Zebra mussels decline on Lake Mille Lacs

  • Article by: DOUG SMITH , Star Tribune
  • Updated: August 27, 2014 - 8:03 AM

After growing exponentially for several years, the zebra mussel population on Lake Mille Lacs has fallen for the second consecutive year — indicating the population might be leveling off.

“It seems to have stopped increasing and maybe is declining a bit,’’ said Tom Jones, Department of Natural Resources regional fisheries treaty coordinator.

That’s welcome news for the beleaguered lake, one of the state’s most popular fishing destinations.

Zebra mussels were discovered in the 200-square-mile lake in 2005, and their population exploded. The average density of infested areas peaked at 1,269 zebra mussels per square foot in 2012. The per-square-foot density fell to 1,072 last year and 875 this year.

“We expected a rapid increase, and then a leveling off, and we’re seeing that,’’ Jones said.

He doesn’t know where the population will settle, but its numbers remain impressive.

About 35 percent of the lake bottom is infested with the invaders, Jones said. The remaining 65 percent of the lake bottom is too soft to support them.

“They’ve maxed out the obvious habitat,’’ he said.

Based on densities he’s documented, Jones calculates there are about 2.2 trillion zebra mussels weighing about 2 billion pounds, dwarfing the lake’s walleye biomass.

“That was eye-opening,’’ Jones said.

Historically, there’s been about 2 million pounds of walleyes in the lake, though officials believe there’s only one-third that amount today due to a puzzling decline in the walleye population.

Officials still aren’t sure what impact, if any, zebra mussels have had on Mille Lacs. The mussels filter vast amounts of water, but water clarity hasn’t changed since they showed up, Jones said. Officials will continue to monitor water chemistry in the lake, to watch for changes.

Walleye reproduction

Jones presided over a public meeting last week in Isle on walleye reproduction in Mille Lacs. About 65 people attended. Another session will be 6:30-8 p.m. Thursday in the New Brighton Community Center in New Brighton.

Walleye reproduction isn’t a problem, Jones told the group, and there’s no value to stocking the lake to try to boost the population. The problem is that large numbers of fish aren’t living to adulthood, and officials don’t know why.

An ongoing study is examining stomach contents of walleyes, northerns and smallmouth bass to determine feeding patterns.

Jones said there are many variables that could be affecting the walleye population, including changing fish populations, climate change, zebra mussels and another invasive, spiny waterfleas, which eat zooplankton — key food for small fish.


Doug Smith • doug.smith@startribune.com

Twitter: @dougsmithstrib


  • 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.


Atlanta - LP: J. Teheran 2 FINAL
Philadelphia - WP: C. Hamels 9
Washington 0 FINAL
Miami 8
Boston 4 FINAL
Minnesota 4
Detroit 2 FINAL
Houston 3
Toronto - WP: C. Hynes 9 FINAL
Boston - LP: D. Hinojosa 7
Tampa Bay - WP: J. Norberto 3 FINAL
NY Yankees - LP: C. Whitley 0
St. Louis 5 FINAL
NY Mets 4
Los Angeles 4 FINAL
Kansas City 4
LA Angels 1 FINAL
Oakland 4
San Diego 8 FINAL
Chicago WSox 2
Chicago WSox 12 FINAL
Seattle 4
Cleveland 2 FINAL
San Francisco 5
Milwaukee 7 FINAL
Chicago Cubs 11
Arizona 3 FINAL
Cincinnati 0
Texas 4 FINAL
Colorado 10
Pittsburgh 3 FINAL
Baltimore 3
Detroit 78 FINAL
Charlotte 102
Philadelphia 93 FINAL
Washington 106
San Antonio 103 FINAL
Orlando 91
Indiana 87 FINAL
Boston 100
Brooklyn 100 FINAL
New York 98
Chicago 91 FINAL
Milwaukee 95
Dallas 135 FINAL
Oklahoma City 131
Sacramento 111 FINAL
Houston 115
Toronto 113 FINAL
Minnesota 99
Denver 84 FINAL
Utah 98
LA Clippers 65 3rd Qtr 5:46
Portland 75
New Orleans 52 2nd Qtr 1:23
LA Lakers 47
Toronto 3 FINAL
Buffalo 4
Philadelphia 4 FINAL
Pittsburgh 1
Edmonton 0 2nd Prd 5:03
Anaheim 4
Colorado 0 2nd Prd
San Jose 0
Loyola-Chicago 63 FINAL
ULM 62
Michigan 65
Temple 58 FINAL
West Virginia 66
Connect with twitterConnect with facebookConnect with Google+Connect with PinterestConnect with PinterestConnect with RssfeedConnect with email newsletters





question of the day

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

Weekly Question