Jeff Simmons with crayfish collection

Colossal Crayfish Collection

TVA aquatic biologist Jeff Simmons isn't searching for baseball cards or vinyl records—his passion is crayfish, a vitally important species in the Tennessee River watershed.

JANUARY 20, 2021 — Crayfish, crawdads, mudbugs, ditchbugs, mountain lobsters, or good eats.  No matter what you call it, crayfish are an important bellwether species that Jeff Simmons — a TVA aquatic biologist — studies to measure aquatic health.

The Tennessee Valley is home to one of the most diverse aquatic ecosystems in the world.

People who fish in the region enjoy the plentiful bounty of fish in the area’s waterways, but Simmons encourages people to look deeper.

In addition to being a fish taxonomist, Simmons is a crayfish expert who studies the interesting creatures that live in the Valley’s rivers and streams. Tennessee and Alabama is home to more species of crayfish than anywhere else in the United States.

“Most people think a crayfish is just a crayfish, but in Tennessee alone, we have 96 described species of crayfish,” says Simmons, a member of the TVA team that works with partners across the seven-state region to help protect the Tennessee River system.

Every Jar has a Story

“Many of these species are only found in very limited geographical areas, and unless people know what lives here, they won’t know how to appreciate and protect it,” he says.

Simmons’ 106-species, 3,500-jar crayfish portfolio is the world’s largest collection from the Tennessee River system. This collection contains valuable material that he and other scientists are using to describe new species.



“Research collections such as this are important because if someone in the future wants to know what occurred in a waterbody before it had been altered or polluted, they can glean information from museum collections,” Simmons says.

The TVA biologist studied his craft, prior to joining TVA in 2006, as he worked beside a leading crayfish taxonomist at the North Carolina Museum of Natural Sciences. Today, Simmons is part of the TVA team that tracks and monitors the aquatic health of more than 800 stream sites throughout the Tennessee River system and within the Tennessee and Cumberland River reservoir system.“An important aspect of our work is to help TVA balance power production and environmental protection to ensure that our operations do not harm ecosystems across the region,” he says.

Unwelcome Guests

When Simmons collects crayfish, he catches them, preserves them in alcohol, identifies them to species and then incorporates them into the TVA Crayfish Research Collection. He also maintains a crayfish tissue collection that is being used to determine the relationships of species through genetic analyses.

Simmons works closely with other biologists and researchers in the region. One of his newest partnerships is with a graduate student at Tennessee Tech University who is receiving funding from TVA, Tennessee Wildlife Resources Agency and TTU to assess the biodiversity of a group of crayfishes that represent several undescribed species. One of these species is currently being impacted by an introduced, non-native species of crayfish in eastern parts of the Tennessee River system.



This research is important, because the river system’s biodiversity, some of which is still unknown, is being threatened by non-native crayfish that are being introduced into the waterways — often by people who use crayfish for bait, then dump the remaining bait into the river.

“It is really important for people to understand that species outside of their native range can have catastrophic consequences to native species, including complete extirpation,” Simmons says.

While crayfish may live largely unnoticed in the waterways, they play a prominent role in the overall health of the Tennessee Valley. Not only do they serve as indicators of good water quality, but they also are an important food source for numerous sport fishes and more than 90 terrestrial species.

“At TVA, our mission is to make life better for the people of the Tennessee Valley,” Simmons says. “Our protection of waterways and their ecosystems helps to ensure that we’re preserving the region’s natural heritage for generations to come.”

Read TVA’s 2019 Sustainability Report, and become part of the conversation.