Hellbender Salamander Conceived With Cryopreserved Sperm Hatches at Nashville Zoo
January 28, 2016
The Nashville Zoo announced that it has successfully hatched an Eastern Hellbender salamander (Cryptobranchus alleganiensis) using cryopreserved sperm, marking the first time that a salamander was produced using frozen sperm.
“It’s a pretty big deal for the conservation of this species and all amphibians,” said Dale McGinnity, ectotherm curator at the zoo. “This accomplishment means we can collect and preserve milt (seminal fluid containing sperm) from wild populations without removing Hellbenders from their environment. Cryopreserved sperm may remain viable for hundreds to thousands of years when kept at ultra-low temperatures with liquid nitrogen. ”
The progress in reproducing eastern hellbenders has seen milestone achievements in the last several years. In 2011, the St. Louis Zoo had successful natural reproductions of hellbenders in a 32-foot long artificial stream system, and in 2012, the Nashville Zoo hatched two hellbenders via artificial insemination.
Scientists hope that this assisted reproductive technology will help to create a genetically diverse group of hellbender salamanders in an effort to bolster wild populations of the amphibians, which some estimate to be as fewer than 600 individuals throughout their range. The Nashville Zoo has cryoperserved milt from four different watersheds, which they believe is the first gene bank created for any salamander species.
“We really could not have done this alone,” McGinnity said on the Nashville Zoo blog. “Our Zoo’s Amphibian Specialist, Sherri Reinsch, and our Veterinary staff made the project possible. This success would not have been possible without the collaboration other researchers including Dr. Robert Browne, an Australian cryobiologist; Dr. Vance Trudeau, a Canadian endocrinologist; Dr. Joe Greathouse; Dr. Michael Freake; Dr. Brian Miller; Dr. Dalen Agnew; Dr. Carla Carleton; and Dr. Sally Nofs. A special thanks goes to Bill Reeves, the Chief of Biodiversity for the Tennessee Wildlife Resources Agency for the State Wildlife Grant that helped to fund this work which also included statewide surveys, gene banking, disease testing, and genetic work for hellbenders in Tennessee.”
Hellbender salamanders are listed as near threatened on the IUCN Red List of Threatened Species. Their bodies are fairly flat and their skin is folded and wrinkled. They breathe by absorbing oxygen through their skin, which is covered in mucus that is toxic to predators but not humans. The eastern hellbender grows to more than two feet in length and is found in streams in the eastern United States to Mississippi. They are fully aquatic salamanders and don't leave the water. They develop skin lesions when exposed to highly polluted waters. Nocturnal, the hellbender feeds on crayfish, dead fish, insects and other amphibians. They are prey to fish, turtles and snakes. They reach maturity in five to eight years and can live up to about 30 years.