Invasive Species

November 2019 Update

The MN DNR has confirmed zebra mussel larvae (veligers) in a water sample taken from Ten Mile Lake near Hackensack. While no adult or juvenile zebra mussels have yet been reported, the number of veligers indicates a reproducing population. Consequently, Ten Mile Lake will be added to the infested waters list for zebra mussels. Earlier this summer Hand Lake was also confirmed to be infested with zebra mussels. For more information about infested waters in Minnesota: More information is available at

Your WLBCR Lakes Association will continue to promote the “Clean, Drain, Dispose” steps that are always legally required on all water bodies, and we will work with the DNR and Cass County to provide current information to our members. Let’s continue to be diligent with taking necessary precautions to prevent AIS from entering our lakes. If you think you may have found some aquatic invasive species, please contact Cindy Gackle, 612-751-7921 or Randy Noecker, 319-533-8032, and we will contact the DNR AIS Specialist for our region.

In the News

Zebra mussel genome has been identified by researchers at MAISRC (MN AIS Research Center) See StarTribune article of July 11, 2019:

MAISRC website:

Minnesota Infested Waters

The Minnesota Department of Natural Resources (DNR) regularly updates the state infested waters list, which includes Minnesota lakes and rivers containing certain aquatic invasive species. There is also a downloadable Excel spreadsheet, which is the most complete version of the infested waters list.

Eyes on the Lake

This feature will help us all with learning what plants are native and healthy for our lakes vs. the invasive plants. We hope you find this information helpful. Thanks for helping to keep our waters clean.

Eyes on the Lake – Zebra Mussels

Keys to Identify:

  • Stripes are generally in zigzag patterns
  • Pattern is variable; some may lack striping altogether and can be solid tan or brown
  • Have a flat edge and won’t topple over when set on its edge
  • Shells form straight light when closed
  • Range from 1/8 of an inch to 2 inches; adults are typically fingernail sized.

Looks similar to:

  • Other invasive invertebrates: Quagga mussels, Asian clams & Chinese mystery snails.
  • Native invertebrates: native snails and native mussels.

Where to look:

  • Often found attached to submerged objects (such as boats and docks, as well as plants and rocks)
  • Newly settled mussels are usually in shallow areas; adults are common in depths of 10-20 feet.

Zebra Mussel Impact:

  • Encrusts equipment, such as boat motors and hulls, which reduces performance and efficiency, and is costly to clean and repair
  • Swimmers and pets can cut their feet on zebra mussels attached to rocks, docks, swim rafts and ladders
  • Creates a costly problem for power plants, cities and residents when they clog water intakes.
  • Filters tiny food particles out of the water, which can reduce available food for larval fish and other animals, and can increase aquatic plant growth as a result of increased water clarity.
  • Attaches to and kill native mussels.

What we should know:

  • A single zebra mussel can filter one quart of water per day while feeding primarily on algae.
  • A female can produce 100,000 to 500,000 eggs per year. Fertilized eggs develop into microscopic, free-living larvae, called "veligers," that form shells. After two to three weeks, the veligers settle and attach to a firm surface using tiny fibers called byssal threads. Beds of zebra mussels can reach tens-of-thousands within a single square yard.
  • Microscopic larvae (veligers) can survive in water contained in bait buckets, live wells, bilge areas, ballast tanks, motors and other water containing devices.
  • Zebra mussels are unintentionally spread through the movement of water-related equipment, attaching to boats, docks, swim rafts and boat lifts, as well as aquatic plants.
  • Adult mussels can survive out of water – less than 5 days in dry conditions, but up to 21 days in very wet conditions (such as, inside dock/lift pipes).
  • It is a prohibited invasive species and it is unlawful (a misdemeanor) to possess, import, purchase, transport, or introduce this species except under a permit for disposal, control, research, or education.

How to prevent zebra mussels:

Clean watercraft of all aquatic plants and prohibited invasive species.

Drain all water, including live wells and bait water. Remove boat drain plugs; keep them out during transport.

Dispose of unwanted bait in the trash.

Dry docks, lifts, swim rafts and other equipment for at least 21 days before placing equipment into another water body.


AIS Identification Guide: A Minnesota Handbook,

MN DNR website:

Eyes on the Lake - Eurasian Milfoil

Is It Eurasian Milfoil or Northern Milfoil?

Eurasian watermilfoil looks similar to many native, beneficial watermilfoils found in Minnesota lakes and rivers. Its common native look-alike is northern watermilfoil. It’s spread primarily through the movement of water-related equipment. Plant fragments can get tangled on boats, trailers, motors, anchors and other water-related equipment. All it takes is a single plant fragment to start a new population. It is a prohibited invasive species in Minnesota, which means it is unlawful (a misdemeanor) to possess, import, purchase, transport or introduce these species except under a permit for disposal, control, research or education.

Eurasian watermilfoil impacts:

  • Dense mats at the water’s surface inhibit water recreationists.
  • Overtakes habitat and outcompetes native aquatic plants, potentially lowering diversity.
  • Provides unsuitable shelter, food, and nesting habitat for native animals.


