Trout are dying in the lower Saluda River. Scientists are trying to figure out why.

Michael Sims moved into a home off Corley MIll Road six years ago, hoping he’d found the right spot to raise his family on a peaceful stretch of the Saluda River.

But there was another reason for his interest in living there. The new house gave him access to a waterway that would help satisfy his passion for trout fishing, a sport he’s loved for much of his life.

For a while, Sims hooked big trout in the lower Saluda River. Now, they are so scarce Sims isn’t doing any trout fishing this fall — and state wildlife officials are trying to understand why trout populations are suffering.

Since 2017, the S.C. Department of Natural Resources has found that fewer rainbow and brown trout the agency stocks in the river are living past one year, a pattern that is hurting the once-robust fishery near Columbia.

This year, biologists did not find any brown trout that had lived past one year, and the findings for rainbow trout weren’t much better. It’s the worst year for long-lived trout in at least nine years, state officials say.

Trout that live more than a year after stocking, known as holdovers, are important because they spawn in the lower Saluda — which boosts the trout population — and they grow to sizes that lure fishermen to the river’s rocky shores.

In turn, that helps the economy, according to the DNR.

Statewide, 40,000 anglers fish for trout in South Carolina each year, collectively pumping $14 million annually into the economy from the mountains to Columbia., the state wildlife agency says.

An estimated 50 percent of the anglers fishing on the lower Saluda are seeking to hook trout, said Jason Bettinger, a state wildlife department official knowledgeable about trout in the Columbia area.

That’s part of the reason the Department of Natural Resources pays attention to rivers that can support trout by stocking about 500,000 of the fish every year, including about 30,000 browns and rainbows in the lower Saluda.

Unfortunately, DNR studies “indicate that the abundance of holdover fish for both species has steadily declined since 2017, with the largest reduction in abundance occurring this year,’’ Bettinger said.

Sims said that’s disheartening.

“The most frustrating thing is we had such a unique and thriving fishery up until 2017,’’ Sims said. “It will take several years to build it back.’’

The natural resources agency is expected to stock the lower Saluda again next month, and that will give anglers fish to catch — at least for a while. But without some holdover trout living past one year, the fishery will suffer in 2022 as it has recently.

What’s causing the Saluda River trout problem is a bit of a mystery, although biologists have some clues.

The DNR suspects the falling number of stocked trout that live through the year is related to higher river flows, which have made life difficult for a species that needs clear, chilly water and plenty of oxygen.

Large volumes of water released through the Lake Murray dam robbed parts of the lower Saluda of oxygen at one point in 2020. Overall since 2017, heavy rains have swollen and churned the lower Saluda so much that many trout the DNR stocks every winter and spring may be too stunned to survive, Bettinger said.

“I do not know the answer 100 percent, but I have my preliminary conclusions,’’ he said,

Bettinger said he has no evidence pollution or overly aggressive anglers are shrinking the population overall.

While the state has had no reports of fish kills on the river since the fall of 2020, Bettinger said that indicates only that the fish are not all dying at the same time. Other fish may be eating some of the trout, he said.

The recent trend is a big change from just a few years ago.

Until 2017, biologists had discovered that trout stocked in the Saluda were beginning to survive well after they were brought there from the agency’s Oconee County hatchery and dumped in the water.

DNR studies found 167 trout stocked in the river had lived past one year from 2012 to 2014.

Some of the fish were large by trout standards.

One brown trout, for instance, weighed nearly 7 pounds and was 24 inches long. The average brown trout is 14 to 24 inches in some parts of the country. The South Carolina wildlife departments lists a smaller average size, about 8 inches to 10 inches.

A rainbow trout caught by South Carolina biologists had reached 22 inches long. Nationally, the average mature rainbow is about 16 inches, the U.S. Fish and Wildlife Service says. The DNR says the average rainbow trout in South Carolina is 7 inches to 8 inches long.

Biologists also were finding signs that trout had begun to reproduce. Tiny trout that were smaller than any stocked in the water were showing up, strongly indicating the big trout were spawning and establishing a wild population.

Although state officials never expected wild trout would replace the need to stock fish in the lower Saluda River, reproduction had made the fishery more healthy.

Malcolm Leaphart, who has fished for trout in the lower Saluda since the 1970s, said the presence of long-lived, wild trout reassures people the water is clean and healthy enough for a variety of activities, ranging from kayaking to swimming.

“It’s a quality of life issue,’’ he said., noting that having holdover fish spawning in the river “was a great success story. But it’s a problem now.’’

Lowcountry meets mountains

Questions about the future of trout in the lower Saluda River once were non-existent because the fish aren’t natural to the waterway.

The Saluda near Columbia was like other rivers in central South Carolina, a warm waterway meandering through the lower Piedmont toward the coastal plain. But after Lake Murray was built in the late 1920s, frigid water from the bottom of the deep reservoir was regularly released through the dam, causing the temperature of the lower Saluda to drop enough to support trout, a cold water species.

