Snake River Cutthroat Trout

Oncorhynchus clarki

by Ken Schultz

TROUT, CUTTHROAT Oncorhynchus clarki. Other names: cut, native trout, coastal cutthroat, Clark's trout, red-throated trout, short-tailed trout, lake trout, sea trout, brook trout, native trout, Yellowstone cutthroat, Snake River cutthroat, Lahontan cutthroat, Rio Grande cutthroat, Colorado cutthroat, Utah cutthroat, Paiute cutthroat, harvest trout, blackspotted trout; French: truite fardée.

The term "cutthroat throat" and its scientific designation O. clarki -- the species name in honor of Capt. Clark of the Lewis and Clark expedition -- is more like a name for a family tree than for a single species of fish. According to some scientific estimates there are fourteen subspecies, hybrids, and variations, forming what has been called an ichthyological jigsaw puzzle of fish that are endemic to western North America. All of these are members of the Salmonidae family of salmons, trouts, whitefishes, and graylings, and were reclassified from the trout genus Salmo to the Pacific salmon genus Oncorhynchus.

Of the fourteen species, all but one inhabit only freshwater rivers, lakes, and streams; the exception is the coastal cutthroat trout, O. clarki clarki, which has both freshwater and anadromous forms; for reasons unknown, some fish migrate to sea while others stay in freshwater. The coastal cutthroat is fairly well distributed and available to anglers, and is one of the more prominent cutthroat species, in addition to the West Slope (intermountain) cutthroat, O. clarki lewisi; the Yellowstone cutthroat, O. clarki bouvieri; and the Lahontan cutthroat, O. clarki henshawi. Others species include the Bonneville cutthroat, blackspotted cutthroat, greenback cutthroat, and Rio Grande cutthroat.

Cutthroats are very popular with anglers, and generally not as selective as other trout species. They are not as acrobatic as rainbow trout, but strong fighters, and they have excellent eating flesh, which can range from white to red. They hybridize freely in nature with rainbow trout (which is called a cutbow), golden trout, and other close relatives.

Perhaps as much or more than other trout species, all cutthroat species and populations are sensitive to overhar-vest, pollution, stream warming, and habitat alteration. Some strains have been greatly diminished and others extirpated.

Identification. This is a highly variable fish, in coloration and size. The characteristic that gives the inland cutthroat its name is the yellow, orange, or red streak or slash mark in the skin fold on each side under the lower jaw. The color of the body ranges from cadmium blue and silvery (sea-run) to olive-green or yellowish green. There may or may not be red on the sides of the head, front part of the body, and the belly. In some specimens there may be a narrow pink streak along the sides, but not as broad as in the rainbow trout. The body is covered with black spots, which extend onto the dorsal, adipose, and tail fins. Some are literally covered with spots, while in others the spots are sparse and larger, being more numerous on the posterior part of the body. On the tail, the spots radiate evenly outward as they do in such species as the rainbow trout, golden trout, and Apache trout. While all of these species are very similar and closely related, only the cutthroat trout has hyoid teeth (teeth located on the back of the tongue). These may be difficult to see or obsolete in some specimens. The tail of the cutthroat is slightly forked and all the fins are soft-rayed.

Coastal cutthroat coloration also varies with habitat and life history. Resident fish living in bog ponds are typically from 6 to 16 inches long; are golden yellow with dark spots on the body, dorsal, and caudal fin; and have a vivid red slash mark under the jaw. Free-swimming residents in large landlocked lakes can exceed 24 inches long and are uniformly silver with black spots, having rosy gill covers and a faint slash mark. Sea-run cutthroats are smaller, seldom more than 18 inches long. They are bluish--silver with dark or olive backs and less conspicuous black spots; the characteristic slash is a faint yellow. Lack of a distinct slash mark in sea-run and resident forms has led anglers to confuse the fish with rainbow trout, but a sure identification of the cutthroat is it’s hyoid teeth.

