Laura Lundquist

(Missoula Current) Grant Creek is one of the few streams in the middle Clark Fork River system that still harbors threatened bull trout, so locals are beginning work to improve the stream’s health.

On Friday morning, about 30 people gathered in the Highlander Brewery to learn about native trout, primarily bull trout, and the threats they face in Grant Creek and throughout the Columbia River Basin. They also got an update from Will McDowell, Clark Fork Coalition Stream Restoration Director, on progress being made by the Grant Creek Working Group to restore Grant Creek, particularly the lowest reach.

The Grant Creek Working Group has developed a memorandum of agreement that they’re asking the city of Missoula, Missoula County, the Missoula Conservation District and the Clark Fork Coalition to sign, endorsing a strategy the working group has developed over the past two years to conserve the creek. If all four sign the memorandum, they would begin a planning process in 2024 to lay out five years of restoration work on Grant Creek.

McDowell said the Clark Fork Coalition is in, as is the Missoula Conservation District. Representatives talked to the county commissioners last week, and they’ve indicated they’re likely to sign within the next few weeks. Similarly, talks with city staff have been positive, so  will probably be brought to the city council and the mayor in January for their approval.

“So some of the progress we’ve been aiming for for a while may come to fruition in the coming weeks or a month or so,” McDowell said.

Once the memorandum is signed, the Missoula Conservation District has already received a $20,000 grant from Montana Department of Natural Resources and Conservation, plus smaller grant sums, to develop a conceptual design of the project.

That’s good news to Ladd Knotek and Dan Brewer. Knotek is a fisheries biologist with Fish, Wildlife & Parks who has monitored fish populations in Grant Creek and knows bull trout aren’t doing well. Brewer is the bull trout recovery coordinator for the U.S. Fish and Wildlife Service, and he knows bull trout aren’t doing well anywhere, although the middle stretch of the Clark Fork River, between the Blackfoot and Flathead rivers, is doing better than some.

Knotek explained that Grant Creek has a split personality: it’s great for native trout in the upper reach of its 18-mile length but lousy in the lower reach near Interstate 90.

Grant Creek is born high in the Rattlesnake Wilderness where the water is cold and clear, just what native fish - westslope cutthroat trout, bull trout and sculpin - need. So it’s not surprising that when Knotek does his sampling, he finds primarily westslope cutthroat and bull trout in the upper reach above Snowbowl Road. Even so, only about 30% of the fish are bull trout, mainly because they’re fish predators, while cutthroat trout eat mainly insects.

Grant Creek from the air.
The Grant Creek drainage from the air.

However, around Snowbowl Road, he starts to find nonnative trout, which are better adapted to warmer water and they tolerate sediment from roads, so they tend to outcompete native fish. Bull trout thrive in water cooler than 12 degrees Celsius and can hold their own against nonnative trout. But down near I-90, water temperatures cycle around 15 degrees Celsius.

The farther downstream Knotek samples, the warmer the water gets, the more sediment he finds, and the more nonnative fish he catches. Near I-90, the stream contains mainly brook and brown trout that have moved in from the Clark Fork River.

The lowest section of Grant Creek between I-90 and the Clark Fork River is the worst off, Knotek said, because “it’s basically a ditch.” During the summer, flow can be nonexistent as irrigation diversions draw water out of an increasingly low flow. That creates a barrier for all fish, but especially for bull trout that migrate to upstream spawning areas in the fall.

The result is the bull trout in the upper reaches of Grant Creek no longer migrate so they are smaller - only about a foot long - than the migrating bull trout found in the Clark Fork River. The population is isolated and is starting to show signs of inbreeding - their heterozygosity, a measurement of genetic diversity, is significantly lower than that of bull trout in nearby tributaries such as the Upper Rattlesnake Creek or North Fork of the Blackfoot River. That puts this population at risk so the working group wants to work on ways to keep water in Grant Creek.

Dan Brewer said Grant Creek is better situated than other streams when it comes to trying to save bull trout. A relatively small amount of work and infrastructure is needed, and there’s a local group interested in doing the work.

“Grant Creek is a manageable watershed. In a lot of places, the lift requires Congressional help, we’re talking millions and millions of dollars,” Brewer said. “You have a lot of things going for you, especially the headwaters being relatively roadless.”

Brewer hopes something can be done to save bull trout in Grant Creek because populations are continuing to decline throughout the Columbia River basin. His team just finished a species status assessment that they conduct every five years, analyzing 119 core areas across five states, and the results aren’t promising.

The Fish and Wildlife Service goal is to have bull trout surviving in 25 out of 35 core areas in the Columbia River basin. But based on the status assessment, Brewer said the basin is likely to lose 10, based upon climate and habitat loss.

“If we start at 35, 25 is our minimum, 10 is likely to go away - everything we have today is what we want to keep around,” Brewer said.

In 1998, just before the bull trout was listed in 1999 as threatened under the Endangered Species Act, the Fish and Wildlife Service determined that 14 networks of streams in the middle Clark Fork basin had some bull trout presence. In 2010, when the Service was designating critical habitat, that dropped to 10 networks. But after the recent status assessment, Brewer said that’s probably down to six or seven, including Rattlesnake, Grant, Fish, Cedar and Little Joe creeks.

A species is considered endangered when there’s a chance that it could become extinct without some intervention. A species is designated as threatened when it’s struggling but not enough to be considered endangered.

The question of whether bull trout are nearing an “endangered” listing will be addressed in February, when Fish and Wildlife Service managers will decide what is warranted based on the recent species status assessment, Brewer said.

“If you’re looking at the species range-wide, ‘likely to become extinct’ is a high bar,” Brewer said. “But a lot of our populations across the Columbia headwaters are at very low numbers. We don’t have some highs, some in the middle and some low. Every place is below 50 spawning adults, so I don’t know. We need to double down on our conservation.”

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