Salvelinus fontinalis

Common names 

in English 

Brook trout [brook char(r)] (Salvelinus fontinalis) 

Photo Eric Engbretson, lllustration Duane Raver, published by U.S. Fish and Wildlife Service. 

Brook trout. American brook trout. Common (eastern) brook trout. 

Brook char(r). Brookie. Speckled trout. Eastern speckled trout. 

Speckled char(r). Aurora trout. Sea trout. Breac. Mountain trout. 

Mud trout. Lord-fish. Humpbacked trout. Squaretail. Whitefin. 

… and in other languages Danish: Kildeørred. Dutch: Bronforel. Finnish: Puronieriä. 

French: Omble de fontaine. Saumon de fontaine. Truite mouchetée. 

German: Amerikanischer Bachsaibling. Bachsaibling. 

Icelandic: Lindableikja. Inuit: Aanak. Ana. Âna. Aanaatlik. Anakleq. 

Anokik. Anuk. Iqaluk, Iqaluk tasirsiutik. Italian: Salmerino di Torrente. 

Japanese: Kawamasu. Latvian: Avota palija. Lithuanian: Amerikine 

palija. Norwegian: Bekkerøue. Polish: Pstrag zródlany. 

Portuguese: Truta-das-fontes. Russian: Amerikanskiy golets. 

Amerikanski goletz. Spanish: Salvelino. Trucha de arroyo. 

Swedish: Amerikansk bäckröding. Bäckröding. Källax. 

Scientific name Salvelinus fontinalis 

Organism group Ray-finned fishes (Actinopterygii). Salmons (Salmoniformes). 

Salmonids (Salmonidae). 

Size and appearance This species resembles both Arctic char (Salvelinus alpinus) and brown 

trout (Salmo trutta), but, unlike Arctic char, has spots on its dorsal 

and caudal fins, and, unlike brown trout, has light-coloured spots on 

its body. Adult brook trout living in fresh waters are green to dark

May be confused with – 

brown, almost black, on their back and sides. The back and upper 

sides have yellow and yellowish green worm-like markings or 

marbling. The lower part of the back has small yellow or yellowish 

green and/or red spots. The dorsal and caudal fins are a darker 

brownish green, while the other fins are reddish brown, often with a 

white and black border on the leading edge. During the spawning 

period, the colours are intensified, the belly of the male turning a 

characteristic deep orange-red. 

Brook trout sometimes migrate to the sea and remain there for a time 

before returning to fresh waters. Such fish are popularly known as 

“salters”. Adults in a saltwater environment have silvery sides, a dark 

blue or green back and a whitish belly. They may have pale red spots 

on the sides and on the white borders of their fins. On returning to 

fresh waters, they regain their earlier colours. 

Unlike Arctic char and lake trout (Salvelinus namaycush), brook trout 

rarely live for more than 9–10 years. Adults can grow to a length of 

about 80 cm, but usually reach just 30–45 cm. In Swedish waters, 

adult brook trout generally weigh just under 1 kg, although in fish 

farms they can reach a weight of 2–3 kg. In their native range, brook 

trout can be considerably larger, with a reported maximum weight of 

over 9 kg. 

Geographical origin Eastern North America: much of Canada, from Newfoundland to the 

western side of Hudson Bay; and in the United States, south through 

Massachusetts and along the Appalachians, and west to Minnesota. 

First observed in 

Swedish waters 

Occurrence in Swedish 

seas and coastal areas 

Occurrence in 

other sea areas 

Probable means 

of introduction 

Habitat(s) in which 

species occurs 

The species was first introduced into Sweden in 1892, for stocking in 

mountain waters. 

Brook trout that have escaped from fish farms have been caught in the 

Baltic off the Uppland coast. (The species may not be stocked in 

Swedish waters without a special permit.) 

Brook trout is a very popular species among anglers, and has 

consequently been introduced into countries throughout the world for 

stocking purposes. It was first imported to Europe in 1884, and is now 

to be found in natural and artificial waters across much of that 

continent, including the Nordic countries (Denmark, Finland, Norway 

and Sweden), the Baltic Sea area and the British Isles. The species has 

also been introduced into many other regions, including western North 

America, many countries in South America, Asia and Africa, and New 

Zealand and Australia. 

Aquaculture: cultivation and stocking. 

Salvelinus fontinalis requires an undisturbed environment, and can 

accordingly serve as a sensitive indicator of water pollution and 

oxygen depletion (it avoids cloudy water with low levels of oxygen). 

The species has become relatively tolerant of low pH, and adults can 

withstand pH levels as low as 5.0, but are unable to cope if the water 

becomes more acidic than that. 

The brook trout often lives alone in cold (preferably 10–18°C), clear, 

well-oxygenated rivers and small streams, but is also found in lakes 

together with many other fish species. It frequently swims in shallow 

water along the shoreline, but can be found at greater depths as well.