AIS Identification Guide: A Minnesota Handbook,

MN DNR website:

Keys to Identifying the 2 Types of Milfoil


  • Featherly looking with 4 leaves per whorl
  • Leaves have central axis with 12-20 leaflet pairs
  • Can grow up to 10 feet long
  • Produces pink & white flowers on spike above surface
  • Flowers 2x/year; usually mid-June & late-July
  • Leaves become limp when taken out of water
  • Grows best in 3-15 feet
  • 4 leaves per whorl
  • Leaves have central axis
  • Each leaf has 4-11 leaflet pairs
  • Forms winter bud in late fall and winter
  • Leaves are rigid when taken out of water
  • Grows underwater in depths of up to 20 feet

Reporting a Suspected Invasive Species

If you suspect a new infestation of an aquatic invasive plant or animal, note the date, the exact location, and, if possible, take several photos and keep the specimen (a plastic bag is fine). Then, be sure to contact us or the AIS specialist for our region:

For More Information

o MAISRC (MN AIS Research Center):

o MN Lakes & Rivers Advocates:

o MN Sea Grant:

o Wildlife Forever:

o Association of Cass County Lakes (ACCL):

2019 Update

Good News

  • Our lakes are clean, and no AIS infestation has been found.
  • Zebra mussel genome has been identified by researchers at MAISRC (MN AIS Research Center)
  • 2019 legislature approved an AIS fee increase on a 3-year boat registration. Effective 7/1/2016 fees increased from $5 to $10.60. This is the first increase since 1993. This will significantly enhance DNR’s

AIS Prevention and Management

  • Cass County Watercraft Inspection for both Little Boy and Wabedo began on fishing opener weekend, May 11th . This program is managed by Levy Bergstrom, AIS Lake Technician for Cass County Environmental Services Department (ESD)/Soil and Water Conservation District (SWCD). Both lakes are covered on most weekends throughout this lake season. Read the Cass County Annual AIS report
  • Potential AIS infestation twice this season by the inspectors: curly leaf pondweed and water that hadn’t yet been drained from a boat that had just been in Lake Michigan. Considering that there are more days of the week that aren’t covered by inspectors, the potential is real.
  • Cass County still needs watercraft inspectors for the season. Both Level I and II positions available. If interested, contact: Penmac Staffing Services, Inc. in Brainerd – Rachel Hanson, 218-824-9675,
  • AIS Detector volunteers completed training on June 7th through MAISRC (MN AIS Research Center):
    • Gayl and Randy Hohbein and Bob Krahn, all from Wabedo. Thank You!

Summary of 2018 Watercraft Inspections:

    • Cass County covered 102 days of inspections with 21,808 inspections:


  • Total inspection days = 40
  • Total inspections = 630
  • Total inspection hours = 367.75
  • Inspections/day = 15.75
  • AIS monies spent = $7,568.70


  • Total inspection days = 23
  • Total inspections = 184
  • Total inspection hours = 216.25
  • Inspections/day = 8
  • AIS monies spent = $4,450.43

WLBCR Current Projects

  • Lake Association AIS Plan in process of being updated.
  • AIS towels were distributed during Annual Meeting and watercraft inspectors distribute for AIS prevention reminders.
  • PVC Zebra Mussel “detectors” at public accesses of both Little Boy and Wabedo Lakes, Little Boy Resort and Diamond Crest Resort, and 5 private docks.
  • Decontamination station maps and AIS education handout are stocked at both lake access kiosks.

Funding AIS Prevention and Remediation

In 2012 we established a dedicated fund for AIS prevention and remediation. This fund will be used to prevent AIS from entering our lakes or will be used to eradicate or manage AIS if it does get into our lakes. You will be asked to donate to this fund when you renew your membership or you can send a check to WLBCR Lakes Assoc, PO Box 133, Longville, MN 56655 and indicate the check is for the AIS Fund.

2014 Update

WLBCR Lakes Association adopted an AIS Plan. The plan we adopted is somewhat generic and will be updated with more specific activities and projects in the coming months. We quickly adopted the generic plan in case we need to have one in place for AIS inspections next year. Here is the plan: WLBCR AIS Plan

2013 Update

County created a plan for AIS prevention. It is holding open houses to go over the plan and take input. Please review the plan and attend the meeting if you can. The meeting dates are: Wednesday, August 7 from 4-7 pm in the Rotary Room of the Walker Area Community Center and Thursday, August 8 from 4-6 pm in the Board Room at the Cass County Land Department, Backus. The plan is open for comments through Friday, August 30. Here is a link to the proposed plan. Cass County AIS Plan

The State of Minnesota also has a plan created in 2009. See it here: State Plan

2012 update

The Minnesota DNR, in cooperation with Linder Media, has created a video called Minnesota Waters at Risk discussing AIS issues.

2012 DNR AIS Video (about 25 minutes long so plan accordingly)

2011 Update

In 2011 the AIS committee scheduled DNR training of 17 boat inspector volunteers. These people spend time at the public accesses (normally on weekends) and discuss AIS with boaters entering and leaving our lakes. They also inspect the boats for presence of AIS and talk about the new AIS laws and how they affect boaters and fisherman.

Our lake association takes the issue of invasive species very seriously. Zebra mussels appear to be the most serious threat we face today. Once they are in a lake, there is no known method to control or contain them. The only way to stop them is to not let them into our lakes.

Here are links to a couple videos that discuss the zebra mussel issue in the Great Lakes:

TV segments (produced by Wildlife Forever)

You Tube Video (created by Great Lakes Restoration Initiative)

2010 Update

In 2010 we created a new committee headed by Randy Helland that deals with Aquatic Invasive Species (AIS). This first year was very successful.

Additional signs were placed at the two public accesses on Little Boy and Wabedo Lakes as well as the resorts that instructed the boat owner on how to prepare the boat before and after putting it in the water. Signs were also placed dealing with AIS and also showing the "Sensitive Shoreline" areas.

We invited Darrin Hoverson of the Minnesota DNR to a Board meeting to discuss AIS. Dick Sternberg of Little Boy Lake and former DNR did a presentation on zebra mussels at our annual meeting. Doug Schultz of the Walker DNR came and trained our Beach Captains.

Property owners volunteered to be Beach Captains. These Captains each took a section of shoreline and looked for AIS in the near-shore areas of their assigned sections. These shoreline checks are performed in late August when the vegetation is at its peak growth.