Location: Waterbodies Across the District
Project Type: Capital Projects
Project Status: Active
Current Status: The District is currently tracking carp locations using radio-tags to determine where and when the invasive carp congregate in Spring and Prior Lakes with assistance from WSB & Associates. See below for more details.
You can follow the locations of the tagged carp in Prior and Spring Lake on our Where are the carp? page. There are two maps so you can follow the carp based on their tracking date or fish name. Students from local area classrooms named individual fish and are following the locations of their fish online.
About this Project:
In 2002, Spring Lake and Upper Prior Lake were listed on Minnesota’s 303(d) List of Impaired Waters for nutrient/eutrophication biological indicators and aquatic recreation on both lakes is impaired. The 2012 Spring Lake and Upper Prior Lake TMDL Implementation Plan identified internal loading, including the load from rough fish and curly-leaf pondweed, as a source of roughly half of the phosphorus internal loading to the lakes. The plan went further to identify rough fish management as a way to significantly reduce estimated phosphorus loading.
As a result, the District put together an Integrated Pest Management Plan (IPM) for Common Carp in 2017 to come up with a plan to reduce the Common Carp population in the District. This plan is meant to be a working document which is updated as new strategies and goals are incorporated into the plan.
The District’s carp management project maximizes water quality restoration and remediation by addressing one of the root causes of internal loading identified in the TMDL for Spring and Upper Prior Lakes. Carp stir up sediment from the lake bottom when they forage for food. This re-suspended sediment makes more phosphorus available to phytoplankton and increases the shading effect on native submergent aquatic vegetation. Aquatic vegetation sequesters phosphorus but when the plants do not receive as much sunlight, the plant populations will be reduced and less phosphorus will be stored in the plants. Carp also feed directly on or uproot vegetation, further increasing the level of phosphorus in the water column. By removing the carp from the system, both the phosphorus within the carp carcass and the amount that would typically be excreted will be completely removed, while also abating the release of phosphorus created by foraging behavior.
This project uses integrated pest management (IPM) principles to effectively manage the common carp population within the basin. IPM involves the use of targeted carp removals and barriers, as well as monitoring environmental parameters that can inhibit or promote carp population growth within the Spring and Prior Lakes basins. Adaptive management will use the carp population data that is collected including population and biomass estimates as well as migration routes and winter aggregation locations.
The District is currently undertaking a three year study (2015-2018) with the assistance of WSB & Associates to determine where and when the invasive carp congregate in Spring and Prior Lakes. This information will be used to maximize success in population removal efforts and to identify strategic locations for carp barriers in order to block them from spawning areas.
In November 2015, seven carp from Spring Lake were caught for tagging. The carp were first sedated with clove oil and then a radio-tag was surgically implanted into the fish before it was released back into the lake. Fish in Upper and Lower Prior Lake were a bit more difficult to catch, but eight carp were finally tagged the first week of January 2016. An additional 13 carp in Prior Lake were tagged later in 2016 & 2017. Visit the PLSLWD YouTube Channel to view a video of Tony, from WSB & Associates, inserting radio-tags.
The radio-tags allow the District to track the movements of the invasive carp throughout the two lakes. The goal is to learn where the carp congregate in the lake and surrounding streams throughout the year. This helps improve the success of future carp removal efforts as we can target areas where we know the carp are congregating. Be sure to check out our Where are the Carp? page to track the movements of the carp throughout the lakes!
The radio-tags also enables the District to track the carp in the spring as they head to their spawning areas. Some of the carp spawning areas are located in the streams and wetlands connected to Spring and Prior Lake but located outside of the lakes themselves. Radio-tag tracking helped the District to identify where the carp spawn and carp barriers have been installed to prevent the carp from reaching some of their preferred spawning areas. Denying the carp access to their preferred spawning areas should reduce the carp population growth in Spring and Prior Lake.
January 2017 Seine: A seine event on Spring Lake in January 2017 caught 2,577 carp weighing 17 TONS! That’s over 34,000 pounds of carp removed from Spring Lake. You can check out some awesome photos (with explanatory captions!) from the seine on Facebook page!
Upon discovering all eight of the active tagged Spring Lake fish closely grouped up on the north side of the lake, our partners at WSB & Associates were able to coordinate a seine with a commercial fisherman and his crew. Five tagged carp were ultimately caught along with the 2572 other carp, the average carp weighed 13.2 pounds. The tagged carp were returned to the lake so we can continue to track them and hopefully use them to identify their spawning grounds and future seine locations.
January 2018 Seine: In a record-setting event on January 18th, 2018 the Prior Lake-Spring Lake Watershed District’s consultants, WSB & Associates, coordinated the efforts by Geyer Commercial Fishing, LLC to capture an astounding 35,000 pounds (17 tons) of carp with their nets below the ice of Upper Prior Lake. This big carp haul represents only a portion of the total carp population in Upper Prior Lake. While approximately 3,000 carp were removed, that’s estimated to be just under 20% of the population; an estimated 17,000 carp (approximately 100,000 lbs.) may still be swimming in the lake. The largest fish captured during the netting was over three feet in length and weighed in at a whopping 42 pounds! Scientists estimate that this fish could be over 50 years old. Work continues to locate the carp when they are aggregated on Prior Lake and remove them with another seining event.
The PLSLWD has had successful seines, particularly on Spring Lake in the past, but efforts were sporadic and not done in concert with other control efforts.
Reduction in carp population and improvement of the ecosystem. By removing the carp from the system, both the phosphorus within the carp carcass and the amount that would typically be excreted will be completely removed, while also abating the release of phosphorus created by foraging behavior.
What is a carp seine? Click here to view the video
For SEINE UPDATES: Click here to find out more.
Related News Articles
Colossal Carp Catch on Upper Prior Lake – January 2018
Upper Prior Carp Seine Event details – January 2018
Holy Carp! Spring Lake seine catches 17 tons of carp. – February 2017
Know Thy Enemy – Prior Lake American, November 2015
Stirring up trouble: Solving the carp problem in our lakes – Scott County SCENE, August/September 2015
Fish tourney nets plenty of carp – Prior Lake American, June 2013
Stay updated with this project through the PLSLWD News and Events Blog.
WSB & Associates
Shakopee Mdewakanton Sioux Community (SMSC)
City of Prior Lake
Spring Lake Association
Prior Lake Association
Funding for this project was partially provided by the Minnesota Pollution Control Agency through a Grant from the State’s Clean Water Partnership Grant Fund.
Clean Water Partnership Grant
This grant program is managed by the MN Pollution Control Agency (PCA). This three year grant founded carp management in Prior Lake and Spring Lake from 2015-2018. Management activities included tagging 30 carp with radio-tags, tracking the carp in Prior and Spring Lakes to determine seasonal aggregation areas and spring spawning areas and installing carp barriers in strategic locations to prevent carp from reaching their preferred spawning areas. Radio-tag tracking was also used to help improve the success of carp removals; the radio-tags allowed the District to identify went and where the carp were aggregating and then seine those areas to remove carp.
Conservation Partners Legacy Grant
This grant is funded by the Clean Water, Land & Legacy Amendment through the MN Department of Natural Resources (DNR). This grant funded the installation of a drum barrier at the District’s desiltation pond for the ferric chloride facility to prevent carp from using the pond for spawning.