Last week, Nashville Zoo’s ectotherm team in partnership with Tennessee Wildlife Resources Agency and Tennessee State University, waded into the waters of Middle Tennessee to successfully release a total of 24 eastern hellbender salamanders back into the wild. These hellbenders had been raised since 2018 at the Zoo as part of a headstart program, after being collected as eggs from streams in Middle Tennessee.
Hellbender conservation team in waterway preparing to release salamander
This is the third group of headstarted hellbenders to be released back into the wild since the summer of 2021. Based on varying results from the first two releases, the team made changes in preparation for this third round of releases. Some of these changes included giving the hellbenders crayfish (hellbender’s primary food source in the wild) earlier on in the process and changing the date of release to May. Moving the release to May will allow the animals more time to adjust before the hotter months when water levels are lower, and temps are hotter leading to less oxygen in the water.
So far, all the hellbenders from last week’s release are doing well! Our team will be going back to the waterway to track them at least once a week through the fall for wellness checks and to track survivability.
Hellbender being released into a Middle Tennessee Waterway. Photograph by Andrew Zimmerman.
The Need for the Headstart Program
Once widely distributed in the Ozark and Appalachian Mountains, eastern hellbenders are now considered threatened and even endangered in most states. Almost all hellbender populations have been in rapid decline over the last 30 years due to channeling, damming, increased pollution and disease. Eastern hellbenders are listed as a state-endangered species in Tennessee.
With this slow decline over several decades, hellbenders had disappeared from most of their formerly extensive range in Tennessee. The Zoo recognized a need for a headstart program. Headstarting is a strategy that focuses on raising at-risk animals in human care to then be released back into their native habitat in an effort to sustain the wild populations. In 2015, Nashville Zoo collected the first clutch of hellbender eggs for the headstart program
Our hellbender conservation team has made incredible strides in past and present breeding initiatives. Nashville Zoo spearheaded the first successful captive breeding and first controlled breeding of eastern hellbenders with biotechnology in 2012, and the first successful hatching as a result of fertilization with cryopreserved sperm in 2015.
We hope to continue boosting genetically distinct hellbender populations through our established headstart program. A long-term goal is to build a behind-the-scenes, outdoor stream system at the Zoo to breed some animals that were held back from release for this purpose. This would allow researchers to have hellbenders available for headstarting without having to collect eggs in the wild.
A small contribution that nature lovers can do to protect hellbender’s homes and food sources is to not move rocks in or out of rivers or waterways.
Be sure to follow along on our social media for updates on this group of hellbenders that were released! Footage by Andrew Zimmerman.