The rush darter is a “Houdini” among fish – part of it is an escape artist.
A “twisty, restless fish” that leaps easily from your hand, the pinky rush darter appears to move from one small puddle to the next. So says Bankhead National Forest wildlife biologist Allison Cochran, who along with colleague John Moran is working with Alabama Power Environmental Affairs biologists Dylan Shaw and Jeff Baker to study little fish. known.
In 2019, Alabama Power joined United States Forest Service (USFS) biologists in uncovering the mysteries of the rush darter. Biologists have learned a lot about the lives of this species of fish, listed as “endangered” under the Endangered Species Act. Native to Alabama, the rush darter is only found in Jefferson, Etowah, and Winston counties. The studies, among others, are being conducted under an in-kind service agreement between Alabama Power and the USFS associated with the Warrior Hydro license.
The rush darter is found in tributaries of Clear Creek, which flow into Smith Lake in Winston County, but it had never been found in Bankhead National Forest. USFS biologists suspected the rush darter could live in streams running through the 180,000-acre Bankhead National Forest.
“We were pleased with our efforts to find them in the Bankhead, one of the only places the rush darter is found in Winston County,” Shaw said. “It’s a very elusive species – it’s so hard to find it’s very little studied and we’ve been studying it ever since.”
To reach the habitat of the rush darter, the research team travels through public lands, deep in the forest. Beneath the loblolly pines that dominate the wetlands, biologists found the 2-inch-long brownish-yellow fish living in a mere inch of water.
“The rush darter likes to be a little fish in a little pond,” Shaw said with a laugh. “We found fish living in tiny puddles on the forest floor.”
Also present in small tributaries, the rush darter prefers shallow waterways and instinctively avoids fast currents: “It seems to know how to stay away from lakes and rivers, where it will become food for the larger fish ,” Shaw noted. Indeed, the fish was only found well upstream of Smith Lake.
The team is carrying out extensive studies and surveys while searching for all places where the rush darter can live in the Bankhead National Forest, for species management purposes.
“If a listed species is on a certain piece of land, we manage it a little differently than an unlisted species” because the Forest Service actively manages its land, Cochran noted.
Their discoveries became more and more interesting.
“We’ve gone from just finding the species to doing life history studies,” Shaw said. “We are trying to answer questions about the life of this fish. This may include the species’ distribution, how and when it breeds and its behavior while it breeds, and the habitats it uses while breeding or not.
Baker and Shaw monitor water quality and perform dissolved oxygen and temperature tests. Although the company contributes to other cooperative fish-tagging efforts in the state, it does not currently mark rush darter. In future studies, this could be used to help understand where fish move during breeding and non-breeding periods.
“We’re very sensitive to exactly where we found them,” Shaw said. “We won’t take them within 10 feet of where we captured them to avoid any disruption of breeding behavior.”
Using hand nets to capture the tiny fish, they use a photarium – a small plexiglass observation tank with a ruler – to measure, identify and photograph them safely. Baker and Shaw record whether a fish is male or female, whether it is pregnant, and whether the male displays breeding colors. When breeding, the male rush darter takes on a darker, yellow-brown color, and the black dorsal spots on its fins darken.
“They’re not beautifully colored like all the orange, blue, and red darts,” Cochran said. “The rushes are a bit dull and muddy looking, which makes sense as they need to blend in with the leaf litter and vegetation in these wetlands. What’s really cool is that they jump – they’ll surprise you. I blew a few of them from the photarium. This behavior is possibly related to how they move in these true shallow environments, and possibly even related to where they lay their eggs…they might even be able to jump to go upstream.
During the rainy season, when the streams overflow, the fish ride the floodplain waves into small pools where they spawn. On a smaller scale, Baker noted, the rush darter is similar to a salmon making a comeback.
“They are believed to have a strong native sense, going back to the creek where they were born, to do the same to contribute to the next generation,” Baker said. “It’s this strong natal sense that can cause these fish to return to these areas.”
The fish spawn during winter rains, but the team found pregnant rush darters in late summer and even November.
“That’s not what they’re supposed to do, in our view,” Shaw said. “So this fish is kind of breaking the mold.”
Cochran is grateful for the partnership with Alabama Power. She said there was a lot more to learn about the lifespan of the rush darter and how best to protect this endangered species.
“We still have more questions than answers,” Cochran said. “We have a wonderful team, and it has really improved our capacity, our reach and the amount of work we are able to do. It has a huge and incredible impact. We obtain the information needed for use in statewide resource management. We have incredible biodiversity in Alabama and through this study we are raising awareness of the need for quality water, which is essential.
Click to learn more about how Alabama Power helps protect the environment and preserve the state’s rare aquatic species, animals and plants.
(Courtesy of the Alabama Press Center)