Partner Project Helps Boulder Darters Rebound

In middle Tennessee, Shoal Creek’s clear waters rise chest-high above a limestone bedrock bottom.

It’s the perfect habitat for boulder darters.

Finger-long females hide clutches of eggs in rock crevices. Males guard the nests, a bulldog look on their tiny fish faces.

Yet few people have seen them.

Endangered boulder darters disappeared from Shoal Creek, which flowed into the Elk and then Tennessee rivers into Alabama, in the 1800s.

Today, experts from Conservation Fisheries Inc., with long-term funding and field support from the Tennessee Valley Authority and other partners, are bringing them back.

They’ve released 14,549 fish here since 2005.

It’s an ongoing conservation success story that TVA’s proud to help write.

“TVA works with partners like Conservation Fisheries and the U.S. Fish and Wildlife Service to protect and improve aquatic biodiversity,” said Shannon O’Quinn, TVA senior water resources specialist in charge of funding Natural Resources projects. “They're doing something very few people in the world can do.”

“It’s pretty cool to reintroduce a fish 140 years after its disappearance,” Bo Baxter, Conservation Fisheries director and senior conservation biologist, said.

A boulder darter ready for release.

Swim Free, Fish

On a spring morning, Baxter and Conservation Fisheries biologist Shannon Murphy drove a cooler of boulder darters that had overwintered in the hatchery to Shoal Creek.

The males’ fins glowed green and the females’ bellies bulged with eggs.

Baxter and Murphy joined members of TVA’s Environment and Sustainability team, which funded the reintroduction and monitors river life across the Valley region.

They stepped into the water cradling four big bags of tagged fish, then waited in the shade of curdled-bark hackberry trees for the fish to acclimate.

“Normally we would be releasing 300 young fish, like we did last fall,” Baxter said. “But this release (of 28 young and 28 adults) is, in my mind, those fish plus however many eggs they carry.”

Murphy and Baxter gave the signal. The fish tipped into the current and swam free.

“It’s full circle,” a smiling Murphy said.

J.R. Shute, co-founder of Conservation Fisheries Inc., and Bo Baxter, current director, show off the rare smoky madtom at Conservation Fisheries Inc. in Knoxville.

Conservation Action

While Shoal Creek and the larger Elk River are perfect boulder darter habitat now, this wasn’t always the case.

“The main tributary (of Shoal Creek) … is Factory Creek,” Baxter said.  “Manufacturing effluent, phosphate mining tailings and a lot of impacts (including raw sewage releases) just wiped out the whole stream."

In the Elk River, boulder darters bred, but they didn’t thrive.

Scientists at Conservation Fisheries discovered why in the 1990s.

Spring and summer releases from TVA’s Tims Ford Dam were too cold and fast for free-floating larvae, Missy Petty, Conservation Fisheries vice president and senior conservation biologist, said.

TVA took action.

“TVA's always been very interested in supporting the restoration of the boulder darter,” Petty said.

J.R. Shute, Conservation Fisheries co-founder, agreed.

“TVA’s always helpful. (They) made adjustments to the way they operated Tims Ford Dam,” Shute said.

“In the early 2000s, TVA took a holistic approach in its entire reservoir portfolio,” Doug White, TVA biological compliance senior manager, said.

To protect fish, TVA stopped generating – letting cold reservoir water through the turbines – from May through October each year.

“At Tims Ford … we let the river naturally warm up and try to reduce the higher flows that are coming out of the turbine impacting the larval fish,” White said.

“It helps the whole warm-water community,” Baxter agreed.

Bo Baxter, director and senior conservation biologist at Conservation Fisheries Inc., explains the filter and tank setup he’s engineered.

Love Shacks and Learning

Seeing the success with the boulder darter today, it’s hard to picture the challenges Conservation Fisheries and its partners faced at the beginning.

“When (renowned ichthyologists) Dr. David Etnier and Dr. Jim Williams described the fish … in 1989 … we knew very little about the biology of these fish,” Baxter said.

So they set out to learn.

The boulder darter is one of dozens of endangered species that Conservation Fisheries has meticulously observed, reared and restored to the wild since the 1980s.

“We really paid attention to where … and how they were spawning,” Shute said. “We’d go to the literature, (and) Pat (Rakes) and I and my wife (Peggy Shute, also a renowned ichthyologist) had done a lot of snorkeling in the creeks.”

