Barriers to sea lamprey migration are physical structures placed in tributaries that block access of adult sea lampreys to spawning habitat.
The network of sea lamprey barriers consists of purpose-built barriers as well as numerous dams constructed for other purposes that also serve to block upstream migration of adult sea lampreys. The location and design of purpose-built barriers are determined by a team of experts and are generally designed to block adults while allowing jumping fish to pass safely.
The commission partners with the U.S. Army Corps of Engineers to design and construct physical structures for sea lamprey control.
While purpose-built barriers are inspected on a regular basis and repaired or replaced when necessary to ensure they continue to block adult sea lampreys, many dams constructed for other purposes are being removed to improve fish passage or have been permitted to deteriorate, threatening their ability to block migrating adults. The current network of barriers prevents adults from accessing thousands of miles of habitat, thereby reducing sea lamprey production and saving millions of treatment dollars, but dam removal and deterioration pose an ongoing threat to effective sea lamprey control.
The barriers indicated by have been deemed important to sea lamprey control because they currently block or could be modified to prevent adult sea lampreys from reaching upstream spawning habitats, thereby eliminating or reducing the amount of lampricide control required. In most cases, the barrier is the first blocking structure that a sea lamprey would encounter as it migrates upstream from the lake to complete its life cycle. The determination of importance was made using existing lampricide control and larval sea lamprey distribution information and visual inspections performed on site.
The Great Lakes Fishery Commission requests that any barrier removal or modification project proposed in the Great Lakes basin be reviewed bycontrol agent staff during the project planning process. Project proposals and any other comments or questions regarding sea lamprey barriers can be directed to:
Barrier CoordinatorsJessica Barber (United States)
The purpose of this decision support system:
Select can be used to identify an existing barrier , treatment location , or a virtual barrier created using the "Add Barrier" tool and will show the information available for that feature.
Used to add a virtual barrier to the map. Virtual barriers must be placed within 150m of a river/stream flow line.
Models the distance affected either downstream or upstream by user added virtual barriers.
After using the Add Barrier tool to add barriers and choosing a virtual barrier as a start point, click the Run Trace tool to run the model. A pop-up box will indicate the latitude and longitude coordinates of the virtual barrier and the amount of distance upstream or downstream (based on your selection) affected by adding a barrier to that location.
Clears all virtual barriers
Warning: This step cannot be undone. If you do not want to remove all the virtual barriers then use the Select tool and click on each virtual barrier you want removed individually to choose the Remove this barrier option.
Clears the existing trace that was created by selecting an existing barrier or a model created using the Run Trace tool.
Select Upstream to get the length of the hydrography network in the upstream direction of a modeled barrier or Downstream to get the length of the hydrography network in the downstream direction of a modeled barrier.
Turns the Treatment Layer on or off.
The Treatment Layer provides icons at the mouth of streams that have been treated to reduce sea lamprey populations.
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