Great Lakes Fishery Commission

18/09/2026

Changes are coming to the Science Directorate, effective October 1, 2026!

Dr. Andrew Muir, who has directed the Commission's science program for the past 13 years, will move into a newly established Chief Scientist role. Widely recognized as a leading expert on Great Lakes native fish species, Dr. Muir has played a central role in advancing fisheries science and restoration across the region. His new role will expand scientific capacity and foster greater collaboration across programs.

Dr. Dan Zielinski, currently Principal Engineer and Scientist for FishPass, will assume the role of Science Director. Dr. Zielinski brings extensive experience in applied research, engineering, and program leadership through his work on one of the world's most innovative fish passage research initiatives.

Please join us in congratulating Dr. Muir and Dr. Zielinski!

Read the full release here:https://www.glfc.org/pubs/pressrel/2026_Science_Transition.pdf

Photos (L to R): Dr. Andrew Muir, Dr. Dan Zielinski
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16/09/2026

The scenic Bighead River in Southern Ontario is known for its naturalized and self-sustaining steelhead fishery and is frequented by anglers and recreators alike. It is also home to roughly 137,000 invasive sea lamprey larvae.

Fisheries and Oceans Canada Sea Lamprey Control agents will conduct a sea lamprey treatment to remove these invasive species using lampricide (TFM). Lampricide will be applied at a number of sites along 54 km of stream between Thursday, September 17 and Monday, September 21, then flow downstream through the treatment area (see map), reaching the river mouth in Meaford around Thursday, September 24.

Additionally, on Thursday the 17th a small crew will conduct a lentic lampricide treatment at the mouth of the Bighead River within the Meaford Harbour and Marina. Agents will use granular Bayluscide (gB), a lampricide coated onto small granules and applied by spray boat. Once applied, the gB sinks to the riverbed and removes invasive sea lamprey larvae living in the sediment.

Without treatment, many of these sea lamprey larvae would soon become parasites and migrate downstream into Lake Huron, where each will kill up to 18 kg (40 lbs.) of fish by feeding on their blood and body fluids.

Lampricide is applied at low concentrations but may still impact sensitive non-target species such as native lamprey and fish weakened by disease, spawning, or other environmental factors. However, fishing, paddling, and other recreational activities remain safe during treatment and fish are safe for consumption.

For more information about lampricides, visit: www.glfc.org/pubs/factsheets/FACT%204A_HR.pdf

To learn more about the sea lamprey control program, visit: www.glfc.org/pubs/factsheets/FACT%205_all.pdf

Watch the award-winning documentary The Fish Thief, produced by the GLFC and narrated by Oscar winner J.K. Simmons: www.thefishthief.com

15/09/2026

lampricides—chemicals used to kill invasive sea lampreys—are the foundation of the Sea Lamprey Control Program in the Great Lakes? Lampricides target filter-feeding larval sea lampreys in Great Lakes tributaries before they metamorphose and parasitize fish.

Of the approximate 5,300 tributaries to the Great Lakes, about 10% are infested with sea lampreys. Of these, 337 have been treated with lampricides at least once since treatments began in 1958, while approximately 184 tributaries require regular treatments. Because so many systems are infested, it is impossible to treat them all in any given year.

How does the Sea Lamprey Control Program decide which streams to treat each year? Learn more in our fact sheet!

https://glfc.org/pubs/factsheets/Stream-Selection-factsheet.pdf

11/09/2026

Join the GLFC tomorrow from 9am to 3pm at the Muskegon County Fairgrounds for the Sportsmen for Youth Youth Day!

This FREE day of educational family fun will feature a variety of informational booths from sea lampreys, to fishing demonstrations, to live animals from local 4H organizations, and everything in between. Attendees under the age of 17 also receive free lunch and prizes.

We'll see you there!

11/09/2026

The Nottawasaga “Notty” River in Central Ontario, flowing into Georgian Bay of Lake Huron, is known by anglers for its thriving steelhead and salmon runs. It is also home to 101,000 invasive larval sea lamprey.

To remove these invaders, Fisheries and Oceans Canada sea lamprey control agents from Sault Ste. Marie will conduct a lampricide (TFM) treatment in the mainstream as well as the tributaries Boyne River and Innisfil Creek. Treatment will take place from 9/14/26 to 9/15/26, to target larvae currently living in the river as filter feeders.

Last treated in 2021, this effort will cover about 45 km of the river system. Once applied at the uppermost points, the lampricide will take about 2-3 days to travel to the Angus area. As it continues downstream to Wasaga Beach, there will only be trace amounts in the system.

Without treatment, many of these larvae will transform into parasites, migrate to Lake Huron and begin feeding on fish. Each parasitic sea lamprey can kill up to 18 kg (40 lbs.) of fish over its lifetime.

Lampricide is applied in very low concentrations but may still impact sensitive non-target species such as native lamprey and fish weakened by disease, spawning, or other environmental factors. Surveys for non-target and target species will be conducted directly following the treatment.

Fishing, paddling and other recreational activities may continue as usual, as the water is safe for people and pets. Fish caught during treatment remain safe to eat.

