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Change of plans: Novel data from Warnell researchers informs the future of North Georgia Trout

The fish writhed and splashed inside the plastic bucket as Kevin Thomas hustled down the pathway. He ducked off to the side, steadied his load over the water’s edge, and emptied its contents into the chilly waters of Smith Creek.

The rainbow trout shimmied into the deep and disappeared. Although, perhaps, not for long—several anglers out enjoying the crisp, sunny day at Unicoi State Park eyed Thomas and his truck, fresh from a Georgia Department of Natural Resources hatchery, with anticipation.

Thomas’ effort stocking Smith Creek was just a small part of a large, decades-long effort by Georgia Department of Natural Resources to keep the tradition of trout fishing alive across north and west Georgia. Rainbow, brook and brown trout require cold mountain streams for their survival, but in some places, stocking is the only way to keep the fish in the waters.

“In the southeastern United States, Georgia is on the very southern tip of where trout exist,” says Jenna Haag (MS ’19). Her master’s thesis analyzing trout habitat across climate change models is a key component of a report that’s informing Georgia DNR’s updated trout management plan.

The report uses data compiled by Haag, Hailey Yondo (MS ’17) and Warnell faculty Cecil Jennings, Brian Irwin, Nathan Nibbelink and Bynum Boley (BS ’06) to show how warming temperatures can affect trout habitat, as well as fishing preferences for anglers across the region. By understanding habitat in peril alongside how and why anglers drop their lines, it gives fisheries managers a more complete picture of potential issues—and solutions.


Kevin Thomas puts trout int


A supporting role

“I think one of the biggest takeaways for me was the amount of habitat loss that’s possible in North Georgia,” says Haag. “In western Georgia you have a high percentage of anglers fishing for trout, but you may also have the highest percentage of habitat loss. To actually put a number on it and quantify it, I think that was a pretty good takeaway.”

Haag measured the amount of trout habitat that could be lost if temperatures rise an average of 1, 2 or 2.6 degrees Celsius. At the lower end of projections—assuming carbon output dramatically lessens and average temperature increases by 1 degree Celsius—trout habitat in Northeast Georgia decreases by about 25%. But in the most extreme case—and assuming no climate mitigations are put into place—the same area could lose up to 67% of its suitable trout habitat.

These changes could happen on top of what it already a precarious situation for supporting trout. Of Georgia’s 4,000 miles of trout streams, 2,400 miles now offer suitable habitat. Waterways in upper elevations will likely see fewer issues with warming, but lower-elevation streams can see more temperature fluctuations—making trout survival difficult.

This is because rainbow and brown trout prefer waters in the low 60s, while brook trout require slightly colder waters—and are more susceptible to small adjustments in a stream’s temperature. Add to this the fact that most anglers prefer to fish in the summer—when waters reach their warmest—and you have a perfect storm of stressors.

It’s one of many issues addressed on a global scale recently by the American Fisheries Society. In a statement issued by AFS and dozens of partner organizations, scientists from across the globe noted the threats to aquatic resources due to human-caused climate change.

“The caveat here is, we’re already working in a place where it’s a fringe population. And most of that is driven by summer temperatures,” says Nibbelink, associate dean for research and professor of spatial ecology who assisted with data analysis for the DNR report. “Summer temperature squeeze is a good predictor of habitat where you can consistently find trout; those bottlenecks really control reproduction and growth. There’s a lot of thermal refugia, but as you increase temperatures you increase fragmentation and how much refuge there is.”

But, Nibbelink adds, it’s not all doom and gloom. Rather, the report and its scenarios delivered to Georgia DNR offer a road map to counter the effects of a changing climate.

“It helps us know where we can put our stocking efforts, in time and space, both to meet angler preferences and to make sure they’re not just dying when you put them in the water,” adds Nibbelink. “And this kind of study can help us control the effort for stocking when and where it’s suitable. But also because of the angler preferences piece of it, we can take into account what kind of species and what type of impact you are likely to have on angler satisfaction.”


What’s your preference?

The preference of those using the waterways is a key component of the report. While Georgia DNR has included angler preferences in past reports, the spatial component to Warnell’s data adds a new level of detail.

“This will be one of the first studies that shows the spatially explicit overlap of human dimensions with trout habitat,” says Nibbelink. Somewhat ironically, modeling the species response to climate change is not the novel aspect to the report. It’s a common practice by biologists across the country, and Warnell scientists have used similar modeling to examine sea level rise and impacts on amphibians in the Southeast. “But the spatially explicit angle of it is a cool new aspect. It allows us to be smarter and more precise in our management.”

The study’s results are already bearing fruit, as shifts brought on by the COVID-19 pandemic beckoned more people to the outdoors. Before the start of 2020, Georgia’s trends for hunting and fishing licenses were stronger than much of the nation. But since March, demand for fishing licenses in particular has surged. Much of the reasons why—a desire for time outside away from crowds, coupled with a need for more free time to find a stream—are forecasted in the report.

