By Jeff Brooks Gillies and Andy McGlashen
A fish species that vanished from Michigan’s rivers around a century ago could once again swim in the Manistee River.
At least they will if an ongoing study shows the arctic grayling–a timid, glacial relic known for iridescent scales and a sail-like dorsal fin–can survive the predator-laden, dam-warmed waters under consideration. One state fish expert is doubtful.
The Little River Band of Ottawa Indians, along with partners at Michigan Technological University, are studying the river and its tributaries between Hodenpyl Dam near Mesick and Tippy Dam near Wellston.
The work, funded by part of a $200,000 native species restoration grant from the U.S. Fish and Wildlife Service, will consider how the river’s in-stream habitat, water temperatures and other fish species could affect the grayling’s ability to survive there, said Marty Holtgren, a biologist with the tribe.
“We’re not looking at stocking fish within the next couple years,” said Holtgren. “What we’re looking at doing is evaluating the potential of reintroducing those fish.”
Michigan’s grayling were a culturally important resource for the area’s Ottawa Indians until the fish were wiped out around the turn of the 20th century. Logging drives plowed sand over gravel spawning beds. Anglers harvested them by the wagon-load. Stocked exotic brown and rainbow trout ate the grayling’s lunch, and their young.
Grayling disappeared from some streams here by the 1880s. They were gone from the last Michigan stream known to hold them, the Upper Peninsula’s Otter River, by 1936. The species is still widespread in Canada, Alaska and Siberia. A smaller population is hanging on in Montana.
The Michigan Department of Natural Resources tried and failed to bring back grayling as recently as 1991. “Arctic grayling are unlikely to either survive well, or reproduce, in contemporary Michigan rivers,” wrote DNR biologist Andrew Nuhfer in a 1992 report on those efforts (PDF). “They seem to need large, cold, non-fragmented rivers with few competing fish species.”
A matter of degrees
A successful reintroduction “would be the holy grail for fisheries management in Michigan,” according to Mark Tonello, a Cadillac-based DNR fisheries biologist who is not connected to the project. But the stretch of the Manistee River that the tribe and university are studying is unsuitable for the fish, he said.
In a 2004 report (PDF) on the same stretch of the Manistee, Tonello wrote that Hodenpyl Dam warms the main stem enough to hamper brown and rainbow trout reproduction. While it’s difficult to know the exact temperature at which grayling will no longer thrive in a river, the fish are generally understood to need colder water than brown, rainbow and even brook trout.
“You can look at the water temperatures coming out of the dam, and they routinely get above 70 degrees,” Tonello said in an interview. “I’m not a grayling expert. We don’t have grayling in Michigan anymore, so there are no experts here. But from what I know about grayling, those temperatures are going to be lethal.”
But the dam-warmed main stem isn’t the only water the tribe’s biologists are considering. They’re also looking at its smaller, colder tributary streams, including Slagle, Hinton, Peterson and Woodpecker creeks. Holtgren said trout reproduce naturally in these streams, which rarely warm above 65 degrees.
And, despite grayling’s reputation for needing extremely cold water, some grayling streams in Canada and Montana reach temperatures similar to Michigan rivers, he said.
The Manistee has mouths to feed
Grayling also have a reputation for finding themselves in other fish species’ stomachs. Tonello said that stretch of the Manistee is filled with predators like northern pike, smallmouth bass and walleye, “all of which would probably like to eat grayling.”
What’s more, the DNR stocks this section with brown and rainbow trout, which have been accused of complicating restoration by gobbling grayling.
Yet there are sections of the Big Hole River system in Montana where grayling coexist with other trout species, Holtgren said.
If grayling couldn’t survive swimming alongside the Manistee’s trout, the number of fish stocked there could be cut to make way for grayling, Holtgren said.
But that would mean getting rid of fish species that people already like to catch, said Dana Infante, assistant professor of fisheries and wildlife with Michigan State University.
“If it comes to grayling versus these other fish, how do you make a decision as to which rivers should support what? Now that’s the harder part,” she said.
The master’s thesis of a graduate student studying under Infante is one of the reasons the tribe is focusing on this section of the Manistee, Holtrgren said.
Ralph Tingley, a doctoral student in fisheries and wildlife at MSU, combined measurements like size and temperature of the state’s rivers with data on the surrounding landscape, which included factors like human land uses, geology and climate. By comparing those results with what past research suggests makes for a good grayling stream, the project ranked every stream in the state based on its potential to support grayling.
“Our work did not show that that stretch was one of the most optimal places in Michigan,” Infante said. “It’s OK, but not great, by what we did.”
But even though this section wasn’t ranked the highest, that doesn’t necessarily mean that grayling won’t survive there, she said.
“Our picture is an estimate,” she said. “It’s not an exact accounting of what will or will not thrive in an area.”
Despite the potential obstacles of restoring grayling in Michigan, Infante is looking forward to the possibility of catching a grayling in Michigan.
“It’s an exciting endeavor that the tribe is undertaking, and it would be awesome if it worked,” she said. “You’re enhancing a native fishery, which is everybody’s goal.”