Since it was added to the U.S Fish and Wildlife Services’ endangered species list in November 2018, the candy darter has been the focus of a conservation effort in West Virginia and Virginia along the Kanawha River system – the only known habitat for the brightly colored fish.
The first description of the darter – by American ichthyologists Carl Leavitt Hubbs and Milton Bernhard Trautman – was given in 1932 with the locality reported as Stony Creek in Marlinton.
As part of the conservation effort for the candy darter, the Monongahela National Forest – Marlinton Ranger District has been monitoring streams for fish, as well as improving river habitats which will hopefully increase the number of darters.
“We’ve started investigating a lot of the candy darter habitat on the forest and looking at their habitat usage across the forest and the Greenbrier River,” fisheries biologist Kyle Tasker said. “We’ll be working on the Cranberry soon. There’s not a lot known about the species on the forest as far as habitat usage and what areas it prefers, so we’re just trying to gather a lot of information to help us manage for the species into the future.”
The candy darter is a bottom dwelling species and likes to live among the rocks in the substrate of cold streams.
Tasker said, through the years, the candy darter population has thinned out not from recreation, but from hybridization with the variegate darter which lives downstream of Marlinton.
“Really, populations downstream of Marlinton are pretty much wiped out,” he said. “It’s closely related to the variegate darter which is kind of downstream of Kanawha Falls. What’s affecting the population is they’re hybridizing with the variegate darter.”
In its efforts to save the candy darter, the forest service has focused on watershed improvement and educational materials for the community.
Tasker explained that the Department of Natural Resources manages species, and the forest service manages the habitats.
“We manage for the habitat,” he said. “We are trying to add more large wood to the stream to improve pool occurrences and be able to sort substrates – sorting finer gravels and things like that to hold back sediment.”
When the large wood creates pools, those pools collect highly oxygenated cool water which attracts the darters.
“It increases the complexity of the stream habitat and gives fish a lot more areas to hide from predators,” Tasker said. “We do a lot of habitat reconnection through installing larger crossings at streams, so we’re removing small culverts and putting in larger crossings so brook trout can get into those smaller headwater streams during spawning times.”
Along with making habitats more plentiful and safer for the candy darters, the forest service is also collecting samples from the streams to see where the endangered species is taking up residence.
Through a new technology known as EDNA or Environmental DNA, the forest service can collect water samples from streams and send them to a lab for testing. The water is tested for the DNA of certain species – such as the candy darter.
“Any organism that is in the water is constantly shedding DNA, kind of like we shed our skin,” Tasker explained. We just go to a flowing stream and run five liters of water through a filter and the filter captures any DNA that’s in the water. Then we send it off to a lab, and they analyze it for a particular species that we’re interested in and tell us if that species is available or not.
“It’s pretty cool, because that’s really helpful for understanding aquatic species and how they’re distributed throughout the stream,” he continued. “I think terrestrial species are a little bit easier to find because they’re a lot easier to see sometimes, but the EDNA will give us a good reference – if we’re picking them up in certain stretches of the river or where they may not be present. Then we can focus in our survey efforts.”
There are also ways the community can help with the candy darter rescue initiative. As Tasker explained earlier, the candy darter is disappearing in other parts of the state because they are hybridizing with the variegate darter. One way to stop that is to ensure that non-native species are not introduced into the streams in Pocahontas County.
“We think the variegate darters were introduced into candy darter habitat because of bait bucket transfer,” he said. “That’s when fishermen catch minnows or whatever in a minnow trap and transfer them into candy darter habitat. We’re trying to encourage fishermen – if they are using live bait – to put the bait in the trash if they’re using it in a stream other than where they caught it.
“The key is – if you’re using live bait – only use the bait where you’re capturing it from and don’t transport it,” he continued. “I think a lot of people want to release live fish, but it’s better for the ecosystem to put those bait fish in the trash and not potentially introduce any new species into an area where they’re not found.”
The forest service has also printed special candy darter stickers and coloring books which are available at the district ranger offices.
Efforts to get the candy darter off the endangered species list will continue, especially in Pocahontas County, where it was originally discovered so many years ago.
“It’s really super interesting that we have so many endemic species which are species that are only found in this area of the state, and candy darter is one of those endemics,” Tasker said. “It’s only found in West Virginia and Virginia, so really, you’re losing diversity within the stream. They play this ecological roll in the stream.
“Every fish has its own little niche in the stream and has it’s own role. Candy darters are just another species that do that,” he continued. “Losing them is like losing the biological diversity you have in the streams and reducing the species diversity, which is kind of a bummer when you lose special species like that.”