Washington 11/30/14 12:00 PM
Indianapolis
Tennessee 11/30/14 12:00 PM
Houston
San Diego 11/30/14 12:00 PM
Baltimore
NY Giants 11/30/14 12:00 PM
Jacksonville
Cincinnati 11/30/14 12:00 PM
Tampa Bay
Oakland 11/30/14 12:00 PM
St. Louis
New Orleans 11/30/14 12:00 PM
Pittsburgh
Carolina 11/30/14 12:00 PM
Minnesota
Arizona 11/30/14 3:05 PM
Atlanta
New England 11/30/14 3:25 PM
Green Bay
Denver 11/30/14 7:30 PM
Kansas City
Miami 12/1/14 7:30 PM
NY Jets
Golden State 111 FINAL
Orlando 96
Brooklyn 99 FINAL
Philadelphia 91
Portland 105 FINAL
Charlotte 97
Washington 87 FINAL
Cleveland 113
LA Clippers 104 FINAL
Detroit 98
New York 102 FINAL
Dallas 109
Toronto 126 FINAL
Atlanta 115
Milwaukee 103 FINAL
Minnesota 86
Sacramento 89 FINAL
Houston 102
Utah 82 FINAL
Oklahoma City 97
Indiana 100 FINAL
San Antonio 106
Denver 112 FINAL
Phoenix 120
Memphis 99 FINAL
LA Lakers 93
Winnipeg 2 FINAL
Buffalo 1
Washington 2 FINAL(OT)
NY Islanders 3
Philadelphia 2 FINAL
Detroit 5
NY Rangers 3 FINAL
Tampa Bay 4
Carolina 0 FINAL
Florida 1
Toronto 3 FINAL(OT)
Pittsburgh 4
Los Angeles 4 FINAL
Minnesota 0
Chicago 3 FINAL
Colorado 2
Calgary 2 FINAL
San Jose 0
Robert Morris 46 FINAL
Chattanooga 61
Rochester College 35 FINAL
Eastern Mich 68
Marist 68 FINAL
Fresno State 64
Butler 74 FINAL
North Carolina 66
Liberty 50 FINAL
Morgan State 51
Denver 57 FINAL
Belmont 78
American Univ 64 FINAL
Hampton 60
Sacred Heart 72 FINAL
James Madison 79
Northeastern 54 FINAL
Massachusetts 79
Samford 71 FINAL
Kennesaw St 84
ULM 48 FINAL
Coastal Carolina 61
Hawaii 75 FINAL
East Carolina 73
Missouri 74 FINAL
Chaminade 60
UCLA 65 FINAL
Oklahoma 75
North Florida 72 FINAL
Elon 65
Oral Roberts 69 FINAL
Milwaukee 66
Chicago State 61 FINAL
Western Carolina 66
Purdue 87 FINAL
BYU 85
Furman 54 FINAL
Duke 93
San Francisco 72 FINAL
Evansville 79
Wisconsin 72 FINAL
UAB 43
Davidson 95 FINAL
UCF 69
Albany 75 FINAL
Colgate 71
Longwood 66 FINAL
George Washington 91
Delaware State 76 FINAL
Iona 126
Trinity Baptist 57 FINAL
Jacksonville 69
Cleveland State 33 FINAL
Louisville 45
St Johns 70 FINAL
Minnesota 61
PSU-Harrisburg 42 FINAL
Navy 67
Richmond 72 FINAL
NC State 84
Grambling St 54 FINAL
Notre Dame 81
Georgia State 83 FINAL
Oakland 78
Campbell 64 FINAL
Ohio State 91
Goucher 43 FINAL
Towson 97
Bryant 47 FINAL
Vermont 73
Miami-Ohio 63 FINAL
Virginia Tech 78
Mount St Marys 49 FINAL
Wake Forest 83
Lafayette 60 FINAL
Yale 82
UMKC 63 FINAL
Youngstown St 66
Canisius 60 FINAL
Cornell 67
Va Military 72 FINAL
West Virginia 103
Lehigh 86 FINAL
DePaul 74
UC Riverside 62 FINAL
