TENNESSEE VALLEY-Waist-deep in the river, University of Tennessee students pushed into the current. Between them, they carried a clipboard and a long net sideways like a tightrope walker’s balancing pole.
“The first thing to do is get our river legs,” Aaron Coons, Tennessee Valley Authority aquatic zoologist, yelled above the rush of water.
On the riverbank, TVA fisheries biologists Justin Wolbert and Kennedy Irwin and regulatory environmental programs general manager Brian Fowler unpacked tools of their trade – two box-like net traps for catching aquatic insects.
Nearby in the shallows, fisheries biologists Jon Michael Mollish and Maggie Clark taught students how to scoop and flip a seine net.
And upriver, TVA fisheries and aquatic monitoring manager Lyn Williams and fisheries biologist Nick Dew crisscrossed the wide water in a boat.
They were here to do an in-depth checkup of the river’s fish, aquatic insects and habitats – and to teach University of Tennessee students the essentials of sampling.
Along the way, students would see the joys and challenges of being a TVA biologist.
“This is a continuous learning process,” Coons said.
“We’re problem solvers,” Mollish agreed. “We’re understanding the health of the environment based on the resident fish and bug communities. We have such incredible biodiversity here.”
TVA fisheries biologist Jon Michael Mollish, right, teaches University of Tennessee students Jarret Dietzler, Annabelle Bellamy and Haley Gipson how to distinguish features of tiny fish.
TVA fisheries biologist Jon Michael Mollish, right, teaches University of Tennessee students Jarret Dietzler, Annabelle Bellamy and Haley Gipson how to distinguish features of tiny fish.
Power Play
The morning sun glared silver on the water as Mollish gave the wader-clad University of Tennessee students a history primer.
“TVA was first created in 1933 as part of the TVA Act to lift this area out of poverty,” Mollish said.
In addition to bringing electricity to the Valley region, TVA managed resources, planting trees to build back soil for farming and reduce erosion into rivers.
“That’s 40 years pre-EPA, pre-Clean Water Act,” Mollish said. “Environmental stewardship has been a core part of the TVA mission since we began.”
Today, in addition to being habitat for thousands of animal species, the region’s rivers and reservoirs provide drinking water and places to play.
Aquatic health ties to TVA’s mission of stewardship and reliable power because the enterprise can’t run its hydroelectric and other generating plants if water quality is poor, Fowler said.
He would know – he manages regulatory environmental programs and environmental operations which support TVA’s power-generating plants, and his teams work with many federal, state and local environmental regulators across the Valley region.
Today’s Index of Biotic Integrity is one tool TVA uses to understand river life.
Results of the river’s health help TVA accomplish its goals – providing electricity, flood control, recreation, navigation, water quality and water supply to the Valley region.
TVA fisheries biologists monitor about 550 sampling stations along the Tennessee River and its tributaries.
They work with fish, macroinvertebrates and mussels, sharing numerical scores and species data within TVA and with outside partners who work to restore habitats and prevent pollution.
“We have one of the most biodiverse fish assemblages anywhere on planet Earth,” Mollish said. “We have over 280 described species in the Tennessee River system. Y’all are going to see a lot of fish.”
TVA fisheries biologist Justin Wolbert and his team collect aquatic insects and larvae called benthic macroinvertebrates, which tell the story of river health.
TVA fisheries biologist Justin Wolbert and his team collect aquatic insects and larvae called benthic macroinvertebrates, which tell the story of river health.
Fish and Their Food
Monitoring fish and the insects they eat matters because these creatures face many threats.
The biggest one? Sediment.
Soil and silt washed in from land settles in between rocks. It suffocates insects fish eat, blocks the tiny spaces where fish lay eggs and hide and carries pollutants such as pesticides.
Fish then have two choices, Mollish said.
“Big fish may move on, but little fish that can’t migrate may die out. Fish, because they are limited by habitat and pollution sensitivity, make for incredible bioindicators.”
Sampling those bioindicators – and the pollution-sensitive insects they eat – is an all-day affair.
“To be able to detect all the fish species, we’re going to do a sample that will set a baseline,” Coons explained.
If the biologists keep netting new species of fish, the day’s baseline resets.
Each stretching, scooping and thorough checking of the net to record the species within is called an effort.
“Sometimes in a really degraded stream, that could be just 20 sampling efforts,” Coons explained. “In really diverse and complex habitat, that could be 60 or more in a day.”
As the fish crews netted fish from the still pools, shallow sparkling riffles and deep mid-river runs, the aquatic macroinvertebrate crew collected water insects and larvae from root wads, rocks and the silty river bottom.
“Just like fish, bugs are very particular about their habitat types,” Wolbert said.
Using a cylindrical Hess sampler and boxy Surber sampler, the biologists collected quantitative data about the numbers and density of insects and qualitative data to describe the quality of different habitat types.
As Wolbert and Irwin carefully picked through a pan of wiggling aquatic insects, Coons’ voice rang out.
“Now, pull tight,” Coons called to his crew flipping a seine net full of fish. “Tight, tight! Heck yeah! Now we want to start walking. Start pulling it in.”
“Fish are cool,” Wolbert mused. “But you can see everything about a fish when you’re holding in your hand. With bugs, you’ve got to look into the microscope. Some of them have these bizarre spines and nubs on their head. Some of them look like they’ve been left by aliens.”
Aquatic macroinvertebrates can be incredibly difficult to identify to the species level.
For Wolbert and the fish biologists who travel between rivers and reservoirs of TVA’s seven-state service area – which stretches from lowland bayous to high mountain streams and everything in between – that challenge is part of the appeal.
“This work is daunting – the amount of aquatic biodiversity that we’re required to wrap our head around – but it’s challenging and it’s invigorating,” Coons said. “I think it speaks a lot, too, to the expertise that the stream crew at TVA has.”
TVA fisheries biologist Nick Dew and TVA fisheries and aquatic monitoring manager Lyn Williams ferried University of Tennessee students Jenny Crum, Chris Jones, Annabelle Bellamy, Belle Jenkins, Haley Gipson and Jarret Dietzler to this river sampling site.
TVA fisheries biologist Nick Dew and TVA fisheries and aquatic monitoring manager Lyn Williams ferried University of Tennessee students Jenny Crum, Chris Jones, Annabelle Bellamy, Belle Jenkins, Haley Gipson and Jarret Dietzler to this river sampling site.
A Larger Purpose
Late in the day, with the fish and aquatic insect surveys complete, Clark led the university students through the last step: water quality assessment using a high-tech field probe.
Then the boat pulled up, ready to ferry gear and groups two by two back to the opposite bank.
“I was not really aware that TVA did stuff like this until today,” Jarret Dietzler said. “I kind of figured it was just managing the power plants, so it’s cool to get out here.”
Crum had a positive experience, as well.
“Everybody wants to work for TVA,” she said. “It’s fun on the job, but it also has a deeper, larger purpose.”
Coons nodded at the students.
“My favorite part … is getting to work across the whole Tennessee Valley region – the diversity of aquatic life, the diversity of fish, the diversity of landscapes and rivers, just the whole natural world,” he said.
The day of shared river work might lead some of these students to a career in fisheries – and some may make new scientific discoveries of their own.
For student Annabelle Bellamy, this broad-scale study opened up new ideas for study.
“To focus on one animal, that’s beautiful in its own right,” Bellamy said, gesturing to the wide river. “But the whole picture, man, I’m not going to be unhappy with anything I end up with.”
“We’re still learning things new to this day,” Mollish said. “TVA needs young, eager biologists to continue this work.”
Media Release/Susan Ehrenclou
Staff Writer/TVA
