A bull trout reintroduction in Oregon proves what’s possible

The ambitious effort brings a threatened predator back to the Clackamas watershed.

  • A bull trout.

    David Herasimtschuk/Freshwaters Illustrated
  • Patrick Barry with the Oregon Department of Fish and Wildlife collects adult bull trout from Lake Billy Chinook to translocate to the Clackamas River.

    David Herasimtschuk/Freshwaters Illustrated
  • Researchers with the Oregon Department of Fish and Wildlife implant radio tags into an adult bull trout to help study their movement patterns once they are translocated to the Clackamas.

    David Herasimtschuk/Freshwaters Illustrated
  • Patrick Barry with the Oregon Department of Fish and Wildlife releases an adult bull trout into the Clackamas River.

    David Herasimtschuk/Freshwaters Illustrated
  • Patrick Barry with the Oregon Department of Fish and Wildlife releases juvenile bull trout into a headwater tributary of the Clackamas.

    David Herasimtschuk/Freshwaters Illustrated
  • Researchers with the Oregon Department of Fish and Wildlife record a new bull trout redd in a tributary to the Clackamas River.

    David Herasimtschuk/Freshwaters Illustrated
  • Researchers with the Oregon Department of Fish and Wildlife track translocated bull trout in the Clackamas River.

    David Herasimtschuk/Freshwaters Illustrated
  • A bull trout.

    David Herasimtschuk/Freshwaters Illustrated
 

On a damp October morning, a troop of wader-clad scientists plunged into Pinhead Creek, an icy Oregon stream around 60 miles southeast of Portland, to search for fish nests. Finding those nests, called redds, was no easy task: The same labyrinth of moss-bound logs that makes Pinhead prime fish habitat also makes it a hellacious obstacle course for humans. The crew spent that morning straddling downed cedars, crawling through alder, and getting slapped by the glossy palms of rhododendrons. “Both my feet are soaked,” declared one surveyor, whose boots had sprung leaks. He sounded more cheerful than the situation seemed to warrant.

The struggle, though, only made the discovery of the day’s first redd more rewarding. Chris Allen, a fisheries biologist with the U.S. Fish and Wildlife Service, traced its outline in the streambed with a wading pole, like a conductor guiding an orchestra. “Here’s the pit,” Allen said — where the fish had scooped out a soccer ball-sized depression to deposit its eggs — “and here’s the mound,” where it had heaped the displaced gravel.

I nodded uncertainly. Without narration, the redd would have been invisible. “It’s not an obvious one,” Allen said. “But this is about the right size for a bull trout.”

For the band of researchers canvassing Pinhead Creek, a slim tributary of the Clackamas River, every redd was an auspicious sign. Since 2011, Allen and his colleagues have relocated 1,758 bull trout into the Clackamas watershed, an ambitious — and, in some quarters, controversial — attempt to re-establish this threatened predator to part of its former range. The redd surveys have become an autumn rite, a vital measure of whether the finicky fish are spawning — and whether this landmark program can inspire bull trout reintroduction in other Western rivers.-

A lot, then, was riding on this four-foot-wide patch of pale gravel tucked against a fast riffle. Allen shrugged. “They don’t lay them in textbook places like salmon,” he said. “Bull trout are weird that way.”

Bull trout migrating to spawn in a tributary of the Metolius River.
David Herasimtschuk/Freshwaters Illustrated

Like many salmonids, Salvelinus confluentus had a rough 20th century. Once abundant from the mountains of Montana to the rivers of the Pacific Coast, bull trout were classified as threatened in 1998. The Clackamas, an 80-mile tributary of the Willamette, was a microcosm of the fish’s plight: The river’s bull trout were hammered by decades of overfishing, dam-building, and sediment runoff from logging and road-building. In the 1990s, biologists realized the fish hadn’t been seen in the river since 1963. Surveys confirmed that bull trout were gone.

That could have been the story’s end: Just another local extinction, on a planet where such tragedies are depressingly common. By the mid-2000s, however, the West had entered an era of rewilding. Wolves were again prowling Yellowstone, black-footed ferrets were scarfing down prairie dogs in Wyoming, California condors were swooping over Big Sur. The Clack’s wounds had healed: Fish passage through its dams was improved, and overfishing had been curtailed. In 2007, biologists at the Fish and Wildlife Service, the Forest Service and the Oregon Department of Fish and Wildlife decided the Clackamas was ready for bull trout again.  

