Lahontan Cutthroat Trout

Sagehen was originally founded for fisheries and wildlife research. A big part of what we know about wild Brook trout today comes out of work by Sagehen Director Paul “Doc” Needham and his graduate students in the 1950’s. Today, Sagehen remains the California benchmark stream for wild trout biomass.

Needham was the first to recognize that the Lahontan Cutthroat Trout (LCT) of adjacent Independence Lake was the last self-reproducing native and genetically pure population of this species, the largest trout in the world. This population was historically connected to Sagehen Creek. Needham’s student, Robert Lea wrote the definitive graduate thesis on these fish. A more recent Sagehen Master’s thesis evaluated competition between native and non-native trout, confirming the inability of LCTs to compete with introduced wild Brook, Brown and Rainbow trout.

As our surface and groundwater continues to warm in the region, these highly sensitive non-native trout will begin to find our streams uninhabitable. Anecdotally, this appears to already be happening at Sagehen, with no Rainbow or Brown trout in evidence for the past few sampling years. The native Lahontan Cutthroat Trout, however, evolved in the receding waters of endorheic (closed basin) Pleistocene Lake Lahontan, equipping the animal to deal with a much broader range of temperature, flow, salinity, turbidity and pH.

If we are to have trout in the food web of northern Sierra streams in the not-too-distant future (and we should), it seems that the most likely survivor will be the original one: the Lahontan Cutthroat Trout. The US Fish & Wildlife Service is working to establish protected headwaters populations that can eventually backfeed the entire system.

Major partners: US Fish & Wildlife Service, California Department of Fish and Wildlife, US Forest Service, Trout Unlimited, CalTrout, Truckee River Watershed Council.