The Owasso Chain of Lakes: Reducing the carp population to improve water quality
Carp Management – Lake Owasso Chain
Project Details
| Cities | Shoreview, Roseville |
| Subwatersheds | Lake Owasso, Lake Wabasso, Bennett Lake |
| Timeline | Ongoing since 2017 |
| Cost | $40,000 (2021 budget) |
| Funding sources | District funds |
| Partners | Carp Solutions, Ramsey County, University of Minnesota, Minnesota DNR, City of Shoreview,City of Roseville |
Overview
The common carp is a highly invasive fish species from Eurasia. Due to its ability to overpopulate waters and its bottom-feeding behavior, it’s considered one of the world’s most pervasive and damaging species. Carp root around on the lake bottom, stirring up sediments, dislodging beneficial aquatic plants, and releasing nutrients into the water column that can cause algal blooms. Especially in shallow lakes, carp can severely impact water quality. In 2017, because of the potential risk carp posed to water quality, the Watershed contracted with Carp Solutions to assess carp population dynamics and control strategies in the Owasso Chain.
Work Completed
To generate solid carp population estimates for the Chain, we used a mix of boat electro-fishing, mark-recapture (fin clipping), and implanting radio tags in a sample of carp. Initial surveys found that the main Chain of Lakes had carp biomass levels well over 100 pounds/acre, the threshold where water quality impacts are generally evident. Because of this finding, a comprehensive management plan was then implemented to reduce the carp population below the critical water quality threshold.
We have employed baited box-netting along the shore in Lakes Owasso, Wabasso, and Bennett to capture adult carp and reduce the overall population. In addition, we installed PVC pipe barriers to limit carp movement into key spawning areas. During May, carp begin to move out of the main lakes and into ponds and wetlands to spawn. When carp school up at the barriers, we have had a good amount of success hand netting fish around these structures. Thus, the barriers are an effective tool in preventing spawning migrations and also provide an opportunity for efficient carp capture.
Project Goals
– Substantially reduce the adult carp population in the main chain of lakes below 100 pounds/acre using management methods developed through the Phalen Chain of Lakes Carp Research Project
-Block prime spawning areas during spring migration to reduce carp recruitment
-Continue to monitor the carp population to assess management effectiveness
-Use adaptive carp management over the long-term to sustain low carp numbers
Impact
In all of the main lakes, carp numbers have significantly declined due to the management activities. In 2018, carp biomass in Owasso, Wabasso, and Bennett was at or below the 100 pound/acre threshold. Through continued control efforts in 2019-21, we could further reduce carp biomass levels well below the threshold (see graphs below). In addition, we have not detected any young carp in the main lakes, suggesting that the barrier installation has limited carp spawning in connected ponds and wetlands.
In 2022, we plan to conduct intensive netting around the barriers. In the next few years, we will be assessing water quality trends to determine if there is improvement related to the reduction in the carp population.
More information
As interest in management of common carp populations grows, so does Carp Solutions (Star Tribune)
Box nets and barriers help manage common carp on Owasso Chain