Stan Stamey, a contractor for TVA, nets a large mouth bass while participating in an annual fish count Tuesday morning. The fish are collected using a boat-mounted apparatus that temporarily stuns the fish allowing researchers to weigh, measure, count and examine the fish. Staff Photo by Dan Henry/Chattanooga Times Free Press
Two experienced anglers spent hours fishing around a tree that had fallen into Wolftever Creek — a bass’s favorite hunting ground — with nothing to show for it Monday.
They told Tennessee Valley Authority biologists the area was empty — don’t even bother trying to collect fish population samples from that tree.
After about five minutes of fishing Tuesday, the biologists chuckled to themselves as they caught their 14th fish. It lay on its back, mouth agape as it was pulled from the murky brown water and plopped in a collection tank.
“Look at these. He’s got some big ones,” TVA fisheries biologist Donny Lowery shouted to scientists on another boat as they pulled a net full of exceptionally large fish from the water. “This is a good top, isn’t it?”
Before the day was out, researchers caught — and released — nearly 900 fish as part of an annual sampling intended to give a picture of the overall health of the fish and their environment.
The early conclusion: Chickamauga Lake’s fish population is on the rise.
Samples were particularly large where fallen trees partially were submerged near the creek’s shore.
Bass, the most common of the fish that researchers were trying to count, are ambush feeders with highly sensitive eyes. They tend to hang around an area when they find fallen tree tops that provide shady hiding spots perfect for surprising prey.
“I’m sure these fish were there,” Lowery said of the anglers’ unsuccessful Monday expedition. “A lot of times they think if they can’t catch them, they’re not there. That’s not the case.”
In all fairness to the unsuccessful anglers, TVA scientists had an advantage as they sampled Harrison Bay’s bass and crappie population Tuesday morning. Scientists were dangling electrified cables in front of boats, creating a 5-feet- wide by 9-feet-deep oval charged with enough volts to send a man into cardiac arrest.
“If you were within 10 to 12 feet of the boat, it would not be good,” Lowery said.
Although this technique can be quite successful, Lowery said the average fisherman shouldn’t go attaching a generator to his boat. Electrofishing licenses are strictly controlled by the state, granted only to people such as carefully regulated researchers.
Though deadly to humans, the electricity’s effect is much milder on fish because of their small size. It simply knocks them out for a minute or so, causing them instinctively to fill their swim bladders with air and float on their sides to the water’s surface.
Once the fish were zapped, biologists easily plucked them from all over Wolftever Creek with a net attached to a long pole.
Because the fish are merely knocked unconscious instead of killed, as they were decades ago before less lethal catch methods were developed, biologists return the captured fish to their original homes.
“We try to be user-friendly to the specimens,” Lowery said.
The system worked like a charm. By the end of the day, biologists netted 895 bass and crappie, the largest a 21.5-inch bass weighing 8.9 pounds.
“With fish that size, they stop growing lengthwise and start adding girth. Kind of like us,” TVA fisheries biologist John Justice said.
Biologists still have two more days of testing in the Chickamauga area, but Tuesday’s sample appears to continue the four-year upward trend in the top-of-the-food-chain fish’s populations.
“It’s a good indicator for the aquatic food web,” he said. “If they’re doing well, that tells you everything that supports them is doing well.”
TVA collects data to meet state licensing requirements for its electric plants. Biologists send their data to Tennessee Wildlife Resources Agency, which uses it to supplement its own data and make fish management decisions.
TVA officials have sampled the state’s fish reservoirs annually since 1995 to study population trends. Past experience shows a healthy catch rate comes in at around one fish per minute.
After six hours at Wolftever Creek, TVA scientists had a catch rate of 61.5 fish per hour, up from 2010’s rate of 58.7, indicating a bright future for the area.
“It looks good,” Justice said. “All these lakes are cyclical, but this one is at the top of that right now.”