Common carp uproot plants and stir up lake bottoms, degrading the habitats they live in and releasing nutrients that feed algae blooms. They also crowd out other species of fish due to the unprecedented level at which they populate.
To address this the Minnehaha Creek Watershed District (MCWD), in coordination with Three Rivers Park District, Carver County, the City of Victoria, and the rest of the Six Mile Creek-Halsted Bay Subwatershed Partnership, completed their first removal of invasive common carp on Friday, Sept. 7th at Steiger Lake in Victoria.
This first round of carp removal kicked off what the group anticipates to be a multi-pronged, ten-year effort to improve water quality and wildlife habitat in the southwestern portion of the Minnehaha Creek watershed.
“The carp management was identified as a priority strategy because of the damage that they do to lakes. They stir up lake bottoms, they cause algae blooms, they crowd out other fish,” says Telly Mamayek, Director of Communications and Education for the MCWD. “They populate the lakes at an unprecedented level and so we’re really working to control the carp population here in this geography, which is really a series of fourteen connected lakes that all feed into Lake Minnetonka.”
The goal is to remove about 1,000 carp from Steiger Lake. Once removed the carp from Steiger Lake were brought to the wildlife center where they will feed some of the animals, such as wolves. Carp are also utilized by commercial fishermen who commercialize the product.
Carp are caught in the fall using a bait and box approach. Cracked corn is used to bait the fish into specific locations and train their behavior to return to the same locations every day, as carp are generally the only fish interested in feeding on the corn.
“Once we have enough carp feeding the crew will come out and they’ll actually in the middle of the night, in the early morning, they’ll actually pull some ropes that will release the sides of the net and trapping the carp within those nets and remove them. And we’ll do multiple efforts with this throughout the fall,” Eric Fieldseth, an Aquatic Ecologist for the MCWD, explains.
The carp management plan is based on data from a three-year study by the University of Minnesota’s Aquatic Invasive Species Research Center. The researchers found an unprecedented number of common carp in the Six Mile Creek system, including Lake Minnetonka’s Halsted Bay. They also identified where the carp are spawning and determined their migration patterns. The findings helped shape a management strategy that includes removing adult carp, installing carp barriers, and aerating lakes to ensure the winter survival of bluegill sunfish (which feed on carp eggs).
During the carp removal process, the MCWD will be implanting radio tags in carp to monitor their movement, which will help with future removal efforts. Monitoring will be done throughout this project to track carp populations as removal occurs, to evaluate the potential for carp reproduction in the carp nursery lakes, and to assess the ecological impact of the carp removal.
In addition to removing and tagging carp, the MCWD will install barriers to stop carp from moving into and out of Wassermann Lake, Crown College Pond, and Mud Lake, containing the invasive fish and blocking their access to spawning locations.
Rounding out the management strategy, the MCWD will be installing aeration units in Marsh, Sunny, North Lundsten, South Lundsten, and Mud Lakes to maintain their oxygen levels through the winter. The goal is to ensure the survival of bluegill sunfish so they can feed on carp eggs in the spring.
This multi-pronged approach to carp management increases the chances of a sustainable effort that provides long-term protection from invasive common carp across the subwatershed.
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