Zebra Mussel Sampler

Boat Launch AIS Inspection Hours

Aquatic Invasive Species (AIS) inspections are done May 1 - December 1 by DNR trained AIS inspectors during the following hours. The public boat launches are locked during non-launch hours.

May 1 – September 16
Daily:  6 am–10 pm

September 17 – October 8
Daily:  6 am–9 pm

October 9 – November 4
Daily:  7 am–8 pm, Inspector On-Call*

November 5 – December 1
Daily:  8 am–6 pm, Inspector On-Call*

*On-Call Program (October 9 - December 1)

During our fall on-call inspection program please call the following numbers to get an inspection.

  • Bde Maka Ska (formerly Lake Calhoun): 612-346-5547
  • Lake Harriet: 612-346-5547
  • Lake Nokomis: 612-346-5428

Boat launches will be open for each boater who calls for entry and exit inspections. Wait time is generally less than 10 minutes. Appointments not accepted. Boaters not exiting the lake by closing time must secure their boat and return for it the next day.

Help Protect Your Waters

If you are a lake user please do your part to prevent the transport of AIS from one lake, river or creek to another. Protect Minnesota’s waters by following the state AIS laws.

MPRB’s Watercraft Education and Inspection Program

In April 2013 the MPRB implemented a Watercraft Education and Inspection program. All watercraft and water related equipment passing through boat launches at Lakes Harriet, Nokomis, and Bde Maka Ska are required to have inspections looking for aquatic invasive species (AIS).  Boats launched from the shoreline are not required to have an inspection. Boat launches are closed when inspectors are not on site. Be sure to check for current boat launch hours prior to your visit.

In addition to watercraft inspections, the MPRB also implements the following actions to prevent the spread of AIS:

  • AIS education and outreach
  • Boat launch usage data collection at the launches
  • Signage and additional trash receptacles to encourage proper bait disposal at launches, fishing docks, and high use shoreline fishing areas
  • Early AIS detection monitoring
  • Staff education
  • Developed an AIS Rapid Response Plan

AIS Prevention in the Future

Park Board staff will continue to evaluate and improve its AIS prevention program from year to year. AIS inspectors collect data during inspections to help inform decisions about future efforts.

Enforcement

Under Minnesota law, it is illegal to transport aquatic plants and animals as well as water, to and from water bodies. Failure to comply with Minnesota AIS regulations can result in fines up to $1,000.

You Must:

Clean visible aquatic plants, zebra mussels and other prohibited species from watercraft, trailers, and equipment before transporting from any water access.

Drain water from bilge, live well, motor, ballast tanks, and portable bait containers before leaving water accesses or shoreline property.

Dispose of unwanted bait in the trash or refill bait container with bottled or tap water.

Keep drain plug out and water-draining devices open while transporting watercraft.

You May Not:

Transport aquatic plants, water, or prohibited invasive species such as zebra mussels or Eurasian watermilfoil.

Dump live bait into state waters, on shore, or on the ground.

Launch, or attempt to place watercraft, trailers or equipment with aquatic plants, zebra mussels, or prohibited invasive species into any state waters.

Additional Recommended Precautions:

To remove or kill hard-to-see aquatic invasive species before moving to other water bodies the following is advised:

  • Spray watercraft and water-related equipment with high-pressure water and rinse with very hot water and/or
  • Dry boats and water-related equipment for at least five days
  • Report new sightings of aquatic invasive species. If you suspect a new infestation of an invasive plant or animal, save a specimen and report it to a local natural resource office.

Additional AIS Prevention Information

AIS Threat

AIS Threat to Minneapolis Waters

Minnesota's waterways are threatened by a number of aquatic invasive species (AIS). AIS are not native to Minnesota. They can cause economic and environmental harm as well as having negative impacts on human health. Once an AIS is established it is nearly impossible to eliminate. The Minneapolis Park and Recreation Board (MPRB) is taking steps to ensure that our water resources can be enjoyed for years to come by committing to AIS prevention efforts. The MPRB has been actively monitoring AIS since the late 1980s when Eurasian watermilfoil was first discovered in the Chain of Lakes.

Some of the City’s water bodies do contain AIS, such as Eurasian watermilfoil, zebra mussels, and common carp. There are, however, several species that have not established themselves in our lakes. New infestations of AIS occur in neighboring lakes and rivers throughout the state and MPRB’s inspection program is designed to slow the spread of those species as long as possible without restricting boater access to the lake.

Visit the DNR's website for the most up-to-date infested waters list, detailed biological information and current regulations on aquatic invasive species. 