Loyola Marymount 66
Morehead State 77 FINAL
Marshall 68
Miss Valley St 52 FINAL
North Texas 67
UNC-Asheville 75 FINAL
South Carolina 89
Tenn Tech 65 FINAL
SE Louisiana 86
Texas Southern 59 FINAL
SMU 72
Radford 50 FINAL
TCU 74
TX-Pan American 48 FINAL
Utah 85
Wayne St-NE 69 FINAL
South Dakota 86
Kansas State 47 FINAL
Pittsburgh 70
Northern Ill 49 FINAL
Iowa 70
Fla Gulf Coast 45 FINAL
Green Bay 59
Carroll (MT) 52 FINAL
Montana 75
Florida A&M 33 FINAL
New Mexico St 78
Auburn 71 FINAL
Oregon State 69
Eastern Ky 73 FINAL
Southern Utah 64
Stetson 41 FINAL
Wyoming 65
Northern Ky 60 FINAL
Eastern Wash 81
Utah Valley U 60 FINAL
Idaho State 57
Florida 65 FINAL
Georgetown 66
Northwestern 42 FINAL
Northern Iowa 61
Georgia 76 FINAL
Gonzaga 88
Cal Poly 52 FINAL
California 72
Utah State 70 FINAL
UC Davis 77
Arizona 61 FINAL
San Diego St 59
Alabama State 68 FINAL
North Dakota 75
Portland State 63 FINAL
CS-Northridge 55
Tulsa 58 FINAL
Oklahoma State 73
Pacific 71 FINAL
Alaska-Anchorage 62
Missouri State 19 2nd Half
Colorado State 29
Ohio U 24 FINAL
Miami-Ohio 21
LSU 6:30 PM
Texas A&M
(6) TCU 6:30 PM
Texas
Northern Ill 11/28/14 10:00 AM
Western Mich
Nebraska 11/28/14 11:00 AM
Iowa
Western Ky 11/28/14 11:00 AM
(19) Marshall
UCF 11/28/14 11:00 AM
So Florida
Houston 11/28/14 11:00 AM
SMU
Akron 11/28/14 12:00 PM
Kent State
Ball State 11/28/14 12:00 PM
Bowling Green
Buffalo 11/28/14 12:00 PM
Massachusetts
Toledo 11/28/14 12:00 PM
Eastern Mich
Arkansas 11/28/14 1:30 PM
(17) Missouri
Navy 11/28/14 2:00 PM
South Alabama
(13) Arizona State 11/28/14 2:30 PM
(12) Arizona
Stanford 11/28/14 2:30 PM
(9) UCLA
(21) Colorado State 11/28/14 2:30 PM
Air Force
Virginia 11/28/14 7:00 PM
Virginia Tech
East Carolina 11/28/14 7:30 PM
Tulsa
North Texas 11/29/14 11:00 AM
TX-San Antonio
Old Dominion 11/29/14 11:00 AM
Fla Atlantic
(16) Georgia Tech 11/29/14 11:00 AM
(8) Georgia
Kentucky 11/29/14 11:00 AM
(24) Louisville
So Carolina 11/29/14 11:00 AM
(23) Clemson
West Virginia 11/29/14 11:00 AM
Iowa State
Rice 11/29/14 11:00 AM
Louisiana Tech
Michigan 11/29/14 11:00 AM
(7) Ohio State
Purdue 11/29/14 11:00 AM
Indiana
Illinois 11/29/14 11:00 AM
Northwestern
Cincinnati 11/29/14 11:00 AM
Temple
NC State 11/29/14 11:30 AM
North Carolina
Syracuse 11/29/14 11:30 AM
Boston College
Louisiana 11/29/14 11:30 AM
Troy
Utah 11/29/14 12:00 PM
Colorado
Texas State 11/29/14 1:00 PM
Georgia State
Idaho 11/29/14 1:00 PM
Appalachian St
Wyoming 11/29/14 2:00 PM
New Mexico
New Mexico St 11/29/14 2:00 PM
Arkansas State
UAB 11/29/14 2:30 PM
Southern Miss
