Salmon and steelhead are famous for their amazing migrations, but trout and char can pull off some pretty impressive migrations, too.
In the fish business, the term “fluvial” refers to a unique life-history where fish migrate between larger river systems where they spend winters and smaller streams where they spawn, according to Jordan Messner, Idaho Fish and Game fisheries regional manager.
“Sometimes these migrations are quite extraordinary,” Messner said.
Biologists in Idaho documented the remarkable repeat migration of one particular fluvial bull trout, technically a char, despite its common name. In January 2018, this particular bull trout was 12 inches long when it was captured and tagged by Idaho Power biologists in the Hells Canyon section of the Snake River. Small electronic tags were injected into the fish that can later be detected if it is recaptured or swims near a stream with a sensor, Messner said.
The following January, the fish was captured again in the same section of Hells Canyon and measured 16.5 inches.
In late May or early June 2019 that same trout was found in northeast Oregon’s Imnaha River, a tributary to the Snake River in Hells Canyon. Then in July 2019, the fish traveled more than 186 miles to spawn in a small mountain stream in the Salmon River in Central Idaho.
And that’s not the end of the story, Messner said. This bull trout kept going. During the winter of 2020, the fish was recaptured in the same section of the Snake River in Hells Canyon where it had been found in 2019 and was again detected in the Imnaha River in May of this year.
Messner expects the bull trout to soon make its way back to Central Idaho to its mountain spawning grounds, to continue its “remarkable journey.”