Mountain whitefish | |
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16 inches (41 cm) Mountain whitefish, McKenzie River, Oregon | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Salmoniformes |
Family: | Salmonidae |
Genus: | Prosopium |
Species: | P. williamsoni |
Binomial name | |
Prosopium williamsoni (Girard, 1856) | |
Synonyms [2] | |
Coregonus williamsoniGirard, 1856Coregonus oregoniusJordan & Snyder, 1909Prosopium oregonium(Jordan & Snyder, 1909) Contents |
The mountain whitefish (Prosopium williamsoni) is one of the most widely distributed salmonid fish of western North America. [3] It is found from the Mackenzie River drainage in Northwest Territories, Canada through western Canada and the northwestern USA in the Pacific, Hudson Bay and upper Missouri River basins to the Truckee River drainage in Nevada and Sevier River drainage in Utah. [4]
The body shape is superficially similar to the cyprinids, although it is distinguished by having both the adipose fin and axillary process of salmonids. The body is slender and nearly cylindrical in cross section, generally silver with a dusky olive-green shade dorsally. The scales possess pigmented borders, which are especially defined on the posterior end. Mountain whitefish possess a forked homocercal tail. The short head has a small mouth underneath the snout. The short dorsal fin has 12–13 rays, with 11–13 for the anal fin, 10–12 for the pelvic fins, and 14–18 for the pectoral fins. Size has been recorded at up to 70 centimeters (28 inches) in length and a weight of 2.9 kilograms (6.4 lb).
The spawning season is from October to early December, when water temperatures are 2–6 °C. Mountain whitefish congregate in large schools on fall spawning runs and seek out areas of coarse gravels or cobbles at depths of at least 75 cm (30 inches), typically in shallow areas of small tributaries or shorelines of lakes. Their non-adhesive eggs are scattered along the substrate. The eggs then develop slowly through the winter (6–10 weeks), hatching in the early spring, generally in March. [5] Mountain whitefish reach reproductive maturity at approximately three years old, females can produce as many as 4,000 eggs annually. [6] Mountain whitefish typically live between 7–9 years in the wild.
Mountain whitefish are demersal feeders, [7] stirring up the substrate with pectoral and tail fins to expose insect larvae and other invertebrates, including snails, crayfish, and amphipods. Their main feeding time is in the evening, but they will also take drifting prey during the day. The mountain whitefish frequently feeds in the lower strata of streams, but populations may rise to the surface to prey on hatching insects, including mayflies. Mountain whitefish fry are a common food source for other trout species. [8]
The mountain whitefish are commonly found in mountain streams and lakes, favoring clear cold water and large deep pools of at least a meter's depth; the Lake Tahoe population lives just above the bottom in deeper water. [9]
This species occurs throughout the western half of North America, as far north as the Mackenzie River (Canada) and the drainages of the Hudson Bay, in the Columbia River, upper Missouri River, upper Colorado River. [10]
Mountain whitefish are non-anadromous fish and spend the majority of their lives in freshwater ecosystems. Relatively little is known about the migration patterns of whitefish, but it is believed that they do migrate for spawning and because of temperature fluctuations. In the Methow River, a tributary of the Columbia River, mountain whitefish have been found migrating due to increases in shallower tributary water temperatures into the larger Columbia River. Mountain whitefish have also been known to spend the winter in the Columbia River which provides more suitable habitats for these fishes. Evidence shows that mountain whitefish in the Methow River are returning annually to the same headwater tributaries, which indicates migration for the primary purpose of returning to birth streams to spawn – similar to other anadromous salmonid species. [11]
To better understand the conservation and management needs of mountain whitefish biologists seek to understand life history strategies of these fishes. Understanding the growth, age structure, and age at maturity of these fish can better inform limitations on which fish can be harvested and which should be released. If the age at which the fish matures is known, management agencies can estimate sizes of these fishes and inform anglers that no fish under this maturation size may be kept to ensure new generations. The age of these fish can be determined by counting annuli (growth rings) in fish scales, pectoral fin rays, and otoliths (ear bones). Efficacy of these counting strategies can vary, but in combination they could provide vital data to ensure that Mountain Whitefish populations continue to stay at healthy levels. Some of the most effective ways to age mountain whitefish have been determined to be by examining scales for younger fishes or otoliths for older fishes. [12]
