Jawbone could lead to non-lethal way to study iconic Great Lakes fish
For decades, the legendary coaster brook trout of Lake Superior has captured the imagination of anglers across the Great Lakes region. Revered for their size, beauty, and rarity, these fish remain one of Michigan’s most iconic native species — yet scientists still know surprisingly little about them.
Researchers at Central Michigan University are hoping to change that.
“Coaster brook trout may be Michigan’s state fish, but there’s still a lot we don’t fully understand,” said Kevin Pangle. “We’re trying to learn more about how they live, migrate, and survive.”
Coaster brook trout are genetically identical to inland brook trout, but unlike their river-bound relatives, coasters spend part of their lives roaming the cold waters of Lake Superior before returning to tributary streams. Scientists are still searching for answers as to why some brook trout migrate into the lake while others remain in inland streams their entire lives.
Another mystery is why certain streams support coaster populations while neighboring systems do not.
Graduate student Sara Gillette is working on a project that could help researchers study coaster brook trout without killing them in the process.
Traditionally, scientists examine tiny bones found in a trout’s inner ear — called otoliths — to study the fish’s life history. Much like tree rings, these structures contain chemical records that reveal where the fish has lived throughout its life. The problem is that removing those bones requires sacrificing the fish.
Gillette’s research is exploring whether similar information can be gathered from a portion of the trout’s upper jaw instead. If successful, the technique could allow researchers to study coaster populations while keeping the fish alive.
Samples collected from coaster brook trout are turned into microscope slides and analyzed using specialized equipment that records hundreds of thousands of measurements from each specimen. The work produces enormous amounts of data, but researchers say modern fisheries science increasingly depends on advanced data analysis and technology.
The study is part of a larger collaborative effort between agencies and researchers in Michigan, Wisconsin, Minnesota, and Ontario aimed at restoring coaster brook trout populations throughout Lake Superior.
Once abundant across the region, coaster brook trout declined dramatically due to overfishing, habitat degradation, and environmental pressures. Today, conservationists and fisheries biologists are working to better understand the species in hopes of rebuilding sustainable populations.
Because of their unique life history and almost mythical reputation among anglers, coaster brook trout remain one of the most sought-after native fish in the Great Lakes.
“Anglers are incredibly passionate about coaster brook trout,” Pangle said. “There’s a lot of excitement surrounding the opportunity to catch one.”
For Gillette, the project is also helping shape a future career in fisheries biology. She began the research as an undergraduate capstone project and continues the work through CMU’s accelerated graduate degree program, which allows students to earn a master’s degree in five years.
Researchers say demand for fisheries biologists remains strong across tribal, state, and federal agencies — good news for the next generation of conservation scientists working to protect one of Michigan’s most treasured fish.
Source: Central Michigan University – CMU Researcher Studies Safer Way to Learn About Coaster Brook Trout