On June 18, Nashville Zoo herpetology team successfully produced thousands of Puerto Rican crested toad tadpoles that were then shipped to Puerto Rico for release. This was the sixth shipment of tadpoles to Puerto Rico. During this time, Zoo staff were able to capture the early stages of development in the eggs for these toads.
Herpetology and veterinary staff started the breeding process by injecting the breeding pair with Amphiplex, an amphibian hormone that stimulates reproduction. These toads are difficult to breed without the help of additional hormones.
After injection, it takes about a day for the females to lay eggs. Within another day, some of the tadpoles had broken free from the clear egg they were developing in and started to swim around. Later that same day, the rest of the tadpoles hatched successfully.
On the third day, some of the tadpoles had already developed eyes and grown in size. About a week later, the tadpoles grew larger and were shipped to Puerto Rico.
Breeding protocols for Puerto Rican crested toads are extremely precise. One breeding event occurs at the Zoo each year, which involved cooling the recommended toads who live in a bio-secure room, from 81°F to 66°F. The toads are then transitioned back to a warmer temperature and placed in a rain chamber that stimulates breeding.
For a decade, Nashville Zoo has been involved with Puerto Rican crested toad conservation. The Zoo first acquired the species in 2008 and had its first successful breeding in 2012. Since, the Zoo sent more than 15,000 tadpoles to Puerto Rico for release. By breeding this species, Nashville Zoo and other zoos across the country are helping keep this endangered species alive in the wild.
Puerto Rican crested toads were the first amphibian to have a Species Survival Plan ®. The species experienced drastic population declines due to habitat loss and the introduction of invasive species. At one point, this critically endangered species was thought to be extinct, but a small wild population has remained in Guanica National Forest. Nashville Zoo, the United States Fish and Wildlife Service (USFWS), Puerto Rican Wildlife Agencies, other zoos and aquariums and local institutions have all contributed to improving the status of Puerto Rican crested toads in the wild.
As the only toad native to Puerto Rico, Puerto Rican crested toads play an important role in their environment. Nashville Zoo plans to continue breeding Puerto Rican crested toads and participating in their SSP.