“We have seen an increase in fishing licenses, largely due to the pandemic. And more license sales benefit our aquatic resources,” says Sarah Baker, trout biologist for Georgia DNR.

(Hailey) Yondo and (Cecil) Jennings were able to quantify angler motivations and barriers for fishing in their trout angler survey. Motivations include being in nature and getting away from crowds, while barriers include lack of free time. “Being in nature was one of the few activities people could safely participate in during the pandemic, so we saw an increase in that motivation. And, lack of time was no longer a barrier. Their research supports that those factors likely contributed to increased license sales.”

Whether or not the trends will continue remains to be seen. But since the angler preferences are incorporated into the report, it allows room for growth and change.

“Recognizing the potential trends now can help us invest in the future,” adds Nibbelink. “Maybe we don’t advertise as much about certain areas, or we try to get people to shift to fishing in different times of the year. These predictions can help us maintain fisheries that can survive, persist and serve the needs of anglers effectively. The environment is changing, but this kind of research can help us do a good job of managing our resources.”


New decade, new plan

Georgia DNR last updated its trout management plan in 2001. The report Warnell researchers submitted to Georgia DNR will help inform the new plan, which is awaiting agency review before its final adoption. The proposal adjusts a few of the recommendations for programs compared to its predecessor, says Baker, and ideally will be updated in 10-year intervals going forward.

Smith Creek on a sunny but chilly December dayGeorgia DNR’s plan tackles trout management issues by breaking various topics into programs—think of them as smaller bite-sized chunks—that allow agency professionals to incorporate the Warnell data in more specific ways. Programs with new or renewed focus include wild trout management, habitat conservation and management, managing hatchery-supported waters, public relations and disease monitoring and biosecurity.

The new plan will continue to inform a stocking program that tries to stay in tune with the public’s needs, says Anthony Rabern (BSFR ’81, MS ’84), regional supervisor for Georgia DNR’s trout stocking programs. Of the 1 million or so trout stocked in Georgia waterways every year, he says, a large portion go to waterways in the Chattahoochee National Forest and other public waterways. But they always have an eye and ear out for local adjustments that need to be made.

“We understand the climatic factors that impact our stocking success, and we’ve learned to navigate those factors to maximize the use of our stocked fish,” says Rabern. “In general, we know where people like to fish, so it’s these tried-and-true places—we know where people like to go, we know what streams can support trout.”

But keeping trout alive and anglers happy goes beyond a love of fishing—it’s also an important economic driver. Trout fishing contributes $170 million a year to the Georgia economy, says Jennings, which means balancing the supply of fish with the demand of anglers throughout the year. “For example, if fish are stocked in the springtime and there’s offspring in the summer, many of these will not survive past August,” adds Jennings, who recently retired from his post as unit leader for the USGS Georgia Cooperative Fish and Wildlife Unit. “But if you only stock 10% in the spring and small fisheries in the summer, by September, when the water recovers, they’ll have suitable fish for the rest of the year.”

Jimmy Harris (BSFR ’70), owner of Unicoi Outfitters in Helen, recently opened a second location of his business in Clarkesville. Opening a business in the midst of a pandemic came with its own set of risks, but luckily, the demand for guided fishing trips has made it worthwhile.

Still, Harris says, trout habitat loss is a concern. His is one of many businesses across North Georgia that rely on dollars spent by anglers drawn to the warm weather and cool waters. Any amount of change can affect his business—and he’s already seen some changes.

“We have some private water we take people fishing on, and it’s at a low elevation for a lot of trout streams. It was great until about, well, 15 years ago, when things were getting really warm in the summer,” says Harris. As a result, he and his guides don’t lead trips from June through September, one month more than they used to.

But beyond fewer paid trips for their guides, this also translates into smaller payments to landowners for the use of their streams. These payments help cover property taxes and promote preservation. But if this income goes down, development may make more financial sense.

“You look at your bottom line, as a business, and you say, ‘Wow, this is pretty serious,’” says Harris. “We take a lot of pride in paying the landowners, who have protected that land and kept it from being cut off into smaller lots and being developed. But overall, our stores do less business, our guides make less money and landowners who depend on people fishing on their property to pay their taxes—that’s been reduced.”

But with modeling and solid data, fisheries managers, businesses and residents can rely on a solid plan.

“It’s showing potential scenarios—from what’s possible up to a worst-case—and what you can do with it. How are you doing to prepare? Are you going to do more outreach and tell people it’s going to be a shorter season? Are you only going to stock in certain places because it’s not worth it to stock in others?” says Haag, who is now a fisheries technician for the U.S. Fish and Wildlife Service. “It gives a road map—not necessarily your turn-by-turn directions, but it gives you a point A and point B, and here’s all the different lines you take to get there."

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