Efforts to re-establish Lahontan cutthroat trout in Fallen Leaf Lake have resulted in a native, lacustrine strain of LCT to spawn in the Lake Tahoe Basin for the first time since their extirpation in the 1930.
The U.S. Fish and Wildlife Service with partners began stocking Fallen Leaf in 2002 with Pilot Peak Lahontan cutthroat trout. This effort was undertaken in order to reintroduce a lake form of this subspecies within the Tahoe basin. The Pilot Peak LCT strain is native to the basin.
This lake strain is thought to live 15 to 20 years.
The largest LCT captured prior to the 1930s from Fallen Leaf Lake was 29 pounds. The California state record for this subspecies is from Lake Tahoe in 1911 and weighed more than 31 pounds.
Fallen Leaf Lake is historic LCT habitat connected to Lake Tahoe by Taylor Creek.
To manage Lahontan spawning and prevent hybridization with rainbow trout, two weirs have been installed in Glen Alpine Creek, one at the interface of the lake and creek and the other approximately 230 meters upstream. Both weirs have been in place since mid-March to control access to spawning areas from Fallen Leaf Lake and act as a barricade to downstream movement of rainbow trout in the upper watershed. Although the weirs block access for mature trout to Glen Alpine Creek, other native species found in the watershed, Lahontan redside shiners, Paiute sculpin, and speckled dace are able to move through the half inch spacing of the bars at either weir.
Upon completion of the spawning season, both weirs will be outfitted with a fry box to capture fry produced within and above the spawning areas to ensure that hybridization is not occurring and to measure LCT reproductive success. Once fry are checked genetically, LCT will be released into Fallen Leaf Lake.