Trout

Trout
For other uses, see Trout (disambiguation).
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. 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

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:

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. The pelvic fins sit well back on the body, on each side of the anus. The swim bladder is connected to the esophagus, allowing for gulping or rapid expulsion of air, a condition known as physostome. Unlike many other physostome fish, the trout do not use their bladder as an axillary device for oxygen uptake, relying solely on their gills.

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

Trout fillet.

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, especially farm-raised ones, tend to like salmon eggs, worms, minnows, cut bait, corn, or marshmallows.

See also

References

  1. ^ "What's an oily fish?". Food Standards Agency. 2004-06-24. http://www.food.gov.uk/news/newsarchive/2004/jun/oilyfishdefinition. 
  2. ^ Peter Landergren, Spawning of anadromous rainbow trout, Oncorhynchus mykiss (Walbaum): a threat to sea trout, Salmo trutta L., populations?, Fisheries Research 40(1), 1999, pp. 55-63.
  3. ^ "Fish". British Nutrition Foundation. http://www.nutrition.org.uk/home.asp?siteId=43&sectionId=593&parentSection=322&which=. 
  4. ^ Troutlet.com: How to Read a River when Trout Fishing
  • Trout and Salmon of North America, Robert J. Behnke, Illustrated by Joseph R. Tomelleri, The Free Press, 2002, hardcover, 359 pages, ISBN 0-7432-2220-2
  • Trout Science, Troutlet.com, 2000, knowledgebase article

External links


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Look at other dictionaries:

  • Trout — (trout), n. [AS. truht, L. tructa, tructus; akin to Gr. trw kths a sea fish with sharp teeth, fr. trw gein to gnaw.] 1. (Zo[ o]l.) Any one of numerous species of fishes belonging to {Salmo}, {Salvelinus}, and allied genera of the family… …   The Collaborative International Dictionary of English

  • trout — [trout] n. pl. trout or trouts [ME troute < OE truht < LL tructus, tructa < Gr trōktēs, kind of fish < trōgein, to gnaw: see TROGLODYTE] 1. any salmonid; esp., any of various food and game fishes that are usually speckled and found… …   English World dictionary

  • Trout — ist der Familienname von: Jack Trout, US amerikanischer Unternehmer und Eigentümer des strategischen Marketingbüros Trout Partners Walter Trout (* 1951), US amerikanischer Komponist, Gitarrist und Sänger Siehe auch: Trout (Louisiana), Ort in den… …   Deutsch Wikipedia

  • trout — trout·er; trout·less; trout·let; trout; trout·ling; …   English syllables

  • trout — [traut] n ↑fin, ↑gill [Date: 1000 1100; : Late Latin; Origin: tructa type of fish with sharp teeth, from Greek, from trogein to bite ] 1.) plural trout [U and C] a common river fish, often used for food, or the flesh of this fish 2.) …   Dictionary of contemporary English

  • trout — O.E. truht trout, in part from O.Fr. truite, both from L.L. tructa, perhaps from Gk. troktes a kind of sea fish, lit. nibbler, from trogein to gnaw, from PIE root *tere (see THROW (Cf. throw)). In late 17c. slang, trusty trout was used in a sense …   Etymology dictionary

  • trout — ► NOUN (pl. same or trouts) ▪ an edible fish of the salmon family, chiefly inhabiting fresh water. ● old trout Cf. ↑old trout ORIGIN Old English, from Greek tr gein gnaw …   English terms dictionary

  • trout — [ traut ] (plural trout) noun count a fish that lives in rivers and lakes a. uncount this fish eaten as food …   Usage of the words and phrases in modern English

  • trout — is the same in the plural, except that old trout (a depreciatory slang term for an old woman) has the plural form old trouts …   Modern English usage

  • trout — troutless, adj. troutlike, adj. /trowt/, n., pl. (esp. collectively) trout, (esp. referring to two or more kinds or species) trouts. 1. any of several game fishes of the genus Salmo, related to the salmon. Cf. brown trout, cutthroat trout …   Universalium

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