Perspectives Online

Meet the Sicklefin. CALS graduate student studies long-undetected western North Carolina fish. By Suzanne Stanard.


Scott Favrot presents a sicklefin redhorse.
Photo courtesy Scott Favrot

The sicklefin redhorse is an unusual fish. It has a curved dorsal fin and a bright red tail. Unlike many of its freshwater companions, this fish swims upstream to spawn, similar to the way coastal fish leave the ocean in pursuit of calmer waters in which to lay eggs. And until recently, the sicklefin redhorse had existed completely under the radar of biologists.

In 1992, Dr. Robert Jenkins, professor of biology at Roanoke College in Virginia, announced his discovery of the sicklefin redhorse, revealing that the world's population of this interesting creature exists almost entirely in western North Carolina waters.

Not much is known about the sicklefin, and with the exception of Jenkins' work, no intensive research has been conducted on the fish - until now.

Dr. Tom Kwak, associate professor of zoology and unit leader of the U.S. Geological Survey, Cooperative Fish and Wildlife Research Unit at N.C. State, along with College of Agriculture and Life Sciences zoology graduate student Scott Favrot, have begun the first-ever ecological study of the sicklefin redhorse.

According to Jenkins' research, sicklefin redhorse live primarily in the Hiwassee and Little Tennessee rivers, relatively small basins along the North Carolina-Tennessee border. The sicklefin shares the water with about five other species of redhorse.

"I think there are a couple of reasons the sicklefin went undetected by early ichthyologists," Kwak said. "First, it occurs in small watersheds that would have been easy to overlook, and second, it could have just been misidentified."

The project's first year was funded by the U.S. Fish and Wildlife Service, the U.S. Geological Survey and the World Wildlife Fund. Along with Jenkins, the N.C. State team is working with Mark Cantrell, a biologist with the U.S. Fish and Wildlife Service who was critical in securing the grant funding. For now, the two-year study will focus on sicklefin in the Hiwassee River and its tributaries.

Kwak and Favrot have two big goals for the study: to define the fish's migratory patterns and to identify its spawning grounds. The first season's work was grueling and the findings surprising.




This photo sequence shows the dam-like barrier — built by Favrot and colleague Hannah Shivley (pictured) &mdash that was used to capture fish that were tagged and released.
Photos courtesy Scott Favrot
"We initially expected that the fish matured in the Hiwassee reservoir and then migrated up into the streams and stayed in the streams," Favrot said. "But, we've found almost the complete opposite to be true. After we tracked the radio-tagged fish for five months, we discovered that they spend the majority of the year in the Hiwassee River, and, in many cases, migrate huge distances to spawn."

One of the most surprising findings was one fish that traveled about 18 miles up the Valley River (a tributary of the Hiwassee), stayed for six weeks, swam back down and then upstream another 10 miles into the Hiwassee River.

Favrot and technician Hannah Shivley, a 2005 graduate of Ferrum College in Virginia, began their work last March. Often working 14-hour days, the pair used two methods to study the sicklefin: radio tracking and two-way resistance board weirs, which are dam-like barriers that capture fish mid-stream as they migrate up or down the river.

By making small incisions in the fish's bellies, they installed radio tracking devices the size of a double-A battery. For 12 hours a day, the devices emitted an audible signal detectable up to 100 yards. Using a receiver in their canoe, the pair paddled up and down stream to pinpoint the locations of the tagged fish and track their day-to-day movements. All this while staying afloat.

"We made good use of bungee cords and plastic totes," Favrot joked. They gathered data on everything from water temperature and velocity to the composition of the riverbed. According to Favrot, the sicklefin tends to hang out in shallow, fast-moving water where the riverbed is rocky.

"We wanted to find out where and when they spawn, and especially what triggers their migration upstream," Favrot explained.

The weirs provided a bigger picture of the river's ecology, trapping all kinds of different fish. Favrot and Shively constructed and installed two weirs on different sections of the Valley River using PVC pipes and netting to create a "wall with a funnel," as Favrot described.

After data collection, the fish were released on the other side of the weir to continue their journeys up or down stream.

"This is a neat, innovative way to study fish migration," Kwak said. "It's been done on the Pacific Coast to track salmon swimming up rivers to spawn, but these methods have really not been used to study migrating fish within a freshwater system."

While the sicklefin population is relatively abundant, Kwak said, its restricted habitat may present problems for the species' survival.

"If some catastrophic event were to occur to this population we're studying [in the Hiwassee and its tributaries], we'd lose half of the sicklefin population in the world," he said. The U.S. Fish and Wildlife Service has proposed the sicklefin redhorse as an endangered species.

Dams in the river system also present a potential obstacle to the species' survival. "We'd like to learn in this study the effect of dams on the sicklefin and how regulatory agencies could operate the dams in more efficient ways to support the fish," Kwak said.

While the team is in the process of finding funds for the second leg of the study, Favrot has high hopes for next season. He'll return to Murphy early in the spring, flip on his receiver, track down the 20 tagged fish and study their every move.

While this work will result in a master's degree, Favrot realizes he is part of something much bigger. He is the first person doing an ecological study on this rare and imperiled species, according to Kwak.

"It's really interesting, finding unexpected results and new, surprising details about this fish," Favrot said.

Kwak adds, "Scientists are being sent to remote parts of the world - to South American rainforests - to study rare species. But, we have this big, seven-pound fish we don't know anything about right here in our backyard. The possibilities for discovery and for helping ensure the long-term survival of this species are exciting."