Endangered frogs released into the wild

By Alex Feltes, Birch Aquarium at Scripps Institution of Oceanography, UC San Diego

This summer, 223 captive-raised mountain yellow-legged frogs were released into their native habitat at UC Nature’s James San Jacinto Mountains Reserve. The release marks the second successful reintroduction of this endangered amphibian this year by Birch Aquarium at Scripps Institution of Oceanography.

“It was incredibly exciting to be part of another successful release of Mountain Yellow-legged Frogs. After watching these frogs grow from tadpoles into healthy juveniles, there’s something especially rewarding about seeing them take that final leap back into their native habitat,” said Sean Bruce, Assistant Curator of Fishes and Invertebrates.

The aquarium received the frogs as tadpoles from the San Diego Zoo Wildlife Alliance (SDZWA) last summer and raised them behind the scenes until they were ready for release. To support a healthy, widespread population, the frogs were then released in two groups at different locations throughout the San Jacinto Mountains. Researchers from SDZWA and the U.S. Forest Service joined Birch Aquarium at both releases to help support the effort.

Frogs gone wild

The first release took place in early August, when approximately 74 frogs were released along a creek near Idyllwild, California. The site also offered encouraging signs of recovery, as researchers spotted several adult frogs that SDZWA had previously released as tadpoles. Researchers were even able to tag one of the frogs, allowing them to track its progress in the years ahead.

A few weeks later, Birch Aquarium completed its second release just a few miles down the road along another creek, releasing 149 frogs. Alongside the aquarium, SDZWA also released two additional frogs and 170 tadpoles as part of their ongoing reintroduction work.

“Spotting wild frogs at one of the release sites was especially meaningful, as it was an encouraging sign of a healthy habitat and gave me hope that our newly released frogs can thrive there, too,” said Bruce.

Going forward, researchers will continue to monitor the frogs at the release sites several times a year, tracking their progress and looking for further signs of recovery.

The James San Jacinto Mountains Reserve was the site of the first release of captive-bred mountain yellow-legged frog eggs and tadpoles into the wild in 2010.

A leap forward, together

To date, Birch Aquarium has reintroduced more than 440 Mountain Yellow-legged Frogs into the wild as part of an ongoing collaborative effort with partners across the region.

“The San Diego Zoo Wildlife Alliance has been an amazing partner, and I’m incredibly proud of the work we’ve done together to support this important conservation program for our region’s native wildlife,” said Bruce.

Alongside SDZWA, several other partners are involved in this long-running recovery program, including the U.S. Fish and Wildlife Service, U.S. Geological Survey and California Department of Fish and Wildlife. Together, these partners are working to enhance the genetic diversity of captive and wild populations, improve reintroduction efforts and increase wild frog populations.

This ongoing conservation work is also at the heart of Birch Aquarium’s Imagine Wild: Mountain Yellow-legged Frog exhibition, presented by The Lodge at Torrey Pines, which highlights the collaborative efforts underway to help bring this endangered species back to the wild.