Successful aquatic plant management is key to providing recreational opportunities in Minneapolis lakes. Plants that grow in and around water can have an impact on the long-term health of our area lakes. For this reason, the MPRB completes aquatic plant surveys on lakes every two to three years. These surveys document the increase or decrease in current aquatic plant species and changes in biodiversity.

View the MPRB Water Resources Report for detailed annual monitoring data, data collection methods, and more.

AIS Management

mechanical harvester boat
Mechanical Harvester

AIS Management Methods

Harvesting

Harvesting is currently the best management option that the MPRB has to control aquatic plants, including Eurasian watermilfoil, an aquatic invasive species that is prevalent in many Minneapolis lakes. Minnesota DNR-issued permits limit the area of milfoil that can be harvested each year.

Harvesting is done primarily in swimming areas and around boat launches. A machine called a mechanical harvester removes plants that are in the top six feet of water. This temporarily allows for trouble-free boating and swimming, and allows sunlight to penetrate to native plants below.

divers pulling eurasian watermilfoil

Divers using SCUBA gear hand pull plants in areas that are inaccessible or hard to reach with a mechanical harvester.




Species

Species Currently Found in Minneapolis Waters

 

Eurasian Watermilfoil (Myriophyllum spicatum)

eurasian watermilfoil

Eurasian watermilfoil is a non-native aquatic invasive species that has been an ongoing concern in several Minneapolis lakes. From an ecological standpoint it outcompetes native species and alters the habitat for fish and other organisms. Milfoil grows vigorously in water less than 16 ft. and often forms dense floating mats that interfere with boating and swimming. The MPRB participates in aquatic plant management to allow for the many recreational opportunities available on our Minneapolis lakes. Eurasian watermilfoil can be easily transported from one lake to another on boats and trailers. Boaters should be aware of this problem and clean all aquatic vegetation from boat, trailer and motor parts before leaving the boat launch.

Curly Leaf Pondweed (Potamogeton crispus)

Curly Leaf Pondweed (Potamogeton crispus)

Curly leaf pondweed was first documented in MPRB lakes in 1974. This species likely hitchhiked to North America with European carp, an intentionally introduced species.  Both have subsequently become invasive throughout Minnesota. Curly leaf pondweed has an unusual life cycle in that it is an annual that begins growing under the ice and dies off in June. In a spring that follows a mild winter curly leaf pond weed can produce mats of vegetation that cause a nuisance for lake users. In harsh winters this plant shows lower levels of growth.

Purple Loosestrife (Lythrum salicaria)

Purple Loosestrife (Lythrum salicaria)

Purple loosestrife (Lythrum salicaria) is a perennial featuring long spikes of colorful purple-pink flowers that begins blooming in July. Records show that Purple loosestrife has been in North America since the 1830s. The plant came to North America in the ballast of ships from Europe and was also introduced as a medicinal and ornamental plant. In Minnesota, records show that in the 1920s several garden clubs introduced purple loosestrife into wetlands for “beautification” purposes. Purple loosestrife invades wetland and lakeshore habitats, displacing native plant communities and destroying habitat and food sources for waterfowl and other wetland wildlife. Producing half a million seeds per square meter allows purple loosestrife to easily re-establish itself.

Since the late 1990s the Minneapolis Park and Recreation Board has collaborated with the Minnesota Department of Natural Resources to use a biocontrol method on purple loosestrife. The biocontrol is a leaf feeding beetle that feeds on the leaves of the plant. After several years of defoliation, the plant declines and dies.

Using biocontrol methods for controlling invasive plants is not a quick method. Extremely cold winters, wet spring/summers and seasonally flooded areas do not favor establishment of leaf-feeding beetles. Fluctuations in temperature and flooding may reduce beetle populations. 

Yellow Iris (Iris pseudacorus)

The yellow iris is a regulated invasive species in Minnesota. This Eurasian species is sold commercially for use in garden pools but when it escapes it competes with native shore land vegetation. Residents should take care not to allow aquarium and landscape plants or animals to escape into the surrounding environment.

Flowering Rush (Butomus umbellatus)

Flowering Rush  (Butomus umbellatus)

Flowering rush is actively expanding throughout southern Canada and the northern United States and is on the Minnesota DNR Prohibited Invasive Species list.  This Eurasian plant has been sold commercially for use in garden pools. Flowering rush is very aggressive and competes with native shore land vegetation.