Size/Age. The largest form (or subspecies) of O. clarki was once the Lahontan cutthroat, which was native to the Lahontan drainage system of Nevada and California, including Lake Tahoe, Pyramid Lake, and the Truckee River. These specimens had an average weight of about 20 pounds; a 41-pound Lahontan cutthroat caught in Pyramid Lake in 1925 is the all tackle world record for cutthroats. In 1938 water was diverted from the Truckee River and the Lahontan became extinct except for populations maintained by stocking, none of which attain the large sizes they once did, yet a number of fish from there have become line class world records in the 1980s and 1990s.

The smallest cutthroat occurs only in upper Silver King Creek, California, and does not exceed 12 inches. Coastal anadromous cutthroats have been recorded to 17 pounds but average under 5 pounds, while most inland specimens seldom exceed 5 pounds. Most cutthroats live 4 to 7 years, and they can have a maximum lifespan of at least 12 years.

Distribution. Cutthroat trout are the most widely distributed of all the western trouts of North America, which is proven by the many names that refer to rivers, states, or drainages where unique forms occur. The coastal cutthroat trout normally does not exist more than 100 miles inland. They are known from the Eel River, California, north to Prince William Sound, Alaska. Inland non-anadromous forms occur from southern Alberta, Canada, to as far south as New Mexico, as far east as Colorado and most of Montana, and west as far as Alberta and eastern California. A small, disjunct population which may have been transplanted occurs in northern Baja California, Mexico. The species has been transplanted to other locations, including the east coast of Quebec, Canada, and Europe.

Habitat. Inland cutthroat and resident (non-anadromous) coastal cutthroat live in a wide variety of coldwater habitats, from small headwater tributaries, mountain streams, and bog ponds to large lakes and rivers. During their spawning migration, sea-run cutthroat are usually found in river or stream systems with accessible lakes; otherwise they stay in saltwater near shore and their natal tributaries. In some watersheds, both anadromous and resident coastal cutthroats are found together.

Life History/Behavior. Cutthroat trout are late winter or early spring spawners, although sea-run fish typically ascend rivers from late summer through fall of the year prior to spawning. They spawn in small, isolated headwater streams; for anadromous coastal cutthroat, selection of isolated spawning areas is thought to reduce interaction of young cutthroat with more aggressive juvenile steelhead and coho salmon. The female makes one or more nests; eggs hatch in 6 to 7 weeks and, by the time they become parr, are difficult to distinguish from rainbow trout. Later, the young occupy beaver ponds, sloughs, or lakes. In lakes, smaller inland and non-anadromous coastal cutthroat trout hide among lily pads, sunken logs, or rubble from which they dart out and seize insects and small fish. Some fish abandon this "sit and wait" feeding strategy when they reach about 14 inches and become cruisers, pursuing and eating other fish. Cutthroat that adapt this feeding strategy can grow from 24 to 28 inches, weigh 8 pounds, and live to be over 12 years old. These trophy-class cut-throat are always found in large landlocked lakes with populations of kokanee salmon.

Sea-run juveniles can be displaced to down-stream mainstem and estuarine areas where they reside for the summer, then migrate back upstream with the onset of winter floods. Sea-run cutthroat rear for 3 to 4 years in freshwater and migrate to sea in spring when they are about 8 inches long. Time at sea varies from a few days to over a hundred days before they return to their natal stream. During their migration, they follow the shoreline and do not cross open bodies of water, seldom venturing farther than 30 to 45 miles from their home stream. In the fall they return to their home stream where they mature during the winter months. Homing is very precise; cutthroat can return to the same tributary stream where they emerged and reared. Fish mature at 5 to 7 years. Survival through the winter and return to saltwater is about 40 percent. A-bout 60 percent of the migrants are sexually mature, a characteristic that tends to limit egg deposition and reproductive potential.

Food. Inland cutthroats mostly consume insects and small fish. Coastal cutthroats eat various small fish, shrimp, sand worms, and squid.