The Eastern hellbender is the largest salamander in North America, reaching lengths up to 24 inches. They need clean, silt-free streambeds to find prey and avoid predators.

-- Photo Courtesy Of Usda And Freshwaters Illustrated/Dave Herasimtschuk

They haven’t spent 73 days in an underwater habitat, but researchers and volunteers with several organizations in Tennessee have spent hundreds of hours snorkeling their way through Tennessee waterways in order to help preserve aquatic biodiversity.

Conservation Fisheries is a Knoxville-based nonprofit founded in 1986 with the specific purpose to preserve aquatic diversity in the streams and rivers of Tennessee.

Since its inception, the scope of work has grown to include conservation and recovery of rare freshwater fishes using captive propagation, habitat assessment and low impact monitoring techniques.

Over the years, staff and volunteers with Conservation Fisheries have propagated more than 65 nongame fish for recovery and release.

Many of the fish are some of the most imperiled species in the southeastern United States, which sets the organization apart from its peers, as it is the first facility in the Southeast to propagate rare, nongame fish for recovery.

Many fish populations in Tennessee are affected by pollution, habitat destruction or both. Sedimentation and chemical runoff from lawns, fields and parking lots contribute to the reduction of many fish populations in the Southeast.

The construction of dams along the Tennessee River has also contributed to the decline in fish populations because they eliminate free-flowing sections of the river. Dams also contribute to low oxygen conditions on the river bottoms, which can affect bottom-dwelling fish like the eastern hellbender.

The eastern hellbender is a Federal Species of Concern and considered an indicator species because it prefers clean streams and rivers. If both young and adult hellbenders are present in a river or stream, the water quality should be very good. They are known to live up to 30 years in the wild and over 50 years in captivity.

Since 2011, the Tennessee Wildlife Resources Agency (TWRA) has worked to assess the status of hellbenders in Tennessee through surveys and advanced techniques and protocols such as eDNA testing and cryopreservation.

Similar to how forensic scientists use DNA to prove someone was present at a crime scene, biologists can use eDNA to detect the presence of aquatic organisms.

All organisms shed genetic material into their environments through mucus, urine and feces, which is known as environmental DNA. Using this new process, biologists have significantly decreased the labor and money it takes to locate hellbenders by snorkeling through rivers and streams.

In recognition of their outstanding leadership in conservation and efforts to prevent the eastern hellbender and its subspecies from becoming endangered, the TWRA and the Tennessee Hellbender Recovery Partnership were presented with a State Wildlife Action Plan Partnership Award in March of 2013.

Another species of fish well on its way to recovery is the lake sturgeon, which is listed as an endangered fish species in Tennessee.

Considered to be the most primitive surviving bony fish, lake sturgeon can live to be 150 years old. Recognized by their long, shovel-shaped snout, lake sturgeon have a sucker-like mouth that allows it to feed at the river bottom.

In 1998, the Tennessee Aquarium started a statewide effort to establish a self-sustaining population of lake sturgeon in Tennessee and has restored over 125,000 lake sturgeon to the Upper Tennessee Rivers system.

The Saving the Sturgeon program is a partnership with several organizations to reintroduce lake sturgeon and includes the TWRA, U.S. Fish and Wildlife Service, University of Tennessee and Tennessee Valley Authority.

Aquatic species conservation, whether it’s 25 feet under the surface of the sea or 25 inches under the surface of a stream, is an important and growing field of science that helps keep the water we depend on for survival clean.