They began raising endangered Barrens topminnow and yellowfin and smoky madtoms.

They added blackside dace. Cape Fear shiners. Slender chub. Roanoke logperch. The Okaloosa darter and many other fish over the years.

“We were supposed to be propagating boulder darters, but at that time, they thought the boulder darters were just the rarest fish in the country,” Shute said.

Yet, sifting through the river bottom rocks with snorkels on, they found and began raising the fish.

They used knowledge about the bloodfin darter, a similar and less rare species, to make sure conditions were just right.

“They've thought about it a lot,” Dave Matthews, TVA aquatic zoologist, said. “Conservation Fisheries is the best at what they do with small fish – nobody can match that.”

Today, their biologists are the preeminent experts in raising small native fish – as well as fish food – in biosecure, recirculating systems.

Both in the river and behind the scenes, they’re key collaborators with TVA in restoring the life that belongs in the region’s waters.

At their headquarters in Knoxville, Tennessee, water burbles and filters hum in hundreds of tanks.

Curious fish tap their snouts on the glass, their tank temperatures calibrated to mimic the seasons.

“And all of our lights are on an astronomic timer that mimics the day length at this latitude,” Pat Rakes, Conservation Fisheries co-founder, said.

Through years of observation, biologists learned the "curious quirk" that boulder darters have – they lay their eggs only in tight rock crevices.

“We call these their love shacks,” Murphy said, pointing at slate tiles that create a safe crevice.

“That's what we see with a lot of the rare and threatened species,” Baxter said. “There’s something odd about their reproductive mode that makes them more sensitive.”

Discoveries at Conservation Fisheries saved the boulder darter and may allow it to be downlisted from endangered to threatened. And scientists learned new fish facts.

“No one knew that beautiful green on the male fish existed until we had them in captivity,” Rakes said.

Shannon Murphy, Conservation Fisheries Inc. conservation biologist and volunteer coordinator, shows the "love shacks" she built for successful boulder darter breeding.

A Fish-Filled Future

Back at Shoal Creek, biologists heaved themselves up Shoal Creek’s steep bank, waders streaming water.

“Everybody who’s (involved) here lives for fish,” O’Quinn said. “Not just the boulder darter, but all the rare fish. If CFI wasn't doing this, we'd probably lose these species.”

“We’re the last step in a stream recovery,” Baxter said. “We can't put fish back unless somebody else has recovered the habitat first.”

Healthy habitat depends on TVA and its many partners.

TVA funds riparian buffer and streambank restoration projects with the U.S. Fish and Wildlife Service, Tennessee Wildlife Resources Agency, Natural Resources Conservation Service, Geologic Survey of Alabama and universities such as Tennessee Tech.

And they work with the Natural Resources Conservation Service, farmers and other riverside landowners to reduce soil runoff.

More habitat will open up soon as the Tennessee Wildlife Resources Agency removes Harm’s Mill Dam, a small, non-TVA dam nearby.

“That’s a big deal,” Baxter said. “That’s reconnecting miles and miles of the Elk River.”

“Which would be incredible,” Petty said. “That population can move upstream. … (That’s) where they want to be.”

The crew packed their waders away for the long drive back.

Matt Reed, TVA aquatic zoologist, pointed to the ribbon of blue sky over the river.

“Bald eagles,” he said.

Baxter smiled at the once-endangered birds.

“Species restoration works.”

Photo Gallery

Each fish species at Conservation Fisheries Inc. has its own carefully controlled tank setup. 

Pat Rakes, co-founder of Conservation Fisheries Inc., with his favorite fish, the Barrens topminnow.

Flashy green-finned male and pregnant female boulder darter fish wait in a cooler before they swim free for the first time in Shoal Creek.

Matt Reed, TVA aquatic community ecologist, listens to the background story of bringing the boulder darter back to its home waters.

Shannon Murphy lets a bag of boulder darters acclimate to the river’s water temperature.

Bo Baxter and Shannon O’Quinn release boulder darters into the river.

PHOTO AT TOP OF PAGE: From left to right, TVA’s Shannon O’Quinn, Conservation Fisheries’ Bo Baxter, and TVA’s Matt Reed, Jon Michael Mollish and Jess Wykoff-Carpenter celebrate the release of fish into Shoal Creek.