For more information about lampricides, visit: www.glfc.org/pubs/factsheets/FACT%204A_HR.pdf

To learn more about the sea lamprey control program, visit: www.glfc.org/pubs/factsheets/FACT%205_all.pdf

Watch the award-winning documentary The Fish Thief, produced by the GLFC and narrated by Oscar winner J.K. Simmons: www.thefishthief.com

Have questions? Drop them in the comments, and we’ll do our best to respond.

10/09/2026

The Pigeon River, which drains into Mullett Lake, part of the Cheboygan River Watershed in Michigan, supports a diverse fishery but currently hosts over 400,000 invasive sea lamprey larvae. Without intervention, these larvae will develop into parasites, migrate downstream, and damage local fish populations.

Starting this weekend, Sept. 12–13, the U.S. Fish and Wildlife Service sea lamprey control team out of Ludington will apply lampricide (TFM) to about 50 miles of the river, including a portion of the West Branch Pigeon River (see map), to target these invasive larvae.

Lampricide will be applied at various points along the river for roughly 12 hours at each site, starting in Otsego County near Ga***rd, taking 3-4 days to flow downstream to Mullett Lake, where it will rapidly dissipate and photodegrade. The treatment will temporarily change the river's color to a yellow or greenish hue and may cause minor unintended nontarget mortality of aquatic organisms that are sensitive or already stressed, but recreational use remains safe.

Learn more about sea lamprey control:https://www.glfc.org/pubs/factsheets/FACT%205_all.pdf

Learn more about lampricide safety:https://www.glfc.org/pubs/factsheets/FACT%204A_HR.pdf

Watch The Fish Thief to learn more about the history of sea lamprey control and the Great Lakes fishery: https://www.thefishthief.com

Have questions? Drop them in the comments, and we’ll do our best to respond promptly.

08/09/2026

that science is the foundation of the sea lamprey control program?

The primary method to control invasive sea lampreys in the Great Lakes is a lampricide called TFM, which kills sea lamprey larvae in streams with little impact on other fish and wildlife populations. Critical to every TFM application is maintaining the lampricide at a specific concentration in streams: let the concentration go too low and TFM will no longer be lethal to sea lampreys; however if the concentration goes too high, TFM could stress other organisms in the stream.

To assess the concentration of TFM during stream applications, treatment crews collect samples at various locations along the treated areas in streams. The stream samples are taken to a mobile laboratory where their TFM concentration is compared to TFM “standards”- vials of TFM at a known concentration. Based on the results of the comparison, treatment crews adjust the amount of TFM applied during the treatment to ensure the in-stream concentration stays at the correct level.

Every year, U.S. Geological Survey (USGS) staff prepare the TFM standards at Hammond Bay Biological Station as part of a larger lampricide quality assurance/quality control program. To prepare the standards, the concentrated TFM supplied by manufacturers is diluted to a specific concentration: the “standard” concentration. The concentration of the standard is confirmed twice using high-performance liquid chromatography (HPLC) in the lab. Then, with remarkable patience, hundreds of vials are filled with the standard. The vials are capped, labeled, wrapped, and eventually transferred to lampricide treatments crews which travel the Great Lakes conducting stream treatments.

If you want to learn more about the lampricides used to kill invasive sea lampreys in the Great Lakes, check out our fact sheet, “Practical Facts about Sea Lamprey Control Treatments”: https://glfc.org/pubs/factsheets/FACT%204A_HR.pdf. And be sure to keep watching for our weekly posts!



📷 A USGS biologist prepares TFM standards at Hammond Bay Biological Station. Credit: Andrea Miehls, GLFC.

06/09/2026

The Great Lakes Fishery Commission is an international organization established by the United States and Canada through the 1954 Convention on Great Lakes Fisheries. The Commission has the responsibility to promote measures that protect and improve the multibillion-dollar Great Lakes fishery, including controlling invasive sea lampreys, advancing science, and facilitating cooperative fishery management among the state, provincial, Tribal, and federal agencies. With today marking the end of our series, we are rounding out our collection with this photo, which highlights both countries in one image. Any thoughts on the location?



Photo credit: Lauren Holbrook, GLFC.

Last week’s photo showcased Mouth of Two Hearted River State Forest Campground, near where the river empties into Lake Superior.

And, since this is our final post of the series for the summer—SPOILER ALERT—this week’s photo was taken below the Blue Water Bridge, which connects Port Huron, Michigan, USA and Sarnia, Ontario, Canada. This spot also marks the southern end of Lake Huron where it meets with the St. Clair River.

Thanks for joining us on our journey this summer!

04/09/2026

Captain Denny Grinold has been one of our GLFC advisors for years, and a new feature from the Great Lakes Fisheries Heritage Trail tells the story of a career shaped by both time on the water and leadership within the profession. His impact reaches well beyond the boat, spanning decades of active involvement in Great Lakes fishery management and a steadfast commitment to keeping this fishery accessible and productive for future generations. The GLFC is proud to count him among its advisors!

Read the full article at www.greatlakesfisheriestrail.org/trail_story/charter-captains/

Their boats work on different lakes, but their stories are deeply connected. That story is shaped by science, grounded in coastal communities, and sustained by captains who have adapted alongside the lakes themselves.

04/09/2026

School’s back in session, and so is the ! We have a great lineup for the rest of 2026, and we hope you can make it. First up: Advancing Cisco Restoration by Caroline Tupper and Christopher Osborne (SUNY Oswego) 🐟

Register now: bit.ly/11092026