Trout

Rainbow trout, Oncorhynchus mykiss

Biwa trout (or Biwa salmon), Oncorhynchus masou rhodurus

Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout but, unlike most trout, most salmon species spend almost all their lives in salt water. Trout are classified as an oily fish.^[1]
The word trout is also used as part of the name of some non-salmonid fish such as Cynoscion nebulosus, the spotted seatrout or speckled trout.

Contents 1 Species 2 Anatomy 3 Habitat 4 Diet 5 As food 6 River fishing

Species

The name trout is commonly used for some species in three of the seven genera in the subfamily Salmoninae: Salmo, Atlantic species; Oncorhynchus, Pacific species; and Salvelinus, which includes fish also sometimes called char or charr. Fish referred to as trout include:

• Genus Salmo
  • Adriatic trout, Salmo obtusirostris
  • Brown trout, Salmo trutta
  • Flathead trout, Salmo platycephalus
  • Marble trout, Soca River trout or Soča trout - Salmo trutta marmoratus
  • Ohrid trout, Salmo letnica
  • Sevan trout, Salmo ischchan
  • Sea trout, Salmo trutta (The same as the Brown trout, Brown and Sea trout are almost genetically identical^{[citation needed]})

• Genus Oncorhynchus
  • Apache trout, Oncorhynchus apache
  • Biwa trout, Oncorhynchus masou rhodurus
  • Cutthroat trout, Oncorhynchus clarki
    The cutthroat trout has 15 recognized subspecies (depending on sources), such as the Lahontan cutthroat trout, Oncorhynchus clarki henshawi, Bonneville cutthroat trout, Oncorhynchus clarki utah, Colorado River cutthroat trout, Yellowstone cutthroat trout.
  • Gila trout, Oncorhynchus gilae
  • Golden trout, Oncorhynchus aguabonita
  • Rainbow trout, Oncorhynchus mykiss
  • Mexican Golden Trout, Oncorhynchus chrysogaster and as many as eight other species or sub-species in northwest Mexico, not yet formally named.

• Genus Salvelinus (Char)
  • Arctic char, Salvelinus alpinus
  • Aurora trout, Salvelinus fontinalis timagamiensis
  • Brook trout, Salvelinus fontinalis
  • Bull trout, Salvelinus confluentus
  • Dolly Varden trout, Salvelinus malma
  • Lake trout, Salvelinus namaycush
  • Silver trout, † Salvelinus fontinalis agassizi (extinct)

Anatomy

Trout that live in different environments can have dramatically different colorations and patterns. Mostly, these colors and patterns form as camouflage, based on the surroundings, and will change as the fish moves to different habitats. Trout in, or newly returned from the sea, can look very silvery, while the same "geneic" fish living in a small stream or in an alpine lake could have pronounced markings and more vivid coloration; it is also possible that in some species this signifies that they are ready to mate. It is virtually impossible to define a particular color pattern as belonging to a specific breed; however, in general, wild fish are claimed to have more vivid colors and patterns.
Trout have fins entirely without spines, and all of them have a small adipose fin along the back, near the tail. There are many species, and even more populations that are isolated from each other and morphologically different. However, since many of these distinct populations show no significant genetic differences, what may appear to be a large number of species is considered a much smaller number of distinct species by most ichthyologists. The trout found in the eastern United States are a good example of this. The brook trout, the aurora trout, and the (extinct) silver trout all have physical characteristics and colorations that distinguish them, yet genetic analysis shows that they are one species, Salvelinus fontinalis.
Lake trout (Salvelinus namaycush), like brook trout, belong to the char genus. Lake trout inhabit many of the larger lakes in North America, and live much longer than rainbow trout, which have an average maximum lifespan of 7 years. Lake trout can live many decades, and can grow to more than 30 kilograms (66 lb).

Habitat

A trout farm in Sochi, Russia

Trout are usually found in cool (50–60 °F, 10–16 °C), clear streams and lakes, although many of the species have anadromous strains as well. Young trout are referred to as troutlet, troutling or fry. They are distributed naturally throughout North America, northern Asia and Europe. Several species of trout were introduced to Australia and New Zealand by amateur fishing enthusiasts in the 19th century, effectively displacing and endangering several upland native fish species. The introduced species included brown trout from England and rainbow trout from California. The rainbow trout were a steelhead strain, generally accepted as coming from Sonoma Creek. The rainbow trout of New Zealand still show the steelhead tendency to run up rivers in winter to spawn.^[2] The closest resemblance of seema trout and other trout family can be found in the Himalayan Region of India, Nepal, Bhutan, Pakistan and in Tian Shan mountains of Kyrgyzstan.

Diet

Trout generally feed on other fish, and soft bodied aquatic invertebrates, such as flies, mayflies, caddisflies, stoneflies, mollusks and dragonflies. In lakes, various species of zooplankton often form a large part of the diet. In general, trout longer than about 300 millimetres (12 in) prey almost exclusively on fish, where they are available. Adult trout will devour smaller fish up to 1/3 their length. Trout may feed on shrimp, mealworms, bloodworms, insects, small animal parts, and eel.

As food

As a group, trout are somewhat bony, but the flesh is generally considered to be tasty. The flavor of the flesh is heavily influenced by the diet of the fish. For example, trout that have been feeding on crustaceans tend to be more flavorful than those feeding primarily on insect life. Additionally, they provide a good fight when caught with a hook and line, and are sought after recreationally. Because of their popularity, trout are often raised on fish farms and planted into heavily fished waters, in an effort to mask the effects of overfishing. While they can be caught with a normal rod and reel, fly fishing is a distinctive method developed primarily for trout, and now extended to other species. Farmed trout and char are also sold commercially as food fish.
According to the British Nutrition Foundation, trout contain one of the lowest amounts of dioxins (a type of environmental contaminant) of all oily fishes.^[3]

River fishing

Rainbow trout, Oncorhynchus mykiss

Golden trout, Oncorhynchus aguabonita

Understanding how moving water shapes the stream channel will improve your chances of finding trout. In most streams, the current creates a Riffle-Run-Pool pattern that repeats itself over and over. A deep pool may hold a big brown trout, but rainbows and smaller browns are likely found in runs. Riffles are where you will find small trout, called troutlet, during the day and larger trout crowding in during morning and evening feeding periods.

• Riffles have a fast current and shallow water. This gives way to a bottom of gravel, rubble or boulder. Riffles are morning and evening feeding areas. Trout usually spawn just above or below riffles, but may spawn right in them.

• Runs are deeper than riffles with a moderate current and are found between riffles and pools. The bottom is made up of small gravel or rubble. These hot spots hold trout almost anytime, if there is sufficient cover.

• Pools are smoother and look darker than the other areas of the stream. The deep, slow-moving water generally has a bottom of silt, sand, or small gravel. Pools make good midday resting spots for medium to large trout.^[4]

• It is recommended that when fishing for trout, that the fisher(s) should use line in the 4-8 lb test for streamfish, and stronger line with the same diameter for trout from the sea or from a large lake, such as Lake Michigan. It is also recommended to use a hook size 8-5 for trout of all kind. Trout also find salmon eggs, worms, minnows, cut bait, or corn attractive with corn and the occasional marshmallow especially attractive to farm raised trout.