The DNR is leading a project at Lock and Dam 5 (LD5) to help protect the Upper Mississippi River from invasive carp. A multi-pronged approach at LD5 and elsewhere on the river is key to supporting the DNR’s goal to slow the spread of invasive carp, minimize their impact, and reduce the likelihood of invasive carp reproducing in Minnesota waters. As outlined in the project’s accomplishment plan, a deterrent that is selective for invasive carp must be installed at Lock and Dam 5 by June 30, 2029 (ML 2024, Ch. 106, Art. 1, Sec. 2, Subd. 5(aa)).
Additional measures will be pursued to create an integrated system to deter and manage invasive carp at this location. The DNR is collaborating with partners to bring their expertise to the LD5 Project, including the U.S. Fish and Wildlife Service (USFWS), U.S. Geological Survey (USGS), Wisconsin Department of Natural Resources, U.S. Army Corps of Engineers (USACE), and U.S. Army Engineer Research and Development Center (ERDC). Funding for this project was provided from the Outdoor Heritage Fund, as appropriated by the Minnesota State Legislature and recommended by the Lessard-Sams Outdoor Heritage Council. Funds are available through June 30. 2029.
Lock and Dam 5 is owned and operated by the USACE for navigation. The lock is located on the Minnesota side of the river, pictured right. Fish can pass through the lock and dam gates at this location. U.S. Army Corps of Engineers photo.
The selective deterrent for invasive carp is planned to be submerged just below the downstream entrance to the lock chamber, indicated by the green arrow. The DNR is coordinating with the USACE St. Paul District on review and permitting for the project. U.S. Army Corps of Engineers photo.
Lock and Dam 5 deterrent
The deterrent planned for the lock at LD5 will be the first selective invasive carp deterrent designed and installed for long-term operation in the United States. The DNR is working closely with USFWS and USGS staff who have worked on deterrent projects, to leverage their expertise and apply lessons learned to LD5. The deterrent will be developed in close coordination with the USACE to ensure compatibility with lock operations. Per the project's appropriation language, a design for the lock deterrent must be completed by June 30, 2026, with completion of construction and installation by June 30, 2029. Ongoing operations and maintenance of the lock deterrent will require additional funding.
A selective, sound-based deterrent for invasive carp is planned for the lock at LD5. Sound-based deterrents are selective for invasive carp, which are more sensitive to noise than native fish. There are only two experimental sound-based deterrents for invasive carp in the United States: the underwater acoustic deterrent system (uADS) that has been temporarily installed at Lock and Dam 19 on the Mississippi River, and the BioAcoustic Fish Fence (BAFF) that is being tested at Barkley Lock and Dam on the Cumberland River in Kentucky. Results from these experimental installations show sound-based deterrents are about 50% effective at preventing passage of invasive carp through the lock, with little to no effects on the native species studied (Brey et al. 2023; Fritts et al. 2023). Unlike the experimental deterrent sites in Iowa and Kentucky, fish can pass through the dam at LD5. This is an important consideration when trying to limit upstream passage of invasive carp.
Above, the uADS being lowered into the lock during installation at Lock and Dam 19. The speakers for this acoustic deterrent are housed in the white boxes along the beam. U.S. Geological Survey photo. Right, the BAFF installation in operation at Barkley Lock and Dam. This deterrent system uses bubbles and lights in addition to sound and is visible at the water surface.
What is the difference between a barrier and a deterrent?
Barriers are physical structures that block movement of all fish, while deterrents discourage fish passage by using stimulus such as sound or bubbles. Sound-based deterrents target invasive carp and are considered “selective deterrents.” A selective approach minimizes impacts to native fish.
Multi-pronged approach to invasive carp
A deterrent at the lock will not reduce passage of invasive carp through the dam gates or remove invasive carp from the water. Sound-based deterrents are also only about 50% effective at preventing passage of invasive carp. Because of these constraints, the lock deterrent is only one piece of the puzzle. As part of this project, the DNR is exploring complementary measures to limit upstream passage of invasive carp and create an integrated system to manage invasive carp at LD5. This is consistent with the DNR’s multi-pronged approach to invasive carp management throughout the state.
‘Trap and sort’ system
A system that would trap and remove invasive carp at this location is being scoped (e.g., ‘trap and sort’). This system could support effectiveness of the lock deterrent by attracting and removing invasive carp that might stack up below LD5. If sorting technologies allowed the system to distinguish between invasive carp and other fish, it could potentially selectively pass fish over the dam and enhance connectivity for native species.
