The Lahontan cutthroat trout (Oncorhynchus clarkii henshawi) is a striking subspecies of cutthroat trout native to the high-desert waters of the Lahontan Basin in northern Nevada, eastern California, and southern Oregon. Renowned for their orange to reddish slash-like markings beneath the jaw, they vary widely in color—ranging from a silvery hue in lake-dwelling populations to more vivid patterns in riverine environments. Once capable of reaching remarkable sizes—particularly in the now-altered Pyramid Lake ecosystem—these trout have suffered declines due to habitat loss, overfishing, and competition with introduced species, and livestock grazing.
Livestock Grazing
Cattle grazing along streams has significant impacts on trout populations. As cattle trample stream banks, they erode soil, widen the streams, and introduce sediment that clouds the water. This sediment settles over gravel beds critical for trout spawning, obstructing oxygen flow to eggs and young fish. Grazing also reduces streamside vegetation, which normally provides essential shade to keep water temperatures cool—a necessity for trout, which are highly sensitive to heat. Without this vegetation, water temperatures can rise to levels that stress or even kill trout. Cattle excrement adds excess nutrients, promoting algae blooms and depleting oxygen, which further degrades the habitat. Together, these changes disrupt the trout’s lifecycle, leading to declining populations and even local extinction in heavily affected streams.
A recent five-year status review by the U.S. Fish and Wildlife Service found Lahontan cutthroat trout populations in deep trouble, with only 5 out of 71 populations categorized as resilient.
Only 7% of the stream-length in the trout’s habitat fall within grazing allotments that meet Bureau of Land Management land health standards across their range. More than 400 km of occupied streams pass through allotments failing to meet standards due to current livestock grazing. In Nevada, 63 percent of grazing allotments that contain LCT habitat are failing land health standards.
Proposed Change in Management
The Bureau of Land Management state office in Nevada is currently evaluating livestock management across 38 grazing allotments that contain critical trout habitat. The Bureau is proposing to “increase operational flexibility” for ranchers. Unfortunately, most of the proposed remedies would rely on additional infrastructure like water developments and fencing on public lands rather than simply reducing livestock levels or removing grazing from LCT streams.
