Trout in Trouble: Habitat Protection Key for Brook Trout in Warming Climate

On May 18, 1939, The Transylvania Times of Brevard published an essay introducing readers to three species of trout found in Western North Carolina streams and rivers: rainbow, brown and the only native species, brook. Author and aquatic biologist Thomas Chamberlain characterized the brook (also called speckled) trout with anthropomorphic flair.

“For the native trout,” Chamberlain wrote, “grand as he is, does not take kindly to the changes made in his home surroundings by civilization.”

Although commercial logging began in WNC in the late 1600s, the scale of the timber harvest grew substantially as railroads connected the region to the coasts, and by the 1890s, local forests were under serious threat. Chamberlain noted that heavy logging had harmed brook trout. He wrote: “The cutting away of timber has caused the larger streams to become warmer. This means less oxygen to breathe and greater susceptibility to disease.”

The habitat loss that Chamberlain bemoaned in 1939 still threatens brook trout today, over 80 years later. 

“Without the habitat, the fish don’t have a chance,” says Jacob Rash, coldwater research coordinator at the N.C. Wildlife Resources Commission.

In an intact habitat, tree cover along riverbanks keeps waters cool in the summer, so brook trout don’t struggle to breathe. Roots hold dirt in place, preventing loads of sediment from washing into streams during storms and clogging the fish’s gills. Undisturbed rock beds provide places to lay eggs, and deep pools offer refuge from predators — each microhabitat serves a different need.

But habitat loss is no longer the only worry for brook trout. Researchers and wildlife managers must now protect the fish, an environmental and cultural symbol of WNC, against the growing threat of climate change. Projected shifts in temperature and precipitation will make the species work harder to find the clean and cold mountain waters it depends on. 

Rash worries that the stress of continued habitat loss and climate change will combine to create unforeseen consequences. “It’s always this cumulative effect of insults that ultimately has an impact,” he says.

In hot water

By 2060, WNC will likely see 10 to 20 more days a year where temperatures reach 95, according to a recent report from the N.C. Institute for Climate Studies. And the impacts won’t be limited to the middle of summer — temperatures will increase throughout the year, with the average annual hottest and coldest temperatures both rising by at least 3 degrees. 

As temperatures climb, so too will humidity, which increases the likelihood of heavy rain. For a species like brook trout, which depends on cold, clear water, these changes could present an existential threat, says Kenneth Kunkel, lead author of the NCICS report.

Climate processes could also exacerbate one another to further increase stress for trout, Kunkel continues. “The warmer temperatures and the greater risk of wildfires are directly linked,” he says. “If you have a dry spell in the future, temperatures are likely to be warmer, which means soil moisture levels will drop and debris on the forest floor will dry out faster.” The dry soil and debris could provide more fuel for wildfires, killing trout with intense heat or toxic ash falling into the streams.

Those whose livelihoods rely on trout have already seen climate effects like extended droughts on their businesses. Galen Kipar, the owner of Asheville Fly Fishing Co. and a fly-fishing guide for 15 years, explains, “We watch the weather like a hawk because it affects our job so much.”

Kipar returns often to the same spots and observes changes in the environment month after month, year after year. In 2016, WNC went through a severe fall drought, and he saw how it changed the streams. Some days, he recalls, the temperatures neared 100, with lower-than-usual water levels.

“Low water levels plus high temperatures is a bad combination for trout. They are basically suffocating,” Kipar says. “With steady fishing pressure matched with that scenario, we saw more fish killed that year.”

Losing ground

Trout have been a staple food for the Eastern Band of Cherokee Indians for centuries, and fishing remains a popular communal activity among tribe members. 

“For so many people in the tribe, their life is on the stream,” says David Rowland, the tribal hatchery fish culturist for the Eastern Band.

The fishing industry is also economically important for the tribe. It’s worth about $25 million annually, according to tribal estimates, which makes it the second-largest industry behind gaming. Much of that revenue comes from fishing permit sales. In 2020, a record number of visitors came to the Qualla Boundary to fish as people sought to get outside during the pandemic.

“It was outrageous,” says Rowland. Born and raised within the Qualla Boundary, Rowland remembers in the old days seeing cars bumper to bumper as tourists came to see the sights. 2020 was a similar scene, and the Eastern Band sold a record number of fishing permits. 

Trout’s economic importance raises the stakes for protecting them from a changing climate. Andrew Sanders is a doctoral candidate at N.C. State University in ecology and evolutionary biology. As a member of the Cherokee Nation of Oklahoma, he wanted to work with the Eastern Band. For one of his courses, he modeled the change in suitable brook trout habitat on Eastern Band territory based on different climate scenarios.

The results were bleak. Using the Intergovernmental Panel on Climate Change’s most optimistic temperature projections, which indicate about 3.8 degrees of warming by 2100, the models predict that brook trout will lose 50% of their habitat in the Qualla Boundary in the next 50 years. The most extreme climate scenario, projecting a nearly 9-degree increase by 2100, would eliminate 92% of suitable brook trout habitat on Eastern Band land by 2070.

Sanders points out that temperature is only one factor determining the brook trout’s future. Increased regional rainfall could cool down the water, and additional tree cover would provide more shade. But conditions also could swing the other way.

“If we expect more canopy loss in the future, these models might turn out to be optimistic,” Sanders notes. “The thing about forest cover is that it can be lost much more quickly than it can be gained.”

Looking at Sanders’ maps of declining suitable habitat, a pattern emerges: As temperatures rise, less livable habitat is available to trout, and the surviving populations become more isolated — further increasing their vulnerability to habitat loss.

Stronger together

Many of the warmer, lower-elevation waters in WNC are stocked primarily with rainbow trout by the state Wildlife Resource Commission and private farms to support the state’s booming sport fishing industry. A study conducted on behalf of the WRC found that the total economic output from fishing in wild trout waters in 2014 was about $60.8 million, supporting over 500 jobs.

Both stocked and wild trout waters are now home to nonnative rainbow and brown trout, whose aggressive behavior can outcompete the native species. Thus, wild brook trout increasingly find themselves relegated to the most remote, high-altitude streams. 

“The more complex a habitat is, the more connected it is, the better the ability the fish has to withstand those impacts,” says Helen Neville, senior scientist at Trout Unlimited.