The species can also cope with warmer water, but in that case the 

water must be well oxygenated, with a temperature of 25°C at the 

very highest, and preferably no higher than 20°C. Brook trout are 

sometimes found in small ponds and springs. In Swedish freshwater 

systems where brown trout are also present, brook trout retreat to the 

headwaters of the system. In many cold lakes and watercourses in 

central and northern Sweden, the species lives in competition with 

brown trout. In its native range in North America, the brook trout 

shows considerable ecological similarities to the brown trout of Europe, 

spending its early years in tributary streams before becoming a lakedwelling 

predator, often feeding on Arctic char. 

In spring, brook trout may migrate between fresh waters and the sea, 

spending a short time (at most around three months) in the marine 

environment. These migrations are limited, however: the fish stay 

relatively close to river mouths, venturing no more than a few 

kilometres out to sea. Brook trout may run to the sea to avoid streams 

and rivers in which the water has become too warm, or because 

conditions have become unfavourable in some other respect 

(competition, a shortage of food). In some cases, they overwinter in 

estuaries and migrate along the coast. Migrations do not involve all the 

fish in a population, nor do they occur every year. Brook trout that do 

migrate, however, usually grow larger and live longer than strictly 

freshwater individuals. 

Brook trout feed on insects, worms, molluscs, crustaceans, amphibians 

and fish. 

Ecological effects In Swedish waters, the brook trout has established wild populations, 

often in small headwater streams, and may affect local populations of 

brown trout. 

Non-native salmonids that are stocked in Swedish waters may form 

hybrids with native species. Often these hybrids are fertile, which 

means that they are able to reproduce in the wild. This is true, for 

example, of “sparctic char” (also known as “sparctic trout” or “spar”, a 

cross between brook trout and Arctic char) and “splake” (brook trout 

and lake trout). 

The name splake comes from speckled trout + lake trout. This hybrid 

is also known as wendigo. The fact that sparctic char, splake, and the 

third hybrid combination, “larctic char” (a cross between lake trout and 

Arctic char), are able to reproduce naturally shows that Salvelinus 

species may be involved in the active formation of new species. 

American studies have found that splake grow faster than brook trout, 

live longer, and often feed on fish (including pike) that could otherwise 

pose a threat to brook trout. 

In discussions about the genetic effects of non-native species finding 

their way into Swedish waters, the focus has been very much on 

salmonids, since such fish are farmed and stocked on a large scale 

and, what is more, hatchery-reared fish quite often escape into the 

wild. 

In this context, “genetic effects” means changes in the genetic makeup 

of native species that can result from the incorporation of genes 

from the new organisms. The risks associated with introducing nonnative 

populations or genes into the natural environment come under 

three main headings: extinction, hybridization, and loss of genetic 

variation. 

When closely related species or distinct populations of a single species

interbreed, hybridization can result. This can happen if individuals of a 

non-native species mate with individuals of a native one. The offspring 

exhibit characteristics differing, to a greater or lesser degree, from 

those of the native parent. In the long term, this may result in wild 

populations of a species losing some of their ability to adapt to their 

environment. Stocked fish, for example, are less well adapted to their 

new environment than the wild fish with which they mix. 

At worst, the introduction and spread of non-native populations or 

genes may drive native species to extinction. This may happen either 

because the native species is outcompeted and displaced, or because 

of genetic changes in the offspring (hybrid) of the alien and native 

species which mean that the offspring is unable to survive. If the 

hybrid is fertile, however, the next step may be an exchange of genes 

with the parent population. Non-native genetic material will then be 

incorporated into the native species, and in the long run the effect of 

this could be to eliminate local variants. 

Mixing of non-native species or genetic variants with local populations 

may have implications for Sweden’s populations of Arctic char, Atlantic 

salmon (Salmo salar) and brown trout. Over time, native salmonid 

stocks have adapted to conditions in their particular lakes and rivers, 

gradually becoming genetically distinct from every other stock of the 

same species. The loss of such local adaptations may leave a 

population less well equipped to survive. 

Stocking of hatchery-reared fish can also lead to inbreeding 

depression. This occurs when closely related individuals mate with one 

another, and may result in offspring that are unviable or have difficulty 

surviving. 

Other effects Brook trout is a very popular species among anglers, and is therefore 

of considerable economic significance. It is also a food fish, and is 

often sold across the fish counters of Stockholm as röding (“char”). 

Brook trout are cultured for use as pond fish, for direct sale as a food 

fish, and for stocking for recreational fisheries. 

