Measures target spiny waterfleas

In 2006, Voyageurs National Park confirmed the presence of spiny waterfleas in Rainy and Namakan lakes.
The Minnesota DNR has confirmed the presence of spiny waterfleas in Crane Lake, too.
The DNR and park expect to find the spiny waterflea in Kabetogama and Sand Point lakes since these lakes are connected to infested waters.
Now it is important for the U.S. National Park Service to protect the park’s interior lakes while biologists determine the extent of the spiny waterflea infestation in the park.
From March 30 through April 30, Voyageurs National Park accepted comments on three proposed interim measures to protect the park’s interior lakes from the spiny water flea.
Interim measures proposed included:
•artificial bait only (on all interior lakes only);
•no privately-owned watercraft 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
During the comment period, the park received three comments via its online planning website, one comment via e-mail, and about five comments from commercial use authorization (CUA) permit-holders.
Most respondents were in favour of the interim measures, though one person expressed concern the restriction for personal boats would impact visitor use.
One CUA permit-holder suggested the park place additional rental boats on interior lakes.
The park acknowledges that not allowing personal boats on interior lakes may impact some visitors. But it estimates the number of visitors impacted would be less than 100 based on field observations.
After reviewing the comments received and information known about spiny waterfleas, the park adopted the interim measures effective May 10.
The need to continue restrictions will be assessed before the 2008 visitor season.
Voyageurs also will implement the following action plan:
•sample many interior lakes to check for the presence of spiny waterfleas and to document zooplankton communities;
•implement best management practices for preventing the spread of exotic species, especially the spiny waterflea;
•drain water from live wells, bilges, and bait buckets before leaving infested waters;
•dry your watercraft and all gear used in infested waters for at least 12 hours;
•dispose of bait in the trash, not in the lake;
•spray your watercraft with 140 degree F water for at least one minute
to remove gelatinous materials and plants from all equipment;
•in co-operation with Minnesota Department of Natural Resources, conduct public education at boat launch areas about exotic species; and
•provide information about spiny waterfleas and other invasive species at park visitor centers, in park publications, and on the park website (
Spiny waterfleas are tiny (1/4-5/8”) crustacean zooplankton native to Eurasia. They 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.
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!