Tracking the paths of Coho Salmon in Lake Michigan
Inner ear structures allow researchers to capture history of Great Lakes fish
Many Michiganders enjoy sport fishing or eating tasty salmon, but how well do you know your Great Lakes fish? Kevin Pangle, Ph.D, Director of the CMU Biological Station and the Department of Biology faculty member, has been researching fish in the Great Lakes for over 15 years. More specifically, Coho salmon. He was recently awarded a new grant from the Great Lakes Fishery Trust, “Inferring source-specific Production of adult Coho salmon to Lake Michigan”. This grant will identify the best conditions to produce wild and hatchery Coho salmon.
Pangle’s research examines the balance between the number of Coho salmon produced by natural reproduction and those produced by hatcheries. One fact that surprises people is that
“Many Coho salmon aren’t born in Lake Michigan but rather in nearby streams,” Pangle said. Of the fish produced by natural reproduction, Pangle works to discover the specific stream locations where Coho salmon hatch. This information can be used to understand which streams best support Coho salmon health and a productive, reproducing population.
To answer these questions about Coho salmon, Pangle and his undergraduate and graduate student researchers use otolith chemistry. Otoliths are structures inside a fish’s ear that help balance and hearing. These inner ear structures also store the history of the fish and their prior locations because each body of water has a chemical signature captured by the otolith. “We’ve done a lot of work to figure out what the chemical signature looks like for each of those streams,” Pangle said. Researchers can learn where the largest numbers of Coho salmon are produced, and which streams have the most supportive conditions for the fish.
Pangle appreciates his collaborations with many biologists and state agencies in Michigan that are contributing to this project. Ultimately, Pangle hopes to use his approach with otolith chemistry to inform Michigan fisheries and the public about the reproduction and health of Coho salmon in Lake Michigan so we can all continue to enjoy them for many years to come.
