Park to protect lakes from waterflea

Now is the time to act to protect all of Voyageurs National Park’s interior lakes from the latest exotic species to infest them—the spiny waterflea.
These tiny (1/4-5/8”) crustacean zooplankton are native to Eurasia and were introduced into the Great Lakes from the ballast water of ships.
They threaten the park’s aquatic ecosystems and fishing by competing with native fish for food and fouling fishing gear.
Research has shown the spiny waterflea can change the community composition of zooplankton. They also compete directly with juvenile yellow perch and other small fish and minnows for food, which could lead to a decrease in the abundance of these fish.
The above impacts could alter the food web. For instance, yellow perch are an important part of the diet of walleye, so a decrease in yellow perch abundance could hurt walleye growth.
Spiny waterfleas are spread when either live adult waterfleas or viable resting eggs are transferred to a new body of water. They can be transported on bait buckets, anchor ropes, fishing line, boats, waders, and nets.
The bottom line is that any gear that enters infested water and is transferred to another lake or river without being thoroughly dried (12-48 hours) or washed with hot water (above 140° F) can transfer spiny waterfleas.
The Minnesota Department of Natural Resources has designated Rainy Lake, Rainy River, Namakan Lake, and Lake of the Woods as infested waters. The presence of spiny waterflea also has been confirmed in Crane Lake.
The DNR and VNP expect to find the spiny waterflea in Kabetogama and Sand Point Lake since these are connected to infested waters. The designation of these park lakes as infested likely will follow.
The infested waters designation triggers specific invasive species laws that are listed on page 68 of the DNR’s 2007 fishing regulations handbook.
The U.S. National Park Service and DNR are working in concert to develop an extensive monitoring program, as well as best management practices to prevent the spread of the spiny waterflea and other exotic species.
For example, the park immediately stopped all use of the floatplane for monitoring efforts on the interior lakes, and crews carefully dried equipment or used a separate set of research gear on the interior lakes when the spiny waterflea was discovered in Rainy Lake.
The U.S. National Park Service intends to protect Voyageurs’ interior lakes from the spiny waterflea and wants to hear from the public about proposed actions.
Park management is considering the following three short-term measures for protecting the park’s interior lakes:
•artificial bait only (on all interior lakes only);
•no personal boats allowed in interior lakes (the park will continue to provide canoes and row boats for rent through the Boats on Interior Lakes program and Commercial Use Authorizations on Mukooda Lake); and
•no float plane landings on interior lakes
Park staff also will monitor and research the invasion to determine the extent of its spread, and to understand the impacts on aquatic systems.
They also will educate the public about exotics to increase awareness,
and implement best management practices for staff, park partners, and others, to limit the potential for spread to uninfested waters.
Voyageurs seeks input from the public about the proposed measures for protecting the interior lakes. It will accept public comments from March 29-April 30.
Submit your comments on the park’s project website at or mail them to Voyageurs National Park, 3131 Highway 53, International Falls, MN, 56649.
Copies of the complete proposal can be viewed at or at park headquarters.
Voyageurs also will conduct a program about the spiny waterflea and the park’s proposal for any interested party or organization.
To schedule a program, call Kathleen Przybylski at 1-218-283-9821 or e-mail her at
The spiny waterflea is just one example of an aquatic invasive species. With your help and careful actions, together we can try to prevent the spread of the spiny waterflea and other invasive species.
Stop aquatic hitchhikers!