Dam gate deterrents
At LD5, invasive carp can pass through the dam when gates are open during high water, creating ‘open-river’ conditions. Open-river conditions can trigger rapid upstream movement of invasive carp through dams (Fritts et al 2024). The dam at LD5 has six roller gates and 28 tainter gates spanning 1,619 feet, compared to the lock chamber which is 110 feet wide. Deterring passage of invasive carp through the dam gates is key to reducing spread of invasive carp upstream from LD5. However, deterrents for dam gates have not been developed and require future research. Novel deterrent systems for invasive carp at dam gates was identified as a research priority in the Minnesota Aquatic Invasive Species Research Center’s 2025 Request for Research Proposals.
Commercial fishing
The DNR will continue routine tracking and removal of invasive carp below LD5 and elsewhere on the river, to reduce their numbers and limit opportunities for fish to repeatedly challenge the lock deterrent. This commercial fishing work has been funded through federal grant programs, state appropriations, and Environment and Natural Resource Trust Fund awards.
Timeline and updates
June 2024 – Funds awarded for project
The DNR received a $12 million appropriation from the Minnesota Legislature, recommended by the Lessard-Sams Outdoor Heritage Council, for the project ‘Protecting Upper Mississippi River from Invasive Carp.’ The project is taking place at Lock and Dam 5 on the Mississippi River and includes the design, construction and installation of a selective deterrent in the lock chamber. Other activities that support the effectiveness of the lock deterrent are also being considered as funds are available. Project funds are available through June 30, 2029.
July 2024 - Interagency project team formed
The DNR is collaborating with U.S. Fish and Wildlife Service, U.S. Geological Survey, Wisconsin Department of Natural Resources, U.S. Army Corps of Engineers, U.S. Army Engineer Research and Development Center, Upper Sioux Community, and other partners to bring their expertise to bear on the Lock and Dam 5 project. The project team meets monthly to support continued progress on the project.
Members of the interagency project team meeting on site at Lock and Dam 5 to discuss the project.
May 2025 – Monitoring kick-off
Sound-based deterrents are emerging technologies with only two experimental installations at lock and dams in the United States. Monitoring fish movement through Lock and Dam 5 before and after deterrent installation is important to evaluate deterrent effectiveness and detect any impacts to native species. It can also be used to locate areas where fish move at the dam, to site the trap-and-sort and dam gate deterrents. Invasive carp and native fish will be tagged as part of monitoring for this project. The first effort to capture, tag and release fish below Lock and Dam 5 took place in May 2025 and additional tagging will be ongoing.
Minnesota DNR and USFWS staff pulling data from a receiver deployed below Lock and Dam 5. A network of receivers in the river allows us to track fish tagged with acoustic transmitters. Tagging fish to understand passage through the lock and dam is an important component of monitoring and adaptive management for the Lock and Dam 5 project. Photo courtesy of Andrea Fritts, USGS.
June 2025 – Agreement with USACE – ERDC to design lock deterrent
The DNR and the U.S. Army Engineer Research and Development Center (ERDC) entered into a Cooperative Research and Development Agreement (CRADA) to complete the engineering design for the lock deterrent. The DNR is working with ERDC and the USACE St. Paul District under the agreement. An initial task will be completion of a feasibility assessment of the uADS and BAFF deterrent technologies for Lock and Dam 5. The DNR will use this assessment to select the most suitable deterrent option that will then proceed to the design phase.
Citations:
- Brey, M.K., Woodley, C.M., Stanton, J.C., Fritts, A.K., Sholtis, M., Castro-Santos, T., Vallazza, J.M., and Albers, J.L., 2023, Lock 19 underwater acoustic deterrent system study—Interim project update, through 2022: U.S. Geological Survey Open-File Report 2023–1058, 11 p., https://doi.org/10.3133/ofr20231058.
- Fritts, A., Gibson-Reinemer, D., Stanton, J., Mosel, K., Brey, M., Vallazza, J., Appel, D., Faulkner, J., Tompkins, J., Castro-Santos, T., Sholtis, M., Turnpenny, A., Sorensen, P., and Simmonds, R., 2023, Multimodal invasive carp deterrent study at Barkley Lock and Dam—Status update through 2022: U.S. Geological Survey Open-File Report 2023–1051, 7 p., https://doi.org/10.3133/ofr20231051.
- Fritts, M., Gibson-Reinemer, D., Appel, D. et al. Flooding and dam operations facilitate rapid upstream migrations of native and invasive fish species on a regulated large river. Sci Rep 14, 20609 (2024). https://doi.org/10.1038/s41598-024-70076-4.