Others, however, were less enthusiastic about this apex predator’s comeback. When Allen and his colleagues proposed reintroduction, the National Marine Fisheries Service worried that bull trout would devour enough young salmon and steelhead to damage the Clackamas’ endangered stocks. Anglers — who in some watersheds once received bounties for every bull trout they killed — also balked. “At first I was dead against it,” said Bob Toman, a local fishing guide. “It’s still kind of scary to me.”

To alleviate concerns, the Fish and Wildlife Service agreed to label the reintroduced fish as a “non-essential experimental” population, a designation that allowed for more flexible management and shielded anglers who accidentally harmed bull trout from prosecution. The agency also designed a series of controls, many borrowed from wolf management, that allowed for the removal of individual bull trout, or even the termination of the project, if salmon and steelhead suffered. At last, with the Fisheries Service’s cautious blessing, the reintroduction could begin.

On June 30, 2011, before a cheering crowd, Allen wrestled a gleaming adult bull trout from a blue cooler and into the Clackamas River. The moment was a personal triumph for the scientists involved, one that more than justified years of preparing permits and impact statements. Said Allen, sounding a smidge emotional: “It was the kind of professional highlight that happens only rarely in your career.”

 

Researcher Kristen Harris with the Oregon Department of Fish and Wildlife collects juvenile bull trout in the Metolius River to translocate to the Clackamas River.
David Herasimtschuk/Freshwaters Illustrated

The hard work, however, was just beginning: The agencies had vowed to establish a spawning population of 300 to 500 bull trout by 2030. That presented a challenge for Patrick Barry, the Oregon Fish and Wildlife biologist (now with the Forest Service) who was tasked with capturing juvenile, sub-adult and adult fish via nets and traps from the Metolius River, home of Oregon’s healthiest remaining population. For all their voraciousness, bull trout are delicate: They require frigid water, and the Metolius is three hours from the Clack. Picture technicians in a truckbed on a 90 degree day, frantically adding blocks of ice to a warming transport tank, praying their fish don’t go belly-up. “Boy, we made a lot of ice,” Barry said.

Barry and his crew gradually got better at keeping bull trout alive, and the fish flourished upon release. Radio-tracking suggests that most of the 68 relocated adults and 204 sub-adults have survived and stayed put in their new environs. Even better, bull trout haven’t generally lurked near the dams, where juvenile salmon would be easy prey. Indeed, salmon and steelhead runs have ticked upward since reintroduction began. Though that’s probably a credit to improved dam passage, it also buoys scientists’ hope that bull trout may tilt the Clackamas’ scales in favor of chinook, coho and steelhead. After all, bull trout don’t exclusively eat young salmon: They also feast on mid-level predators, like cutthroat trout and sculpin.

“Without a big boy on the playground, those other fish have been left unchecked,” said Barry. “The Clackamas was already a relatively healthy system, but now it’s a complete system.”

If bull trout indeed stabilize the Clackamas’ food web, it could motivate similar projects elsewhere — and not a moment too soon. Bull trout reintroductions have thus far been few and far between: Besides the Clack, the only significant effort occurred in Oregon’s Middle Fork Willamette River, where biologists have managed to establish a small population of 20 to 30 spawning adults — encouraging progress, but not yet gangbusters success. Meanwhile, S. confluentus’ proclivity for cold water makes it a poster species for the perils of climate change. As temperatures rise, warns Marci Koski, biologist at Fish and Wildlife’s Columbia River Fisheries Program, pockets of warm water may create thermal barriers throughout river basins, leaving some fish stranded. “We need to protect habitat that links populations at risk of being isolated,” Koski told me. “Otherwise, reintroductions and translocations may become more commonly used tools.”

Though the agencies will stop adding bull trout to the Clackamas after 2016, October’s redd survey suggests that the new population stands good long-term odds. By afternoon’s end, we’d counted 10 certain nests; another team saw five more upriver. (Altogether, Allen and his crew found 35 redds in 2014, almost triple the previous year’s tally.) Improbably, the survey’s least-trained member — me — spotted the only actual bull trout: a dark torpedo that hugged the bank as it cruised downriver.

“I have absolutely no doubt that reproduction is happening,” Allen said, satisfied, as he stepped out of his dripping waders. “There are juvenile bull trout swimming around down there. It’s just a matter of catching them.”