South Carolina wildlife officials then began stocking the river with mountain trout, creating a different kind of fishery in the steamy central part of the state. Only one other spot outside the mountains — an area below the Lake Hartwell dam on the Georgia border — supports a cold water trout fishery in South Carolina.

Today, the presence of trout in the lower Saluda makes for an interesting connection between the mountains and the coastal plain.

It’s the only place in South Carolina where visitors can find Spanish moss, a lowcountry plant species, hanging from trees along a river that contains trout, a species from the southern Appalachians.

Trout like those stocked in the Saluda are predators that feed on insects, crayfish, worms and other organisms in chilly streams across the United States.

Rainbow trout, characterized by swaths of red and pink on their sides, are the fifth most popular game fish in North America, according to the U.S. Fish and Wildlife Service. Many anglers like catching them because rainbows often jump after they are hooked.

Rainbows prefer gravel bottom streams with natural cover and water with temperatures of 55-60 degrees, although they can tolerate temperatures of up to 70 degrees, the service says. Temperatures in the lower Saluda are largely below 70 degrees, but have risen above that for brief periods in the summer, federal data show.

Brown trout, which often have a yellowish hue and are less colorful than rainbows, were brought to the U.S. in the late 1800s from Europe and are more closely related to salmon than other trout, according to the South Carolina wildlife department and “Trout of North America, the Complete Guide.”

Brown trout can live in cloudier, silt-filled streams better than rainbows, often competing with other fish more effectively than rainbows, the S.C. Department of Natural Resources says. The DNR says skilled fishermen often prefer brown trout because they are larger than rainbows and “are the most difficult of all trout to catch.’’

Jake Howard, a local fishing guide, knows all about trout in the lower Saluda. The river has provided him with a steady source of income for years.

Trout, however, have been so hard to find the last three autumns that the number of trips he guides has plummeted. The reduction in guided fishing trips has cost him at least $5,000 annually since 2018, he said.

“That was the best time, in my opinion, to go for the big fish,’’ he said of the fall trout season.

Howard questions whether the operation of the Lake Murray dam by Dominion Energy, the Virginia headquartered utility that acquired SCE&G a few years ago, is hurting the river and trout populations. He’s concerned that dam operations are hurting oxygen levels and water temperatures.

“They have not done anything to convince me they are doing it right,’’ Howard said.

The power company disagrees.

“We have a deep appreciation for the environment and are always working hard to reduce our impact,’’ Dominion spokesman Matt Long said in an email.

Long said oxygen in the water met the state standards “100 percent of the time’’ during the first nine months of 2021. During the past decade, the power company has maintained oxygen levels within the state standard more than 95 percent of the time, he said.

The power company, as part its effort to secure a new federal license for the Lake Murray dam, has plans to install new turbines at the dam that have “more effective aeration capability,’’ Long said.

It’s unknown when the upgrades will occur because the federal government hasn’t made a final decision on the license renewal plan after 13 years of discussion.

If the upgrades had been in place in late 2020, they might have saved trout and other fish in the lower Saluda River.

Three days without air

For three days in September of last year, dissolved oxygen levels were recorded at near zero in the lower Saluda.

Dominion Energy released large volumes of water through the Lake Murray dam and into the Saluda River in anticipation of Hurricane Sally, which was expected to drench much of South Carolina. The idea was to keep lake levels low enough to withstand the expected rain.

Unfortunately for fish in the lower Saluda, existing equipment at the dam that is used to keep oxygen in the water isn’t as effective when large volumes are pushed through the huge superstructure. At the same time, one of the devices used to aerate the water malfunctioned.

“I’m pretty sure that resulted in some trout mortality,’’ Bettinger said.

Unlike catfish and some other species, trout are among fish that need high levels of oxygen in the water to survive. Water released from Lake Murray to the river often has low oxygen levels, meaning air must be added to the water.

As it turns out, Dominion’s decision to release a lot of water may not have been necessary. The rainfall “didn’t materialize as it was forecast,’’ Dominion’s Raymond Ammarell said at a Trout Unlimited meeting earlier this year.

Bettinger said, however, that the water release in 2020 doesn’t account for the overall trend since 2017. The bigger question is why fish have had trouble living as long, overall, for each of the past five years.

Higher, rain-induced river levels could be too much of a shock for the hatchery-raised fish when they are deposited by the DNR into the river each winter and spring, he said.

Essentially, the fish go from a cushy, calm environment where they are well fed at the Oconee County hatchery to a wild river, where they must swim hard to find resting places, find food and avoid predators, Bettinger said.

“They’re not going to do as well when they are thrown in those high flows,’’ Bettinger said.

Sims, the fisherman who moved to Corley Mill Road, said he doesn’t know all the reasons for the problem, but there’s no doubt that trout are suffering.

“I just know the fishery is being hurt,’’ he said. “It’s not being sustained, when before it was thriving and growing. Something changed, and it’s pretty clear we need to do something to get it back to where it was before.’’