Reed Canary Grass (Phalaris arundinacea)

Reed canary grass is a major threat to natural wetlands. It outcompetes most native species and forms large, single-species stands, with which other species cannot compete. This Eurasian species has been planted throughout the U.S. since the 1800s for forage and erosion control. While many Minnesota state agencies have removed it from their planting lists, it is still being planted in the state.

Zebra Mussels (Dreissena polymorpha)

Zebra Mussels (Dreissena polymorpha)

Zebra mussels are freshwater bivalve mollusks native to southeastern Russia. They hitchhiked to North America in ballast water from the Black Sea and were first identified in the Great Lakes in 1988. By 1990 they were established in all of the Great Lakes and began to move into major river systems.  By 1992, zebra mussels became established in the Mississippi River. 

In 2010, zebra mussels were confirmed in Lake Minnetonka and at the outlet to Minnehaha Creek. Lake Hiawatha is directly connected to Minnehaha Creek and Nokomis has close proximity but is physically separated by a weir. Both Hiawatha and Nokomis were designated infested due to their connection/proximity to Minnehaha Creek. Zebra mussels were discovered on a sampling device in Lake Hiawatha in 2013 confirming the designation. One live, adult zebra mussel was discovered on September 8, 2017 by MPRB staff on a boat cover recovered from the bottom of Lake Harriet. After the initial discovery, no additional zebra mussels were found after 67 hours of searching.  Lake Harriet has been designated as infested and will continue to be monitored closely as part of the MPRB AIS early detection program.  Learn more about the zebra mussel in Lake Harriet.

Zebra mussels spread easily because of their biology. Unlike native mussels, zebra mussels do not need a larval host. Faster growth rates and a shorter time to maturity also give non-native zebra mussels an advantage over native mussels. They can attach themselves to any solid surface (including: pipes, boat hulls, rocks, wood, vegetation, other mussels) and can significantly alter the ecology of a waterbody. There are no practical ways to eradicate zebra mussels from a natural system once they are established. The DNR website provides additional useful information about the infestation of zebra mussels in Minnesota.

The MPRB has developed a Zebra Mussel Action Plan [PDF] to guide the organization on prevention efforts against further infestations.

Chinese Mystery Snails (Bellamya chinensis)

Chinese Mystery Snails (Bellamya chinensis)

Chinese mystery snails have been identified by the DNR in Loring Pond, Grass Lake, and Powderhorn Lake. This snail is native to Asia, was introduced to California in 1892, and was found on the east coast of the United States by 1915. This species has the capability of growing to high densities and tends to have boom and bust cycles. When the population reaches the bust portion of the cycle, large concentrations of dead snails can ring the shoreline. This species is a popular aquarium snail, and when found, is likely an aquarium release.

European Carp (Cyprinus carpio) and Goldfish (Carassius auratus)

Each of these species can reproduce to very high densities. These bottom-feeding fish are capable of disturbing lake beds to the extent that water quality can be diminished. Lakes with an overgrowth of European carp typically have high phosphorus concentrations, low water clarity, and little to no aquatic plant growth. Carp eat vegetation and can alter or destroy the aquatic plant community in a lake.  

Species of Concern to Minneapolis Waterways

 

Brazilian Waterweed (Egeria densa)

Brazilian Waterweed (Egeria densa)

In August of 2007, Brazilian waterweed was identified in Powderhorn Lake. This species is native to South America and used extensively in aquariums and water gardens. It is likely that it was introduced into the lake through an aquarium release. The DNR treated the stands of waterweed with an herbicide approved for aquatic use, and it has not been seen in Powderhorn since this treatment. Residents are encouraged to dispose of aquarium and water garden plants and animals as recommended by the MNDNR rather than releasing them into Minneapolis waterways where they can do extensive damage to the environment.

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Other Aquatic Invasive Species of Concern


FAQ

Frequently Asked Questions about the MPRB AIS Watercraft Inspection and Education Program

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What is the goal of the program?


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When will inspections and launch hours be in effect?


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Why is the Park Board concerned about AIS?


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Isn’t it too late to prevent the spread of AIS?


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Which AIS is the Park Board aiming to keep out of Minneapolis lakes?


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How does the AIS education and inspection program affect canoes, kayaks and sailboats?


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How was the inspection/launch season determined?


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How long do inspections take?


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What if I refuse to have my boat inspected?


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Which lakes or water bodies will be affected by the AIS inspections?


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What if I want to go fishing on the lakes before the launch opens or after it closes?


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Can I use my gas-powered motor on any of the lakes?


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What is proper bait disposal and how does it protect against AIS?


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What can I do to stop the spread of AIS?