Cutthroat Trout (Oncorhynchus clarki)

Cutthroat Trout (Oncorhynchus clarki)

The term “cutthroat throat” and its scientific designation O. clarki—the species name in honor of Captain 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 14 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 salmon, trout, whitefish, and grayling, and were reclassified from the trout genus Salmo to the Pacific salmon genus Oncorhynchus.

Of the 14 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 unknown reasons, some fish migrate to sea, whereas 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). Other species include the Bonneville cutthroat, the blackspotted cutthroat, the greenback cutthroat, and the Rio Grande cutthroat.

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 be red on the sides of the head, the 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, the adipose, and the tail fins. On the tail, which is slightly forked, the spots radiate evenly outward.

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 and the dorsal and the caudal fin, and have a vivid red slash mark under the jaw.

Free-swimming residents in large landlocked lakes can exceed 24 inches, are uniformly silver with black spots, and have rosy gill covers and a faint slash mark. Sea-run cutthroat are seldom more than 18 inches long; they have bluish silver with dark or olive backs and less conspicuous black spots; the characteristic slash is a faint yellow.

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

Life history/Behavior

Cutthroat trout are late-winter or early-spring spawners, although sea-run fish typically ascend rivers from late summer through the fall of the year prior to spawning. They spawn in small, isolated headwater streams. The female makes one or more nests; eggs hatch in 6 to 7 weeks. Later, the young occupy beaver ponds, sloughs, or lakes.

In lakes, smaller inland and nonanadromous 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 and weigh 8 pounds.

Food

Inland cutthroat mostly consume insects and small fish. Coastal cutthroat eat various small fish, shrimp, sandworms, and squid.

Other Names

cut, native trout, coastal cutthroat, Clark’s trout, red-throated trout, shorttailed 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.

Distribution

Cutthroat trout are the most widely distributed of all the western trout 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. It is known from the Eel River, California, north to Prince William Sound, Alaska.

Inland nonanadromous 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 faras Alberta and eastern California. A small, disjunct population that 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 (nonanadromous) 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 cutthroat occur together.
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