LOS ANGELES — The Los Angeles Zoo has released 450 tadpoles and 193 subadult southern mountain yellow-legged frogs into the streams of the San Gabriel Mountains in an effort to restore the species where they were once abundant, it was announced on Thursday, July 10.

With the exception of about 38 frogs, zoo representatives alongside other conservationists released the amphibians that were bred and raised as part of a long-running conservation program into remote parts of the mountains. Since the program began in 2007, the zoo has bred the endangered species and released more than 6,000 of them into their natural range.

Byron Wusstig, curator of ectotherms at the L.A. Zoo, described the release as a major step in recovering a local endangered species.

“I look forward to seeing these tadpoles and frogs help repopulate these remote areas of the San Gabriel Mountains and to continue innovative breeding and husbandry practices that support this long-running recovery effort with the USGS and partners,” Wusstig said in a statement.

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Luc Myers, an animal keeper, joined the recent expedition to release the frogs — his second time taking the journey.

“Hiking out on the San Gabriels with a cooler on my back, carrying these precious frogs was nothing short of amazing,” Myers said in a statement. “I’m thrilled I could play a part in this larger recovery effort and work with the USGS and our partners in the recovery program to help this endangered frog that calls Southern California home.”

Frogs bred at the zoo are hatched and raised to ensure their development. The zoo designed an amphibian breeding room to create an ideal environment for these creatures.

After reaching maturity, these frogs and tadpoles return home.

According to zoo officials, this year they expanded their program. Staff members are currently creating a so-called “headstarting facility” at an unused space in the Children’s Discovery Center, which is being renovated with specialized tanks and equipment to house frogs as they mature.

In the future, tadpoles will be able to grow bigger before their release. This is likely to increase their chances at survival, the zoo said.

The International Union for Conservation of Nature has classified the southern mountain yellow-legged frog as endangered. This species lives in perennial streams in select areas of the San Gabriel, San Bernardino and San Jacinto Mountains.

They are medium-sized amphibians at about 1.5 to 3.25 inches on average. Adult frogs are a mix of brown and yellow coloring, but some are gray, red or greenish-brown with dark spots or splotches, also called cryptic coloration.

Visitors can catch a glimpse of these frogs at the zoo’s Living Amphibian, Invertebrate and Reptile exhibit.