Using management techniques developed on the Phalen Chain of Lakes, we’re now working to reduce carp and improve water quality in the Lake Owasso system.
Carp management in Lake Owasso and connected lakes is part of our goal to control phosphorous loading in these waters. As carp root for food along the lake bottom, they stir up nutrient-rich sediment, which in turn contributes to turbid water and algae blooms.
With four interconnected lakes (Owasso, Wabasso, Bennet and Grass) and 12 shallow ponds, the Lake Owasso system offers prime habitat for carp to potentially out-compete native game fish, uproot aquatic vegetation and harm water quality.
We enlisted Carp Solutions to conduct a general population assessment through electrofishing in summer 2017. After calculating a biomass estimate, they found that each lake in the chain contained more than 100 pounds of carp per acre, the threshold generally considered to inhibit water quality. Most concerning were Lake Owasso and Lake Wabasso, which each turned up more than 400 pounds of carp per acre.
The team marked over 200 carp with a fin clip as part of a mark-and-recapture study to verify these estimated population numbers, and they surgically implanted radio transmitters in 20 adult carp. Since carp tend to travel in dense schools, the radio-tagged fish will help us track seasonal movements of the larger population. This allows us to pinpoint the best locations to efficiently harvest carp, along with where to place barriers that prevent them from accessing shallow spawning and nursery areas.
While netting adult fish should put a dent in the carp population, confirming spring spawning locations could be key to a long-term management strategy. Shallow ponds and wetlands often serve as carp nurseries where they can hatch by the millions and grow in relative safety from predators. In spring 2018, we installed PVC and wire mesh barriers at five key locations on the Lake Owasso Chain, and we successfully removed several hundred carp from these areas using handheld nets and electrofishing equipment.
Since 2009, carp management in the Phalen Chain has reduced carp density by over 60 percent. Among those efforts was eliminating carp in Casey Lake (a former carp nursery in North St. Paul) by drawing down the water level, allowing carp to winterkill, and then stocking bluegills and largemouth bass. Tracking the movements of Owasso carp could help identify similar carp nursery locations and allow us to rein in these prolific fish.
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
Carp control expands to Lake Owasso Chain