Goal is to protect Martin, Typo lakes
Watershed managers are looking to give the boot to some unwanted residents in Martin and Typo lakes, located in Linwood and Oxford townships. Both lakes have an abundance of common carp, which contribute to poor water quality and crowd out game fish. A series of barriers are planned which will isolate the carp, blocking their migrations between favored spawning and wintering areas as well as making commercial removal of the rough fish more effective.
Construction could begin this year, and should be completed by the end of 2015.
“The benefits to water quality will not be seen immediately,” said Jamie Schurbon, the Water Resource Specialist at the Anoka Conservation District. “We won’t be able to evaluate true success until after a few years. Typo Lake in particular is so turbid that we may measure lower levels of nutrients, algae, and sediment, but the casual observer will still likely see a very brown or green lake. But it is measurable, significant movement in the right direction. Effects will be more noticeable at Martin Lake, where water quality is somewhat better.”
Solving the problem
Both lakes fail to meet state water quality standards due to excessive phosphorus, which fuels algae blooms. Water in both lakes often appears strongly green or brown. Typo Lake has especially poor water quality, with summertime transparency of less than six inches.
Carp are not the only cause of poor water quality, but are a significant contributor. They disturb the bottom when feeding and spawning, stirring phosphorus and sediment into the water column, and uproot plants important to water quality and game fish. Also, they have poor digestive systems, so they eat a lot and fertilize the water with nutrient-rich manure. Each female carp is capable of producing 300,000 eggs in a single spawn.
Barriers are an effective strategy for carp control because Typo and Martin lake each provide something important for carp. Martin Lake is deeper, and good for overwintering. Typo Lake and Typo Creek are shallow and good for spawning. Stopping migrations between the lakes will reduce overwintering survival and spawning success.
Commercial carp harvests are anticipated once barriers are in place. Past commercial carp harvests on these lakes have had noticeable, but short-lived benefits. Harvests were limited to one lake, and carp quickly recolonized from the other lake, creek, or nearby wetlands.
Minnesota DNR Fisheries specialists are advising this project to ensure it does not have a negative effect on game fish. Both lakes will continue to be stocked as they are today.
The barriers will be at the Typo Lake outlet, the north inlet of Martin Lake, the south inlet of Martin Lake, and Martin Lake outlet. They will use metal bars or screens. At the Typo Lake outlet and the north inlet of Martin Lake, diversion posts in the lake will catch larger debris like floating bogs before they can become entangled in the screens.
The barrier at the outlet of Martin Lake, where a small weir already exists, will have two sets of pivoting bars that allow passage of debris but prevent carp from jumping from the creek into the lake, which has been known to occur during periods of high water.
A final barrier will be at the south inlet to Martin Lake. This barrier is primarily to prevent the trapped carp from moving toward Island Lake, which is in good condition.
The largest project funding source is the Clean Water Land and Legacy Amendment, through the DNR’s Conservation Partners Legacy Grant Program. Those dollars are from the statewide sales tax increase approved by voters in 2008. The Anoka Conservation District has been awarded a $435,754 grant. The Sunrise River Watershed Management Organization, Martin Lakers Association, Metro Conservation Districts and Anoka Conservation District are providing an additional $61,319.
This budget reflects the installation phase. Project planning and design have already been accomplished with funding from the Sunrise River WMO, Metro Conservation Districts and in-kind efforts of the Anoka Conservation District.
Once complete, Linwood Township will own and operate the carp barriers.
“Linwood Township has been great to work with,” said Schurbon. “They’ve listened to their residents and found ways to accomplish their goals despite limited local funding.”
Updates on this project will be posted at www.AnokaSWCD.org