GUNTERSVILLE, Ala. (WHNT) -- Tennessee Valley Authority scientists are sending shock waves through Lake Guntersville this week.
TVA fisheries biologist John Justice led a crew of researchers with a pair of electric stun boats to catch bass and other sport fish so the scientists could measure the sizes.
"We can manipulate the current to get the right amount of voltage and amperage that we need to collect the fish. We're very careful not to use more than we need," Justice said.
"We want it to be as harmless and benign to the fish as it can be. It's definitely the best way to sample fish when they're up in the shallow areas of the reservoir in the spring."
The electric current causes the muscles to tense up and inflates the fish's swim bladder, so it floats to the surface. Some fish regain control in just a few seconds, while others need a couple of minutes. By then they're already in a trough on board the boat.
Researchers catch as many fish as possible in 30 minutes. The goal is one per minute.
They document the length and weight of each fish, which goes into data tables used internally for permitting and compliance, technical reports, web summaries.
The information is also available to state and federal agencies, universities, as well as to the general public on the TVA website. You can read summaries here.
"We collect this data to monitor the reservoir. We benchmark it against its long term average and check the general overall health of the fish population," Justice said.
TVA uses the data to see if any changes to river operations have effects on the fish, such as when they started holding water back a little longer in the Spring about a decade ago.
"We make sure that our operations continue to support a fishery like this," Justice said.
"It's important to the economy. It's important to the people that live in the community here."
Many of the surveys are open to the public, and you can ride along on the boats. However, space is limited so contact TVA at (800) 882-5263 to reserve a time slot.