(4) Miss State 11/29/14 2:30 PM
(18) Ole Miss
Notre Dame 11/29/14 2:30 PM
USC
(10) Michigan State 11/29/14 2:30 PM
Penn State
(22) Minnesota 11/29/14 2:30 PM
(14) Wisconsin
(5) Baylor 11/29/14 2:30 PM
Texas Tech
Florida 11/29/14 2:30 PM
(1) Florida State
Rutgers 11/29/14 2:30 PM
Maryland
San Jose St 11/29/14 2:30 PM
San Diego St
Tennessee 11/29/14 3:00 PM
Vanderbilt
Kansas 11/29/14 3:00 PM
(11) Kansas State
Connecticut 11/29/14 3:00 PM
Memphis
BYU 11/29/14 3:30 PM
California
ULM 11/29/14 5:00 PM
Ga Southern
Middle Tennessee 11/29/14 6:00 PM
Texas-El Paso
Hawaii 11/29/14 6:00 PM
Fresno State
Wake Forest 11/29/14 6:00 PM
Duke
Pittsburgh 11/29/14 6:00 PM
Miami-Florida
(15) Auburn 11/29/14 6:45 PM
(2) Alabama
(3) Oregon 11/29/14 7:00 PM
Oregon State
Utah State 11/29/14 9:15 PM
(25) Boise State
Washington 11/29/14 9:30 PM
Washington St
Nevada 11/29/14 9:30 PM
UNLV
Hamilton 11/30/14 5:00 PM
Calgary
Kennesaw St 74 FINAL
Seton Hall 77
Northern Ill 46 FINAL
Eastern Illinois 55
Illinois-Chicago 40 FINAL
Northwestern 61
UT Martin 75 FINAL
Samford 79
Niagara 63 FINAL
Binghamton 52
Radford 47 FINAL
Pittsburgh 72
East Tenn St 69 FINAL
Indiana 97
North Dakota 72 FINAL
Nebraska Omaha 52
Marshall 49 FINAL
Cornell 58
Oral Roberts 43 FINAL
Ark-Little Rock 54
LSU 0 Postponed
Texas-El Paso 0
Boise State 59 FINAL
Yale 53
Evansville 39 FINAL
(22) West Virginia 83
(4) Tennessee 63 FINAL
Chattanooga 67
Delaware State 64 FINAL
Mount St Marys 73
Bradley 74 FINAL
Columbia 81
Providence 56 FINAL
Dayton 72
Presbyterian 43 FINAL
Xavier 45
Albany 64 FINAL
Canisius 59
VA Commonwealth 48 FINAL
William & Mary 56
Alabama A&M 44 FINAL
Alabama 75
Colgate 35 FINAL
(22) Georgia 66
Memphis 75 FINAL
Southern Ill 82
Oakland 64 FINAL
(16) Michigan State 79
Utah Valley U 49 FINAL
UC Davis 59
Butler 62 FINAL
BYU 81
TX-Pan American 45 FINAL
(6) Texas 72
McNeese State 27 FINAL
(7) Texas A&M 93
Milwaukee 80 FINAL
Marquette 85
Northern Ariz 62 FINAL
TX-Arlington 80
Jackson State 70 FINAL
Chicago State 60
Indiana State 74 FINAL
South Alabama 53
Kansas State 0 Postponed
Santa Clara 0
Long Beach St 69 FINAL
Alaska-Anchorage 60
Iona 49 FINAL
Kansas 90
Fresno Pacific 60 FINAL
CS-Bakersfield 82
Connect with twitterConnect with facebookConnect with Google+Connect with PinterestConnect with PinterestConnect with RssfeedConnect with email newsletters

ADVERTISEMENT

ADVERTISEMENT

ADVERTISEMENT

ADVERTISEMENT

question of the day

Poll: Should the lake where the albino muskie was caught remain a mystery?

Weekly Question

ADVERTISEMENT

 
Close