LONG BEACH, Calif. — The Aquarium of the Pacific said in a Sept. 10 release that approximately 653 critically endangered southern mountain yellow-legged frogs had been returned to California mountain habitat. Of that group, 394 frogs had been raised at the Long Beach aquarium. The institution said the release brought its contribution to 1,032 frogs raised and released since it joined the recovery effort in 2021. The numbers describe the aquarium’s contribution, not a count of the species’ wild population.
The Aquarium’s Sept. 10 event release announced the cohort and named the Los Angeles Zoo and U.S. Geological Survey as release partners. An Oct. 17 USA Today Network report by Denis Akbari described how the young frogs were prepared and transported. The field release took place Aug. 19, 2026, according to the Aquarium’s photo caption. Its announcement followed Sept. 10; the USA Today Network report appeared Oct. 17.
According to the Aquarium’s release, the work begins at the Los Angeles Zoo, where the frogs are bred. Tadpoles are transferred to the Aquarium of the Pacific, whose staff raise them through metamorphosis until they become froglets or frogs ready for the wild. Aquarium staff told USA Today Network that the process typically takes one to two years. The aquarium’s nursery role gives the small animals time to grow before they leave the controlled environment and return to their native range.
Preparation includes individual health checks. Staff assess each frog’s mobility, body condition and general health before deciding it is ready for release. The reporting said the animals are fed more heavily in the weeks beforehand. Those steps are part of the care needed for a group that has spent months or longer in human care; the sources do not suggest that the release alone ensures survival.
The USA Today Network report says release day begins before sunrise, with staff arriving around 4:45 a.m. to collect and package the frogs. After driving and hiking into the mountain habitat, the group acclimated the frogs to the water before letting them go at several locations. Spreading the animals across multiple places was intended to distribute the population rather than put every frog in one spot.
The partnership includes more than the two institutions that breed and raise the animals. The Aquarium’s release named the U.S. Geological Survey, U.S. Fish and Wildlife Service, U.S. Forest Service and California Department of Fish and Wildlife as partners that help monitor or oversee release work. USA Today Network reported that the Los Angeles Zoo produces the tadpoles, while aquarium staff take on the raising stage. The different roles connect breeding, care and field monitoring across organizations.
A Sept. 21 Long Beach Post report, distributed through an Associated Press partnership, described another layer of planning: staff separate frogs by genetic line and population of origin so animals can return to the appropriate native range. It also reported that some tadpoles move to the Santa Ana Zoo to keep growing before later reintroduction. That planning means a release involves decisions about the animals’ origins as well as their readiness for the field.
Southern mountain yellow-legged frogs are native to the San Gabriel, San Bernardino and San Jacinto mountains, according to the Aquarium and the reporting. The Aquarium joined the effort after the 2020 Bobcat Fire, which burned habitat used by the species. The recovery program responds to a long decline, but the latest release is one step in that work, not a measure that the species has recovered.
Biologists assess the results over time by looking for surviving frogs and evidence of breeding. Aquarium conservation manager Erin Lundy told USA Today Network that frogs have been found at sites where they had not been observed before releases. The article attributes that observation to Lundy; it does not present a new census or estimate of the wider wild population. Continued monitoring will help researchers learn how the animals fare after reintroduction.
The Aquarium said it is preparing equipment and habitats for another season of raising frogs through winter and spring, with a future release planned for next summer. The cycle shows why the total is a cumulative figure: a release day depends on earlier breeding and care, and its outcome can only be judged as monitoring continues. For now, the reported cohort of approximately 653 frogs marks a substantial addition to the partners’ work, including the 394 animals raised at the Aquarium of the Pacific.
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