Scuba-diving scientists are on a mission to save the eastern hellbender in the US state of North Carolina.
Work is set to begin to remove Shull’s Mill Dam on the Watauga River in July in order to restore a healthy river ecosystem.
The project will involve the challenging relocation of eastern hellbenders who live in the river near Shull’s Mill Dam to a newly restored habitat downstream before deconstruction begins, with scientists donning scuba gear to dive and collect the hellbenders one by one.
Removing dams to help wildlife
The Watauga River, which starts near Boone, NC and flows out to eastern Tennessee, is home to many aquatic species that have been threatened by human-caused problems, including water quality, pollution, climate change, sedimentation and reduced migratory habitat (which is necessary for reproduction).
With the US’ Infrastructure Investment and Jobs Act 2021, grants were made available for the removal of defunct and unsafe dams across the US to make waterways safer, cleaner and more habitable. Removing Shull’s Mill dam is expected to benefit surrounding wildlife, including the little-known, at-risk species eastern hellbender, a freshwater aquatic salamander, whose nicknames include ‘devil dog’, ‘snot otter’, ‘Allegheny river monster’, ‘grampus’, ‘old lasagna sides’ and ‘lasagna lizard’.
“Removing a dam is like clearing a clogged artery,” says Erin McCombs, project manager for the dam removal and South-east Conservation Director at American Rivers.
“Shull’s Mill Dam is the second dam on the Watauga River to be removed since 2021, and it will greatly improve the entire watershed by reconnecting 35 stream miles. Fish will be able to swim freely, a dangerous public nuisance will be removed, and the waterway will rebuild the riverbanks to make them more resilient to floods and other climate change events.
"The Ward’s Mill dam removal just downstream of Shull’s Mill dam also created a renewed free-flowing river habitat, where we’ll relocate the hellbenders to get them out of harm’s way during deconstruction.”
Eastern hellbender: A vital predator
Listed as a species of special concern in North Carolina, eastern hellbenders are the largest aquatic salamander species in North America, growing up to 29 inches long. They live in rivers from southern New York to northern Georgia and from the central Appalachians to Missouri.
Once widespread across 15 states, nearly 80% of the hellbender population has been lost. The nocturnal amphibians live in underwater caves provided by boulders. In North Carolina, hellbenders are listed as a species of special concern. They’ve been cut off from migrating to other parts of the Watauga River due to a series of dams erected in the last century.
"Hellbenders are the largest aquatic salamander species in North America, growing up to 29 inches long."
“Hellbenders are important because they are apex predators in many rivers, and they’re a bellweather for water quality and habitat quality in our rivers,” says Dr. Mike Gangloff, Appalachian State University Biologist, the Aquatic Biology Lead Researcher for Ward and Shull’s Mill Dam Removals. “We see that sites with the most hellbenders in this river also have the highest diversity of fish and aquatic insects.”
“Hellbenders are an often-misunderstood species,” says Andy Hill, Watagua Riverkeeper at MountainTrue, who are also working on the dam removal project. “Due to land use change, water pollution, loss of habitat, dams and other challenges we've seen a decrease in hellbender populations across their range. If we lose hellbenders, we lose a symbol for the unique biodiversity of the Southern Appalachians.”
How to move a hellbender
The hellbenders are being relocated by scuba divers this week, a novel process, working at night. “There haven’t been a lot of projects where hellbenders have been translocated from dam removal sites,” says Gangloff.
“We’ve classically focused on removing dams from streams with anadromous fish stocks, like salmon, sturgeon and shad. The other cool thing about this project is we’re hoping to re-home them in a section of the river where another dam was recently removed. That site is in a part of the river where we don’t often find hellbenders today but where they were abundant only a few decades ago. Hopefully this translocation will kickstart hellbender recovery in that part of the river.”
Safe relocation of hellbenders is complex and ambitious, the animals found up to 18 feet below the surface in cold, dark, fast-moving water.
“Hellbenders can be challenging to find, especially if they’re under big rocks or in bedrock crevices,” adds Gangloff. “There are a hundred things that could go wrong when you’re working in a river. But the overarching concern is always the weather and how it might affect river levels. Visibility is almost always key to success in the aquatic realm.”
Dam deconstruction is set to start on July 1, dependent on weather, and is likely to take around 3-4 weeks.
"Hopefully this translocation will kickstart hellbender recovery in that part of the river.”
Dam removals are seen as an increasingly important strategy to restore river ecosystems across the United States, Europe and elsewhere, delivering benefits to wildlife, people and businesses. Once Shull’s Mill Dam is removed, it’s set to be a significant economic generator for the region, which is already a trout fishing hotspot in the south-east US, in terms of outdoor recreation and tourism.
A variety of native riparian trees, native grasses and wildflowers will also be planted to aid the river’s health and serve as pollinators that benefit birds, bees and other wildlife.
“The Watauga River is emblematic of river systems across Southern Appalachia,” says Hill. “If it’s happening here, it's everywhere: habitat loss, pollution, deforestation, loss of biodiversity, ecological decline… These two dam removal projects will have incredible benefits to the Watauga River, including aquatic connectivity, cleaner, colder, more oxygenated water that will rejuvenate the ecosystem, flood mitigation, climate resiliency, and more. The benefits are endless, and these projects are possible everywhere.”
Images and video credits: Mountain True
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