Nevada State Fish

Lahontan Cutthroat Trout

(Oncorhynchus clarki henshawi)

Adopted in 1981.

The Lahontan Cutthroat Trout, Oncorhynchus clarki henshawi, was designated the official state fish in 1981.

It might seem surprising that a trout could survive in fourteen of arid Nevada's seventeen counties. As you might guess, it's a hardy fish, occupying habitats ranging from mountain streams and alpine lakes to seasonal lowland streams and alkaline lakes where no other trout can survive.

Yet the Lahontan cutthroat trout was once even more widespread. It's named for Lake Lahontan, which covered parts of western Nevada and northeastern California during the Pleistocene Epoch, or Ice Age. At the end of the Ice Age, Nevada's climate became more arid. Lake Lahontan and other large Great Basin lakes began drying up, leaving smaller lakes, some of which are too salty for freshwater fishes (like Utah's Great Salt Lake).

Today, the Lahontan cutthroat is the only trout native to west-central Nevada's Lahontan Basin, a part of the much larger Great Basin. The fish was much more abundant before Nevada was settled. It was a primary food source for several Great Basin Indian tribes. Loss of habitat, overfishing, and introduced fishes have greatly depleted populations.

There was even a commercial fishery for Lahontan cutthroats in Lake Tahoe and Pyramid Lake at the beginning of this century, though it petered out after a few decades. The largest known specimens, weighing more than forty pounds, came from Pyramid Lake, though this stock is now extinct.

Description and Life History

Although coloration is variable, this species is generally heavily marked with large, rounded black spots, more or less evenly distributed over the sides, head, and abdomen. Spawning fish generally develop bright red coloration on the underside of the mandible and on the opercle. In spawning males, coloration is generally more intense than in females.

Lahontan cutthroat trout are obligate but opportunistic stream spawners. Typically, they spawn from April through July, depending on water temperature and flow characteristics. Autumn spawning runs have been reported from some populations. The fish may reproduce more than once, though post-spawning mortality is high (60-90%). Lake residents migrate into streams to spawn, typically in riffles on well washed gravels. The behavior of this subspecies is typical of stream spawning trout; adults court, pair, and deposit and fertilize eggs in a redd dug by the female.

 
Although the Lahontan cutthroat in Oregon were originally classified as Willow-Whitehorse cutthroat trout, genetic and taxonomic investigations led to its re-classification in 1991 (Williams 1991).

Habitat

The Lahontan cutthroat trout is one subspecies of the wide-ranging cutthroat trout species (O. clarki) that includes at least 14 recognized forms in the western United States. Cutthroat trout have the most extensive range of any inland trout species of western North America, and occur in anadromous, non-anadromous, fluvial, and lacustrine populations (Behnke 1979). Many of the basins in which cutthroat trout occur contain remnants of much more extensive bodies of water which were present during the wetter period of the late Pleistocene epoch (Smith 1978).

These fish are unusually tolerant of both high temperatures (>27 C) and large daily fluctuations (up to 20 C). They are also quite tolerant of high alkalinity (>3000 mg/l) and dissolved solids (>10000 mg/l). They are apparently intolerant of competition or predation by non-native salmonids, and rarely coexist with them (Behnke 1992, LaRivers 1962).