Mountain whitefish have a secure conservation status. [10] In many of the larger intermountain Western rivers, mountain whitefish are the only native salmonid. Mountain whitefish typically occur in high abundance, in the Snake River Basin in Idaho, mountain whitefish abundance was found to be 1,257/100 m. [13] Historically, mountain whitefish are not popular game fish and have been thrown onto the banks when caught because they are 'trash fish.' Similar to other native salmonids, mountain whitefish have received backlash because anglers believe that they are competing for food and spawning resources for more popular introduced species, like brook trout (Idaho). Due to common misconceptions, some native mountain whitefish populations have been decimated by both management agencies and anglers alike. The health of mountain whitefish, like other salmonids, can be a predictor of the health of the environment that they live in, so understanding and maintaining their populations can be beneficial for ecosystem prosperity. [12]
Trout is a generic common name for numerous species of carnivorous freshwater ray-finned fishes belonging to the genera Oncorhynchus, Salmo and Salvelinus, all of which are members of the subfamily Salmoninae in the family Salmonidae. The word trout is also used for some similar-shaped but non-salmonid fish, such as the spotted seatrout/speckled trout.
Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes, consisting of 11 extant genera and over 200 species collectively known as "salmonids" or "salmonoids". The family includes salmon, trout, char, graylings, freshwater whitefishes, taimens and lenoks, all coldwater mid-level predatory fish that inhabit the subarctic and cool temperate waters of the Northern Hemisphere. The Atlantic salmon, whose Latin name became that of its genus Salmo, is also the eponym of the family and order names.
The Little Spokane River is a major tributary of the Spokane River, approximately 35 miles (56 km) long, in eastern Washington in the United States. It drains a rural area of forested foothills and a farming valley north of the city of Spokane along the Idaho–Washington border. It has two branches, one starting west of Newport and the other stemming from Eloika Lake farther west.
The rainbow trout is a species of trout native to cold-water tributaries of the Pacific Ocean in North America and Asia. The steelhead is an anadromous (sea-run) form of the coastal rainbow trout(O. m. irideus) or Columbia River redband trout (O. m. gairdneri) that usually returns to freshwater to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead.
The Arctic grayling is a species of freshwater fish in the salmon family Salmonidae. T. arcticus is widespread throughout the Arctic and Pacific drainages in Canada, Alaska, and Siberia, as well as the upper Missouri River drainage in Montana. In the U.S. state of Arizona, an introduced population is found in the Lee Valley and other lakes in the White Mountains. They were also stocked at Toppings Lake by the Teton Range and in lakes in the high Uinta Mountains in Utah, as well as alpine lakes of the Boulder Mountains (Idaho) in central Idaho.
Sea trout is the common name usually applied to anadromous (sea-run) forms of brown trout, and is often referred to as Salmo trutta morpha trutta. Other names for anadromous brown trout are bull trout, sewin (Wales), peel or peal, mort, finnock (Scotland), white trout (Ireland), Dollaghan and salmon trout (culinary).
The Bitterroot River is a northward flowing 84-mile (135 km) river running through the Bitterroot Valley, from the confluence of its West and East forks near Conner in southern Ravalli County to its confluence with the Clark Fork River near Missoula in Missoula County, in western Montana. The Clark Fork River is a tributary to the Columbia River and ultimately, the Pacific Ocean. The Bitterroot River is a Blue Ribbon trout fishery with a healthy population of native westslope cutthroat trout and bull trout. It is the third most fly fished river in Montana behind the Madison and Big Horn Rivers.
Oncorhynchus is a genus of ray-finned fish in the subfamily Salmoninae of the family Salmonidae, native to coldwater tributaries of the North Pacific basin. The genus contains twelve extant species, namely six species of Pacific salmon and six species of Pacific trout, all of which are migratory mid-level predatory fish that display natal homing and semelparity.
