New releases a leap forward for endangered frog in southern California

More than 650 southern mountain yellow-legged frogs, including nearly 400 raised at the Aquarium of the Pacific, were released into two San Gabriel Mountains sites this year as part of a two-decade multi-agency conservation effort. The species, once so common in Southern California that biologists say they had trouble avoiding stepping on them, has declined about 98% in its southern population, with fewer than 200 counted in a 2023 survey.

The frogs were bred at the Los Angeles Zoo, raised through metamorphosis at the aquarium, and driven two hours to release sites chosen for the fast water and deep pools the species prefers. The biggest ongoing threat isn't the introduced trout that started the decline decades ago but a chytrid fungus that has devastated amphibian populations worldwide and appears to hit this species especially hard.

Researchers at partner institutions are experimenting with anti-fungal treatments, immune priming, and identifying drier release sites where frogs might better fend off infection.

The full dispatch is available from the source below.