Smelt Update
The 2026 smelt run is over. River temperatures now exceed 60°F in the lower and middle shore but remain in the 50s°F in the upper shore. More information about smelt is provided on our smelt fact sheet.
Management Updates
 Fisheries management in the Great Lakes relies heavily on Sea Lamprey control. Without these annual efforts, Lake Superior's sport, commercial, charter, and tribal fishing opportunities would not exist today. While Minnesota’s North Shore streams generally lack ideal habitat for Sea Lamprey production, specific river systems like the Nemadji and tributary areas near the Lake Superior confluence still produce them. Special thanks to the Great Lakes Fishery Commission, US Fish and Wildlife Service, and Fisheries and Oceans Canada for their ongoing dedication to controlling this harmful invasive species.
U.S. Fish and Wildlife Service News Release May 21, 2026
Marquette Biological Station, 1095 Cornerstone Drive, Marquette, Michigan 49855
FOR IMMEDIATE RELEASE
Contact: Shawn Nowicki, shawn_nowicki@fws.gov, 906-226-1216
Sea lamprey control planned for Lake Superior tributary
U.S. Fish and Wildlife Service (Service) personnel will apply lampricides to tributaries of the Nemadji River (South Fork and Net River, Carlton County) to kill invasive sea lamprey larvae burrowed in the stream bottom. Applications will be conducted between June 2 - 11, 2026, in accordance with State of Minnesota permits. Application dates are tentative and may be changed based upon local weather or stream conditions near the time of treatment.
For more information on sea lamprey control in the Great Lakes visit fws.gov/invasive-sea-lamprey.
Sea lampreys are parasitic fish native to the Atlantic Ocean that invaded the Great Lakes via shipping canals in the early 1900s and remain a major threat to the fishery. They attach to fish with a suction-cup mouth lined with sharp teeth, feed on their body fluids and can kill up to 40 pounds of fish during their parasitic phase. Each spawning pair produces up to 100,000 eggs, with larvae living for years in tributaries before transforming into parasites that migrate to the Great Lakes to prey on host fish.
Infested tributaries must be treated on a regular basis with lampricides to control sea lamprey populations. Failure to reduce sea lamprey larvae populations in streams will result in significant damage to the Great Lakes fishery.
Extensive preparations and precautions are required to deliver a safe and effective stream treatment. Prior to treatment, trained personnel collect data on stream water chemistry and discharge. In addition, they may conduct on-site toxicity tests and streamflow studies using non-toxic dyes that make stream water appear red or green.
Lampricides are carefully metered into the stream for approximately 12 hours and continually analyzed at predetermined sites to ensure proper concentrations are maintained as they move downstream. Applicators are trained and certified by regulatory agencies for aquatic pesticide applications.
The U.S. Environmental Protection Agency and Health Canada Pest Management Regulatory Agency have reviewed human health and environmental safety data for lampricides and concluded that the lampricides pose no unreasonable risk to the general population and the environment when applied at concentrations necessary to control larval sea lampreys. However, as with any pesticide, the public is advised to use discretion and minimize unnecessary exposure. Lampricides are selectively toxic to sea lampreys, but some fish, insects, and broadleaf plants are sensitive. Persons confining bait fish or other organisms in stream water are advised to use an alternate water source because lampricides may cause mortality among aquatic organisms stressed by crowding and handling. Agricultural irrigation must be suspended for 24 hours, during and following treatment.
The sea lamprey control program is contracted through the Great Lakes Fishery Commission (Commission) to the Service and Fisheries and Oceans Canada. Established in 1955 by the U.S. and Canadian governments, the Commission began chemical control of sea lampreys in 1958 as a response to the catastrophic damage of their invasion. Since that time the highly successful program has contributed significantly to the maintenance of the $5.1 billion Great Lakes sport and commercial fisheries. For more information on the Commission, visit www.glfc.org.
The Service works closely with the U.S. Geological Survey to support research, such as the development of supplemental control techniques to be used in areas where lampricides are particularly challenging to apply. In addition, the Service maintains a partnership with the U.S. Army Corps of Engineers in developing a comprehensive barrier strategy for sea lamprey-producing streams, and is investigating barrier design, traps, attractants, and biological control as part of a robust research program administered by the Commission.
For additional information in Canada call 1-800-553-9091. To reach the Marquette Biological Station call 1-906-226-6571 or to reach the Ludington Biological Station call 1-231-843-7300.
For more information or questions about Fisheries in Minnesota waters of Lake Superior, please contact Lake Superior Fisheries Supervisor Cory Goldsworthy at cory.goldsworthy@state.mn.us or 218-302-3268.
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