Science Spotlight

  • July 6, 2020

Isaac Chellman, high mountain lakes environmental scientist for CDFW’s North Central Region, nets non-native trout from a lake to restore native frog habitat.

Sierra Nevada yellow-legged frog sits among the reeds in its high mountain lake environments with trees and blue sky in the background
The Sierra Nevada yellow-legged frog is listed as a threatened species under both the California and federal endangered species acts.

close up look of a Sierra Nevada yellow legged frog, which blends in well into its native, high mountain lake habitat. The frog is on a dark rock partially in a lake
Non-native trout introduced into high mountain lakes prey upon native Sierra Nevada yellow-legged frog tadpoles and young frogs. Removing these trout from select lakes is an important step in recovering native frog populations.

In the Tahoe National Forest, California Department of Fish and Wildlife scientists are working to balance native species restoration with recreational fishing.

This summer, for the first time in the Tahoe National Forest, CDFW will begin work to restore Sierra Nevada yellow-legged frog (Rana sierrae) habitat by removing introduced trout from four alpine lakes and four small ponds within the Five Lakes Basin area. The Sierra Nevada yellow-legged frog is listed as threatened under California’s Endangered Species Act and endangered under the federal Endangered Species Act. 

The Five Lakes Basin is located in Nevada County, south of French Lake and Faucherie Lake within the Grouse Ridge non-motorized area of the Tahoe National Forest. The area is a popular destination for backcountry recreation. The small lakes and ponds targeted for fish removal include Glacier Lake and are typically accessed from the Grouse Ridge Campground and Faucherie Lake.

“These types of projects highlight CDFW’s dual mission to both provide recreational opportunities and recover native species,” said Sarah Mussulman, Sierra fisheries supervisor for CDFW’s North Central Region. “In this case, we want to ensure anglers have a chance to catch a fish at a beautiful lake while simultaneously ensuring this iconic native frog remains on the landscape for generations to come. Because the fish are a major driver of frog declines, we’ve chosen one area near Grouse Ridge to recover frogs and a nearby area to plant fish.”

To remove the fish, which consist of non-native brook, rainbow and hybridized golden-rainbow trout, CDFW will use mechanical methods including monofilament gill nets and backpack electrofishing units. This project is funded by the U.S. Fish and Wildlife Service through its endangered species recovery grant program and will be conducted in collaboration with the Tahoe National Forest. Work is scheduled to begin by mid-summer and will continue through the fall 2022.

The Sierra Nevada yellow-legged frog was once one of the most abundant species in the Sierra and a critical part of the natural food chain. Non-native trout, which were introduced into historically fishless lakes and ponds throughout the range for many decades, consume young frogs and tadpoles. This predation has been a major contributor to the decline of these native amphibians. The restoration project will provide additional fishless habitat, which is needed for the long-term survival and eventual recovery of this species.

At the same time, CDFW is committed to promoting and maintaining the unique recreational fishing opportunities nearby. CDFW will continue to stock trout into many lakes in the Grouse Ridge area, including Carr, Culbertson, Feeley, Long, Milk, Upper and Lower Lindsey, Big and Little Island, and Lower and Upper Rock lakes. These locations provide fishing opportunities at beautiful, high elevation lakes within a few miles of the Five Lakes Basin.


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