The round whitefish is a freshwater species of fish that is found in North American drainages from Alaska to New England, including the Great Lakes except for Lake Erie, and in Arctic tributaries of northeast Asia, as well as northern Kamchatka Peninsula and the northern coasts of the Sea of Okhotsk. It has an olive-brown back with light silvery sides and underside and its length is generally between 9 and 19 inches. They are bottom feeders, feeding mostly on invertebrates, such as crustaceans, insect larvae, and fish eggs. Some other fish species, like white sucker in turn eat their eggs. Lake trout, northern pike and burbot are natural predators. Other common names of the round whitefish are Menominee, pilot fish, frost fish, round-fish, and Menominee whitefish. The common name "round whitefish" is also sometimes used to describe Coregonus huntsmani, a salmonid more commonly known as the Atlantic whitefish.
Redband trout are a group of three recognized subspecies of rainbow trout. They occur in three distinct regions in Pacific basin tributaries and endorheic basins in the western United States. The three subspecies are the Columbia River redband trout, the McCloud River redband trout and the Great Basin redband trout.
The Bonneville whitefish is a salmonid fish endemic to Bear Lake on the Utah-Idaho border. It is one of three species of Prosopium endemic to Bear Lake, the other two being the Bear Lake whitefish and the Bonneville cisco. The species is listed as a Wildlife Species of Concern by the Utah Division of Wildlife Resources.
The westslope cutthroat trout, also known as the black-spotted trout, common cutthroat trout and red-throated trout is a subspecies of the cutthroat trout and is a freshwater fish in the salmon family of order Salmoniformes. The cutthroat is the Montana state fish. This subspecies is a species of concern in its Montana and British Columbia ranges and is considered threatened in its native range in Alberta.
The coastal cutthroat trout, also known as the sea-run cutthroat trout, blue-back trout or harvest trout, is one of the several subspecies of cutthroat trout found in Western North America. The coastal cutthroat trout occurs in four distinct forms. A semi-anadromous or sea-run form is the most well known. Freshwater forms occur in both large and small rivers and streams and lake environments. The native range of the coastal cutthroat trout extends south from the southern coastline of the Kenai Peninsula in Alaska to the Eel River in Northern California. Coastal cutthroat trout are resident in tributary streams and rivers of the Pacific basin and are rarely found more than 100 miles (160 km) from the ocean.
The pygmy whitefish is a freshwater whitefish of the genus Prosopium in the family Salmonidae. Found in the mountain streams and lakes in western North America, it also has isolated populations in Lake Superior and in Ekityki Lake, Chukchi Peninsula.
The Whitefish River is a 24.8-mile-long (39.9 km) southward-flowing stream originating at the outlet of Whitefish Lake. The river is a tributary of the Stillwater River just before it reaches the Flathead River in Flathead County, in the U.S. state of Montana. The Whitefish River is part of the Columbia River basin, as the Flathead River is a tributary of Clark Fork, which is a tributary to the Pend Oreille River, which is a tributary to the Columbia River.
The kokanee salmon, also known as the kokanee trout, little redfish, silver trout, kikanning, Kennerly's salmon, Kennerly's trout, or Walla, is the non-anadromous form of the sockeye salmon. There is some debate as to whether the kokanee and its sea-going relative are separate species; geographic isolation, failure to interbreed, and genetic distinction point toward a recent divergence in the history of the two groups. The divergence most likely occurred around 15,000 years ago when a large ice melt created a series of freshwater lakes and rivers across the northern part of North America. While some members of the salmon and trout family (salmonids) went out to sea (anadromous), others stayed behind in fresh water (non-anadromous). The separation of the sockeye and the kokanee created a unique example of sympatric speciation that is relatively new in evolutionary terms. While they occupy the same areas and habitats during the breeding season, when ocean-going sockeye salmon return to freshwater to spawn, the two populations do not mate with each other in some regions, suggesting speciation.
Whitefish Lake ; is a natural oligotrophic freshwater lake in Flathead County, Montana, United States.