What we do!

We reared Hellbenders in the same enclosures while varying food availability and stocking density. We found that as long as food availability was kept at a consistent, minimum percentage compared to Hellbender body weight,  increasing stocking density did not decrease growth. This could help captive-rearing facilities increase their stocking densities, ultimately resulting in more Hellbenders released into the wild.

• Juvenile Hellbenders were reared in raceways that emulate actual streams and standard aquaria.
• Juvenile Hellbenders were released into two different types of soft-release cages: cobble beds vs rock piles.
• Juvenile Hellbenders were released in summer and fall.
• We found that juvenile Hellbenders raised in streamlike raceways that were released into cobble beds in the summer had far greater survival over the first year compared to those with other combinations (e.g., fall x cobble bed x aquaria).

Captive-rearing is essential for Hellbender conservation. Rearing animals from eggs in captivity allows conservationists to release large numbers or relatively large individuals. These individuals presumably have much higher survival than the small 2” larvae would have their first few years in the wild. This increased survival ensures reintroduction efforts advance at a more rapid pace than would otherwise be possible.

Hellbenders in many places have disappeared or reached such low numbers their populations are no longer self-sustaining. Reintroductions are a way to either reestablish populations in areas where they have disappeared but the habitat is still suitable or to help improve an existing population’s ability to reproduce and recruit.

A soft-release is a technique where a release is done in gradual steps rather than immediately releasing animals into their final habitat (hard release). This gives the animals an opportunity to destress and acclimate to their new environment before being fully allowed to disperse into the release site.

We use a two-step process for our releases. The first step involves releasing animals into a temporary holding cage over a cobble bed (Fig X) in their release site where they are exposed to natural conditions but are secure from predators. The final step is removing the temporary holding cage after three days and allowing the animals to disperse from the cobble bed into the surrounding habitat.

Our overall goal is to reestablish self-sustaining Hellbender populations in all historic Hellbender streams that still retain suitable habitat while also working with landowners to implement conservation practices, protect land, and improve water quality throughout those watersheds.

Adult/Juvenile Surveys
Biologists lift large rocks to feel for Hellbenders underneath. Capturing the animals allows us to monitor the health of their populations and the individuals within the population.

Larval Searches
Biologists flip small stones on the riverbed to search for gilled larvae. These surveys allow us to determine if recruitment is taking place, which is an important marker for population health.

Egg Searches
Biologists use snorkels and flashlights to search for guarding males under large boulders. When found, biologists insert a hooked probe under the boulder to search for and collect eggs. These eggs are transported to zoos and other captive-rearing facilities for headstarting and eventual release back into the river.

Habitat Evaluations
Biologists kayak and wade creeks in the historic range for Hellbenders to determine if any are suitable for Hellbender reintroduction. This could be important for establishing new populations and ensuring Hellbenders persist into the future.