(Salmo trutta)
Conservation • Invasive/Noxious • Description • Habitat • Ecology • Distribution • Taxonomy
Description |
Brown trout is an exotic, invasive fish. It is native to Europe and North Africa. It was first introduced in New York and separately in Newfoundland Canada in 1883. Since then, it has been introduced several times into several locations in North America. It now occurs throughout the United States and to a lesser extent across southern Canada. It is common in Minnesota. Brown trout is a highly adaptable fish found in streams, rivers, and lakes. Adults prefer deep, moderate to slow streams, but it spawns in shallow, fast-moving streams and that is where the juveniles are found. It is a hardy fish that can withstand warmer and cloudier water than rainbow trout. Trout streams in southern Minnesota have mostly brown trout, and trout streams in northern Minnesota have mostly rainbow trout. The size of an adult fish depends on both its age and its habitat. Stream brown trout are usually 10″ to 15″ (25 to 38 cm) long and weigh 3½ to 5½ lbs. (1.6 to 2.5 kg), though they can get much bigger. Lake brown trout are much bigger. The Minnesota state record brown trout is 16¾ lbs. (7.56 kg). The head is small and pointed. The mouth is large, and it has well developed teeth all along both jaws. The upper jaw (maxilla) extends beyond the eye. The lower jaw is whitish, and it has no gray or black markings. In the gills, there are usually 10 curved bones (branchiostegal rays) supporting the gill membranes. The body is long, slender, and tapered. The row of pores that runs from the gills to the tail (lateral line) is faint but visible. The scales are small. There are more than 20 rows of scales above the lateral line, and 120 to 130 scales on the lateral line. The ground color is brown or yellowish brown. The upper body is densely covered with small dark spots surrounded by broad pale halos. The largest dark spot is smaller than the diameter of the eye. There are numerous dark spots below the lateral line. The lower body has several red spots that are also surrounded by pale halos. There are 3 or 4 dorsal spines and 3 or 4 anal spines. The adipose fin has a red margin. The anal fin usually has 10 to 12 rays. The tail (caudal) fin is symmetrical, with two lobes of equal proportion. It either has no black spots, or there are poorly developed black spots only on the upper lobe. |
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Sources Nonindigenous Aquatic Species (NAS) information resource for the United States Geological Survey |
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12/12/2024 | ||
Occurrence |
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Locally common |
Taxonomy |
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Superclass |
Actinopterygii (ray-finned fishes) |
Class |
Actinopteri |
Subclass |
Neopterygii |
Infraclass |
Teleostei (teleost fishes) |
Clade |
Osteoglossocephalai |
no rank |
Clupeocephala |
Cohort |
Euteleostei (= Euteleosteomorpha) |
Superorder |
Protacanthopterygii |
Order |
Salmoniformes (salmons, pikes, and mudminnows) |
Suborder |
Salmonoidae (salmons, trouts, and whitefishes) |
Family |
Salmonidae (salmons, trouts, and whitefishes) |
Subfamily |
Salmoninae (salmons and trouts) |
Genus |
Salmo (Atlantic salmons and trouts) |
Subordinate Taxa |
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Many subspecies and varieties of Salmo trutta have been described. Brown trout has been introduced into several locations in North America from several locations in Europe. Those introductions included sea forms, lake forms, and river forms. It is believed by some that the imported subspecies have cross-bred, producing what has become a single North American subspecies Salmo trutta ssp. trutta. Some sources recognize one subspecies and up to 19 varieties (GBIF). Some sources recognize four subspecies (NCBI and iNaturalist). Some sources classify three of those varieties as morphs (Wikipedia). Most sources do not recognize any infraspecific taxa in North America (ITIS, NatureServe, Catalog of Life, and Discover Life). |
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Aral Sea trout (Salmo trutta ssp. aralensis) lake brown trout (Salmo trutta ssp. lacustris) river brown trout (Salmo trutta ssp. fario) sea brown trout (Salmo trutta ssp. trutta) |
