This coverage is made possible through a partnership between Grist and Interlochen Public Radio in northern Michigan. ​​

Even when they’re young, the characteristic iridescent hues of the Arctic grayling are noticeable at the right angle.

On a brisk morning in September, fish and wildlife biologist Sean Leask counted and measured hundreds of these fish, which were raised at the Grand Traverse Band of Ottawa and Chippewa Indians’ streamside rearing facility, located just outside Traverse City in northern Michigan.

“Some of these might be catchable by the end of next year,” Leask said. “I don’t know what their growth will look like in the wild.”

That’s because Arctic grayling haven’t been seen in Michigan waters for almost a century. By the 1930s, industrial activity like logging and overfishing, along with competition from non-native fish, had decimated their numbers.…