Oakland Zoo Conduct 18th Release of Endangered Frogs

Posted By : The Animal Facts Editorial Team

Date: July 31, 2021 10:00 am

 Each yellow-legged frog is transported to the release site in their own container labeled with their PIT tag number and sex.

Photo Credit: Oakland Zoo

Oakland Zoo have released 33 Sierra Nevada yellow-legged frogs back to the wild in Sequoia Kings Canyon National Park after they were raised over the last two years at the zoo. The important cargo was moved by helicopter to the release site.

Each year the zoo conduct releases of yellow-legged frogs across 3 different species. With this release they have helped boost the population of these threatened animals by a total of 626 in 18 releases.

This is further bolstered by releases conducted by the San Francisco Zoo & Gardens.

Some of the Sierra Nevada yellow-legged frogs in the Oakland Zoo Biodiversity Building

Photo Credit: Oakland Zoo

Sierra Nevada yellow-legged frogs are threatened in the wild by the introduction of non-native fish and the chytrid fungus which is devastating frog populations across the globe. The fungus means frogs struggle to regulate water and salt intakes eventually leading to cardiac arrest.

A large amount of work goes in to preparing the frogs for return to the wild. Initially tadpoles are collected from the wild and brought to the zoo where they receive an optimal environment to undertake their life cycle.

As they grow they receive an anti-fungal chytrid treatment which will work to inoculate these animals against the virus when they return to the wild. After this they receive a pit-tag which is similar to a microchip you may give to your dog and undergo a final swab for chytrid. If all is clear they can return to the wild.

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Oakland Zoo dedicate eleven of their staff, interns and volunteers to work every day of the year on the three yellow-legged frog programs ad the zoo’s Puerto Rican crested toad program.

“What makes this effort so worthwhile is knowing that all of the hard work and countless hours we’ve invested here at the Zoo gives these frogs the best possible head start in hopefully ensuring that their populations in the wild will survive,” says Samantha Sammons, Conservation Biologist at Oakland Zoo.

The primary goal of these programs is to release healthy frogs, large enough to avoid predation, and with an immune response to chytrid disease, thus increasing the breeding population to help re-stabilize the species population.

“The reintroduction efforts we have recently been conducting are one of the few tools currently available to try to recover these species. They require close collaboration by multiple partners, and the expertise provided by cooperating zoos, like Oakland Zoo, has been essential in being able to return so many frogs to the wild”, says Danny Boiano, Aquatic Ecologist, at Sequoia and Kings Canyon National Parks.

One of the Sierra Nevada yellow-legged frogs is examined by a keeper at Oakland Zoo prior to release to the wild

Photo Credit: Oakland Zoo

The Zoo continue to care for 230 adult frogs at their biodiversity center. These will be released later this summer. A further 100 frogs will be released at the beginning of August.

Oakland Zoo will continue their efforts to save yellow-legged frogs in partnership with San Francisco Zoo & Gardens, the California Department of Fish and Wildlife, and National Park Service as long as they remain threatened.

Learn more about the related Southern Mountain Yellow-Legged Frog with our fact file – Southern Mountain Yellow-Legged Frog Fact File | The Animal Facts

Learn more about the Oakland Zoo on their website – Oakland Zoo