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Synonyms |
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Fario argenteus Fario lacustris Fario trutta Salar ausonii Salar ausonii var. parcepunctata Salar ausonii var. semipunctata Salar bailloni Salar gaimardi Salar spectabilis Salmo abanticus Salmo albus Salmo albus Salmo brachypoma Salmo caecifer Salmo cambricus Salmo cornubiensis Salmo cumberland Salmo eriox Salmo estuarius Salmo fario Salmo fario loensis Salmo fario major Salmo fario var. forestensis Salmo faris var. forestensis Salmo gadoides Salmo gallivensis Salmo illanca Salmo islayensis Salmo lacustris Salmo lacustris rhenana Salmo lacustris romanovi Salmo lacustris septentrionalis Salmo lemanus Salmo levenensis Salmo mistops Salmo montana Salmo orcadensis Salmo orientalis Salmo oxianus Salmo phinoc Salmo polyosteus Salmo rappii Salmo saxatilis Salmo spurius Salmo stroemii Salmo sylvaticus Salmo taurinus Salmo trutta aralensis Salmo trutta ciscaucasicus Salmo trutta ezenami Salmo trutta fario Salmo trutta lacustris Salmo trutta oxianus Salmo trutta trutta Salmo truttula Salmo venernensis Trutta fario Trutta fluviatilis Trutta lacustris Trutta marina Trutta salmanata Trutta salmonata Trutta trutta Trutta variabilis |
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Common Names |
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brown trout |
Glossary
Lateral line
In fish: A faint row of pores along a fish’s body from the gills to the tail. It allows the fish to detect movement, vibrations, and pressure gradients in the water around them.
Maxilla
The upper jaw of a fish formed by two bones and having teeth attached to it.
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Other Videos |
Ecosystem in a modified river - Wild Salmo trutta (Brown trout) - Natural habitat ᴴᴰ |
About
Jan 24, 2017 Location: Andorra Filmed in January, at the beginning of the spawning season of trout. The spawning behaviour of brown trout is similar to that of the closely related Atlantic salmon. Mediterranean native brown trout in the Pyrenees. |
Brown trout (Salmo trutta) ⁴ᵏ ᵁˡᵗʳᵃ ᴴᴰ |
About
Dec 31, 2017 The native range of brown trout extends from northern Norway and White Sea tributaries in Russia in the Arctic Ocean to the Atlas Mountains in North Africa. The western limit of their native range is Iceland in the north Atlantic, while the eastern limit is in Aral Sea tributaries in Afghanistan and Pakistan. The fish is not considered to be endangered, although, in some cases, individual stocks are under various degrees of stress mainly through habitat degradation, overfishing, and artificial propagation leading to introgression. Increased frequency of excessively warm water temperatures in high summer causes a reduction in dissolved oxygen levels which can cause "summer kills" of local populations if temperatures remain high for sufficient duration and deeper/cooler or fast, turbulent more oxygenated water is not accessible to the fish. This phenomenon can be further exacerbated by eutrophication of rivers due to pollution—often from the use of agricultural fertilizers within the drainage basin. Overfishing is a problem where anglers fail to identify and return mature female fish into the lake or stream. Each large female removed can result in thousands fewer eggs released back into the system when the remaining fish spawn. Another threat is other introduced organisms. For example, in Canada's Bow River, a non-native alga Didymosphenia geminata—common name rock snot (due to appearance)—has resulted in reduced circulation of water amongst the substrate of the river bed in affected areas. This, in turn, can greatly reduce the number of trout eggs which survive to hatch. Red List Category & Criteria: Least Concern Current Population Trend: Unknown English - Brown Trout, Sea Trout Spanish - Trucha común, Trucha marrón, Reo Sea trout in the UK and Ireland have many regional names, including sewin (Wales), finnock (Scotland), peal (West Country), mort (North West England), and white trout (Ireland). |
Underwater footage of Brown Trout spawning (Salmo trutta). Tření Pstruha obecného potočního. |
About
Feb 26, 2023 Underwater footage of spawning Brown Trout (Salmo trutta morpha fario). |
Created: 12/12/2024 Last Updated: © MinnesotaSeasons.com. All rights reserved. |