More than 1,000 critically endangered southern mountain yellow-legged frogs raised at the Aquarium of the Pacific have been released into their native California mountain habitat, marking a milestone in the effort to recover the species.
The latest release saw approximately 653 southern mountain yellow-legged frogs released by staff from the Aquarium of the Pacific, Los Angeles Zoo and U.S. Geological Survey. Of those, 394 frogs were reared at the Aquarium, making it the institution’s largest release of the species to date and bringing its total contribution to 1,032 frogs released.
“This milestone is a reflection of the incredible support we’ve received from the public, our donors, visitors and partners,” said Erin Lundy, senior manager of conservation
initiatives at the Aquarium of the Pacific. “We’re incredibly proud of what we’ve accomplished together and grateful to everyone who has helped us get here.”
The southern mountain yellow-legged frog is native to the San Gabriel, San Bernardino and San Jacinto mountains. The species has experienced significant population declines over the decades, prompting a long-running recovery effort involving government agencies, zoos and conservation organizations.
The Aquarium joined those efforts following the 2020 Bobcat Fire, which burned much of the species’ remaining habitat. The Aquarium serves as a nursery, raising tadpoles bred at the Los Angeles Zoo through metamorphosis until they are ready for release, a process that typically takes one to two years.
“We work with a lot of partners, and a lot of coordinated effort between our partners made this work possible,” Lundy said.
Before release, Aquarium staff ensure the frogs have completed metamorphosis and are healthy enough for life in the wild. Animals are routinely assessed for mobility, body condition and overall health, and are fed more heavily in the weeks leading up to release.
Release day begins before sunrise. Staff arrive around 4:45 a.m. to collect and package the frogs before transporting them to the release site. After a drive and hike into the mountain habitat, the frogs are acclimated to the water before being released across multiple locations to help spread out the population.
“Seeing the little frogs jump out and swim off is awesome,” Lundy said. “We all came away from that day feeling so invigorated by the work that we do and energized to keep moving forward.”
This year’s release was the Aquarium’s largest since it began participating in southern mountain yellow-legged frog recovery efforts in 2021.
“I could not be more proud to have watched this project grow from our very first batch of tadpoles rescued from the Bobcat Fire to rearing our largest group of this species and successfully releasing almost 400 of them this year,” Lundy said.
Success is measured over time as biologists monitor release sites for surviving frogs and evidence of breeding. According to Lundy, frogs have been found at locations where they were previously absent before releases occurred, indicating the recovery effort is helping bolster wild populations.
The Aquarium is already preparing for the next group of tadpoles. Following this year’s release, staff are maintaining equipment and readying habitats before beginning another season of rearing frogs through the winter and spring for release next summer.
This article originally appeared on USA TODAY: Endangered frogs raised at Aquarium of the Pacific return to the wild













