Friday October 27, 2023
CalTrout —
Lahontan cutthroat trout (LCT) were once widespread across high-elevation mountain streams and lakes in California and Nevada including Lake Tahoe. Today, they are much harder to find. Approximately 95% of the species has been extirpated from their historic habitat in California largely due to introduction of non-native trout species and habitat alterations by human land use activity. In the Walker Basin, part of the LCT’s native range, CalTrout is partnering on restoration projects to eliminate non-native trout populations from the system and help maintain these LCT populations.
Silver Creek is a tributary to the West Walker River, and LCT populations can be an indicator for drought resistance in the greater Walker Basin. When these fish are struggling, it likely means that rivers and streams are also in bad shape.
In Silver Creek, CalTrout works with the California Department of Fish and Wildlife (CDFW) to remove non-native brook trout. Before beginning removal efforts, staff took eDNA samples of the creek. These samples provide information about where certain species are present or absent from a watershed. From the samples taken we found that towards the headwaters of the creek there was an absence of invasive brook trout while lower in the stream they were present. Knowing where non-native species are in the watershed helps us focus our removal efforts.