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By SHAWN SITAR, Fisheries research biologist
Michigan Department of Natural Resources
The oldest known lake trout in the Great Lakes, 62 years old at the time of capture, was recently documented by researchers at the Michigan DNR Marquette Fisheries Research Station.
This fish was collected from Klondike Reef in Lake Superior in the fall of 2023 by a team of intrepid researchers from the DNR, U.S. Fish and Wildlife Service, University of Wisconsin-Milwaukee and Purdue University.
Age is one of most important variables in tracking population health for fish, and this finding indicates that lake trout indeed live long and prosper in Lake Superior.
In March 2024, Dan Traynor, fisheries technician at the Marquette Fisheries Research Station, was working in the lab, processing samples collected in September 2023 at Klondike Reef, a remote offshore area near the Canadian border, 40 miles north of Grand Marais.
Traynor, one of the few experts on the age assessment of lake trout in North America, assigned the age of a humper lake trout collected during the survey. Humper lake trout are one subspecies of the fish found in offshore lake mounts in Lake Superior. They are slow-growing and don’t get very large because they mostly feed on invertebrates.
The fish was female, weighed 2.1 kilograms (4.62 pounds) and was 627 millimeters (24.7 inches) in length. These stats aren’t remarkable – the longest collected by the Marquette Fisheries Research Station was 1,350 millimeters (53.1 inches) and the heaviest collected was 16.1 kilograms (35.5 pounds). The state record for Michigan is 61.5 pounds.
What was remarkable was the lake trout’s age, estimated to be 62 years old – the oldest documented lake trout in the Great Lakes.
This fish, that DNR staff has named “Mary Catherine,” hatched in 1961 (Mary was one of the most common names for babies born that year). When Grandma Mary Catherine hatched, the U.S. president was John F. Kennedy and Yuri Gagarin was the first human to go into outer space.
If fish went to school (high school that is, not just schools of fish), she would have graduated from Klondike Reef High School in the same year as Meg Ryan, Princess Diana and Barack Obama reached that milestone.
Age can be measured in fish with multiple body structures, such as spines. For lake trout, the otolith, or ear stone, is the most reliable indicator of age. The otolith is in the inner ear – humans have them, too – and as the fish grows, so does the otolith.
This growth leaves rings each winter, similar to tree rings, which can then be counted to estimate the fish’s age.
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MDNR Report
Fishing is a cherished pastime for many Michiganders. Bringing along family, friends and young people helps preserve the tradition, but to keep our waters healthy and thriving for the next generation, be sure you aren’t also bringing invasive species to your favorite fishing spots.
Invasive species are those that are not native and whose introduction causes harm, or is likely to cause harm, to Michigan's economy, environment or human health. Most often, invasive species are unintentionally introduced to new places when they become attached to the boats, waders and gear anglers bring on fishing trips.
Michigan’s waters are seeing increased effects from invasive aquatic plants like starry stonewort and European frog-bit, which can choke out habitat and limit fishing access. When these plants get caught on motors, trailers, nets and lines, they can be carried to the next fishing spot. Many aquatic invasive plants can sprout from plant fragments, seeds or tiny buds called turions that can go unnoticed without careful inspection.
Invasive mussels, snails and fish are altering natural food webs in lakes, rivers and streams.
“Zebra mussel larvae, New Zealand mudsnails and didymo cells are hard to see, but they can attach to things like boats, waders and gear,” said Justin Bopp, aquatic invasive species coordinator with the Michigan Department of Natural Resources. “If surfaces are damp, they can survive for several days or even a week. In the same way, water left in bilges, ballast tanks and live wells can carry these tiny organisms and even fish diseases to new locations.”
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MDNR Report
April showers bring May flowers, and spring and summer fish stocking bring fall fishing! This spring and summer, the Michigan DNR stocked a total of 18,958,970 fish that weighed more than 331.5 tons and consisted of 10 different species and one hybrid.
Fish stocking is an important activity to provide both Michigan residents and visitors with quality fishing opportunities. These efforts help bring an estimated $3.9 billion into the state's economy through the sportfishing industry, tourism and related businesses.
To complete the task of stocking, it took 417 stocking trips and 2,345 hours. Crews traveled just over 91,000 miles in 17 specialized stocking trucks to get to the 716 stocking sites. Despite the severe ice storm that affected northern Michigan, which caused a loss of power and transition to backup power for several days at Oden State Fish Hatchery, no fish were lost due to the storm, allowing the DNR to meet its stocking goals.
"We had another excellent spring and summer stocking season that will bring ecological benefits and fishing opportunities to Michigan anglers," said Aaron Switzer, DNR fish production manager. "Thanks to the hard work and dedication of our staff, healthy, high-quality fish were reared and delivered to stocking sites in excellent condition. The numbers produced and stocked hit the targets for most areas."
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MDNR Report
The Michigan DNR has confirmed the presence of invasive red swamp crayfish in an outdoor muskellunge rearing pond at Wolf Lake State Fish Hatchery in Mattawan, Mich.
After stocking muskellunge in Thornapple Lake in Barry County and Lake Hudson in Lenawee County, hatchery staff found the carcasses of two unusual crayfish in the collection basket of Wolf Lake Hatchery Pond 20 (where the fish were reared) after the pond was drained. Crayfish traps were quickly deployed in Pond 20 and two adjacent ponds, resulting in the capture of one live, positively identified red swamp crayfish in Pond 20.
Though native to the southern U.S., red swamp crayfish have been prohibited in Michigan since 2014 and considered invasive in the state because of their ability to aggressively outcompete native crayfish for food and habitat, their high reproductive rate and their destructive burrowing along shorelines that can destabilize banks and infrastructure.
Populations of red swamp crayfish were first detected in Michigan in 2017, with simultaneous discoveries in Sunset Lake in Kalamazoo and a drainage pond in Pontiac. To date, isolated infestations have been confirmed in Kalamazoo, Livingston, Macomb, Oakland, Van Buren and Wayne counties. Infestations are believed to result from the release or escape of aquarium pets, live bait or live crayfish brought to Michigan for crawfish boils.
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MDNR Report
The Michigan DNR, with help from many conservation partners, is halfway through completion of a $5 million grant project to remove 27 stream barriers, including 16 DNR-managed dams. Efforts to date have reconnected more than 140 miles of streams.
Funding for this work was awarded by the National Fish and Wildlife Foundation’s America's Ecosystem Restoration Initiative (formerly the America the Beautiful Challenge), which seeks to conserve and restore aquatic and terrestrial ecosystems, improve resilience to flooding and other threats, and expand community access to nature.
What’s been accomplished so far
The DNR was awarded grant funding in 2022, and work on the project began in June 2023. Since that time, the following components have been completed:
- Crawford County: removal of Hulbert Road Dam.
- Emmet County: replacement of 5 Mile Creek Road-stream crossing and Wycamp Creek Road-stream crossing.
- Jackson County: removal of Portage Creek Trout Pond Dam.
- Luce County: removal of Spring Creek Trout Pond Dam. (Spring Creek, shown above, after dam removal)
- Mackinac County: removal of McAlpine Trout Pond Dam (expected completion September 2025).
- Mecosta County: removal of Altona Dam.
- Oceana County: removal of Marshville Dam.
- Oscoda County: removal of Mio Walleye Pond Dam (expected completion September 2025).