Hundreds of frogs once thought to be extinct released in Santa Monica Mountains

Nearly 600 California red-legged frog tadpoles that were raised at the Aquarium of the Pacific in Long Beach were released into streams in the Santa Monica Mountains, marking a hopeful step in restoring a threatened species once believed extinct in the area.

The tadpoles were rescued in March after late-winter storms damaged the frogs’ fragile breeding sites, aquarium officials said.

Biologists from the National Park Service salvaged the egg masses and brought them to the aquarium, where staff hatched and raised them over several months.

The emergency intervention is the latest in a decadelong effort to reestablish the federally threatened species in its former range. The California red-legged frog is also designated as a Species of Special Concern by the state.

“This project has had its share of ups and downs over the years,” said Katy Delaney, an ecologist with Santa Monica Mountains National Recreation Area. “But with committed partners like the aquarium, we’re writing another hopeful chapter in the comeback story of the California red-legged frog.”

Since reintroduction efforts began in 2014, biologists have worked to create self-sustaining populations in the mountains, where the species had not been seen since the 1970s. This year’s release is one of the largest yet and offers a boost after wildfires and severe weather disrupted earlier breeding efforts.

“We are so proud to be able to support the National Park Service in their work to help local populations of California red-legged frogs,” said Erin Lundy, conservation manager at the aquarium. “It’s incredibly meaningful to be able to play a role in the important work that they do.”

NPS biologists plan to monitor the release sites over the summer to track the tadpoles’ development into juvenile frogs and evaluate the success of the emergency response.

Earlier this month, the Los Angeles Zoo, in partnership with the Aquarium of the Pacific, released hundreds of endangered yellow-legged frogs in the San Gabriel Mountain range.