FIND OUT MORE 

• North European and Baltic Network on Invasive Alien Species: Salvelinus fontinalis 

http://www.nobanis.org/speciesInfo.asp?taxaID=700 

• Baltic Sea Alien Species Database: Salvelinus fontinalis 

http://www.ku.lt/nemo/directory_details.php?sp_name=Salvelinus+fontinalis 

• Alien species in Poland: Speckled brook trout 

http://www.iop.krakow.pl/ias/species.asp?198 

• ICES Working Group on Environmental Interactions of Mariculture 

http://www.ices.dk/iceswork/wgdetail.asp?wg=WGEIM 

• 125 kB: EU-kommissionen: A strategy for the sustainable development 

of European aquaculture 

http://www.europa.eu.int/eur-lex/en/com/cnc/2002/com2002_0511en01.pdf 

• 357 kB: EU-kommissionen: Farmed fish and welfare 

http://ec.europa.eu/fisheries/publications/farmedfish_en.pdf 

• Federation of Europan Aquaculture Producers 

http://www.feap.info/feap 

• European Aquaculture Society 

http://www.easonline.org 

• FishBase: Salvelinus fontinalis 

http://www.fishbase.org/Summary/SpeciesSummary.php?id=246 

• European Nature Information System Database (EUNIS): Salvelinus fontinalis 

http://eunis.eea.europa.eu/species-factsheet.jsp?idSpecies=9977&idSpeciesLink=9977 

• Ittiofauna.org: Il Salmonidi (webbplats om bl.a. laxfiskar i Europa)

http://www.ittiofauna.org/webmuseum/pesciossei/salmoniformes/salmonidae/salmonidae.htm 

• Alaska Department of Fish & Game: Brook trout 

http://www.adfg.state.ak.us/pubs/notebook/fish/b^trout.php 

• Nova Scotia Fisheries and Aquaculture: Speckled trout 

http://www.gov.ns.ca/nsaf/sportfishing/species/spec.shtml 

• University of Toronto: Brook trout 

http://www.zoo.utoronto.ca/manuesteve/UTbrooktrout.html 

• Ontario Federation of Anglers and Hunters: Ontario's fish: Brook trout 

http://www.ofah.org/fishing/description.cfm?Species=Cold_Water&FishID=18 

• Canadian Sportfishing: Brook trout 

http://www.canadian-sportfishing.com/Tips&Techniques/Species_Info/Default1.asp?Species_Name=BROOK TROUT 

• Trout unlimited: Back the Brookie 

http://www.brookie.org 

• U.S. Fish and Wildlife Service: Coaster brook trout 

http://www.fws.gov/midwest/Fisheries/topic-coasterbrooktrout.htm 

• U.S. Fish and Wildlife Service: Brook trout 

http://images.fws.gov/default.cfm?CFID=5641494&CFTOKEN=95949698 

• National Wildlife Foundation: Salvelinus fontinalis 

http://www.enature.com/fieldguides/detail.asp?shapeID=994&curGroupID=3&lgfromWhere=&curPageNum=15 

• Mt. Baker-Snoqualmie National Forest Pacific Northwest Fisheries Program: 

Eastern Brook Trout 

http://www.fs.fed.us/r6/fishing/forests/fishresources/mtbsno_coldwater.html#eastbrook 

• Wisconsin Sea Grant: Brook trout 

http://www.seagrant.wisc.edu/greatlakesfish/brooktrout.html 

• Virginia Fish and Wildlife Information Service: Virtual Aquarium: Salvelinus fontinalis 

http://www.cnr.vt.edu/efish/families/brktrout.html 

• US Geological Survey: NAS-Nonindigenous Aquatic Species: Salvelinus fontinalis 

http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=939 

• Cornell University: Fishes of New York: Brook trout 

http://fish.dnr.cornell.edu/nyfish/Salmonidae/brook_trout.html 

• NatureServe Explorer: Salvelinus fontinalis 

http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Salvelinus fontinalis 

• Trouts and Seasons of The Mountain Village: Salvelinus fontinalis 

http://www.amago.jp.lv/trout/trout32.html 

Splake 

• US Geological Survey: NAS-Nonindigenous Aquatic Species: Salvelinus fontinalis x namaycush 

http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=940 

• Ontario Federation of Anglers and Hunters: Ontario's fish: Splake 

http://www.ofah.org/fishing/description.cfm?Species=Cold_Water&FishID=24 

• State of Maine: Splake Fact Sheet 

http://www.state.me.us/ifw/fishing/fishidentification/splake.htm 

• Wisconsin Department of Natural Resources: Lake Trout--Splake--"Coaster" Brook Trout comparison 

http://www.dnr.state.wi.us/org/gmu/superior/Fish/Fish ID.htm 

Photo: Eric Engbretson 

Illustration: Duane Raver 

IMAGES CREDITS 

Images are published under public domain by U.S. Fish and Wildlife Service, Digital Library 

Service 

http://images.fws.gov 

• This factsheet on Salvelinus fontinalis was created on 30 November 2006 

• First update: 15 January 2007 

• Translated by Martin Naylor on 22 January 2007

Salvelinus fontinalis

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