Arctic charr (Salvelinus alpinus)
|Also known as:||Arctic char, Charr|
|Size||Length: up to 107 cm (2)|
|Weight||up to 15 kg (2)|
The Arctic charr is classified as Least Concern on the IUCN Red List (1).
The Arctic charr (Salvelinus alpinus) is a large, cold-water fish whose physical appearance is highly variable between and within populations (3). Its body colour is largely dependent on the location, season and sexual maturity of the individual (2), but is generally silver-white, sometimes becoming bright orange on the underside and fins, especially during the spawning season (4). This vivid orange colouration is mostly seen in the male Arctic charr, although it may also be evident in the female (2) (4). The intensity of the orange-red colour is thought to be related to the nutrition, health and foraging ability of the individual (5), deriving from pigments gained from the diet (6).
The pectoral and anal fins of breeding Arctic charr are red (2), with a narrow white margin on the forward-facing edges (2) (4) (7). The caudal fin is slightly forked and has a yellow-gold border (4) (7). The fins of the juvenile are paler than in the adult (2).
Non-breeding Arctic charr do not usually exhibit the bright colouration and are much paler in comparison (4), with a bronze-green upperside, pale sides and a pale belly (2) (7). The sides and back of the body of breeding and non-breeding individuals are patterned with multiple spots ranging in colour from white to red (2) (4) (7). The largest spots are usually along the lateral line, which runs down each side of the body (2).
In addition to its varied colouration, the Arctic charr is also highly variable in size and shape (3). However, most individuals have a slightly rounded, elongated body with a large mouth and an upwardly protruding lower jaw (4) (8).
Some scientists recognise a number of subspecies of Arctic charr (3).
The Arctic charr has a circumpolar distribution (7), stretching from Alaska to northern Russia, including Canada, Greenland, Norway and Iceland. There are isolated populations in the northern United Kingdom, Scandinavia and Finland, as well as landlocked populations in Canada and the United States (2).
The Arctic charr inhabits freshwater lakes and rivers, as well as estuaries and oceans (2) (8), where there is cold, clear water (2). Populations in the ocean remain close to the coastline (1) (2). In rivers, the Arctic charr is found in deep runs and pools (2).
Migratory behaviour in the Arctic charr is highly variable (1). Certain populations make annual migrations from the sea to a freshwater lake or river. Other populations are sedentary and remain within their freshwater habitat throughout their lives (1) (2). Riverine populations have been known to perform migrations within the river system or may also be sedentary (1).
Migratory Arctic charr usually reach sexual maturity and spawn for the first time at four to ten years old, whereas lake-dwelling individuals spawn after two to five years (1). After this period, the Arctic charr only spawns every two to four years, once the reproductive organs have redeveloped from the last season (3). Most individuals will only spawn around three times throughout their life (3).
The breeding behaviour of the Arctic charr varies greatly between populations, with some individuals spawning in freshwater lakes after migrating from the sea, and riverine populations finding areas with slow currents (1) (2). Spawning usually takes place onto a rocky or gravelly substrate (1) (2) (9). The male Arctic charr sometimes build a nest, which can be up to two or three metres in diameter, where it spawns with several females (1). Males can be very territorial during the spawning season (1).
In lake-dwelling populations, spawning occurs between autumn and early winter (1), with young fish usually emerging the following spring (9). However, different stocks are known to spawn at different times throughout the year (1). Once hatched, the young fish will remain hidden within the gravel and stones, only leaving to feed on insect larvae and small crustaceans (9).
The diet of the Arctic charr is mainly composed of small fish, amphipods, planktonic crustaceans, molluscs and insects (2). When feeding at sea, fish and larger invertebrates are taken (1) (3).
The Arctic charr is able to withstand freezing conditions and can gain weight in this environment, where other species would lose weight (3) (7). This species is known to form dense shoals in deep water (6).
The Arctic habitat of the Arctic charr is under threat due to global warming, which is increasing the temperature of freshwater lakes, rivers and oceans. This species is the most temperature-sensitive species in the Salmonidae family, and temperature increases may compromise its future survival (8) (10) (11). The freshwater habitats of the Arctic charr are also susceptible to pollution, eutrophication and acidification, which have a negative effect on the fish which inhabit these areas (11).
Introduced species also pose a threat to the Arctic charr (3) (11), outcompeting it for living and spawning areas, as well as altering the abundance of prey species such as phytoplankton. The zebra mussel (Dreissena polymorpha) in Northern Ireland is just one example of how an invasive species can affect the Arctic charr, having colonised the hard surfaces in the Shannon-Erne waterway, potentially having a negative effect on areas used by the Arctic charr as spawning grounds (11).
The Arctic charr is a highly prized sports fish, and is also caught and sold for food, meaning that its population could come under threat in the future due to overfishing (2) (3) (9). The infrequency of spawning in the Arctic charr may also make it more susceptible to overfishing (3).
In Northern Ireland, certain areas the Arctic charr inhabits have been designated as Areas of Special Scientific Interest and Special Areas of Interest, which offer protection to the habitat of this species. In Northern Ireland, there is also an action plan which aims to maintain or restore certain lakes which the Arctic charr is known to live in (11).
More research is necessary to manage the conservation of the Arctic charr (12). Imposing fishing restrictions may also be an appropriate method for the conservation of this species (3).
Find out more about the Arctic charr and salmonid conservation:
FishBase - Arctic charr:
IUCN/SSC Salmonid Specialist Group:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
- Amphipods: a group of small shrimp-like crustaceans that includes sandhoppers, beach hoppers, and water lice.
- Anal fin: in fish, an unpaired fin on the under surface of the fish, behind the anus.
- Caudal fin: the tail fin of a fish.
- Crustaceans: diverse group of animals with jointed limbs and a hard external skeleton, characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.
- Eutrophication: a process in which a water body is enriched with excessive nutrients (such as nitrogen and phosphorus) resulting in the excessive growth of aquatic plants and the depletion of oxygen, creating unfavourable conditions for other organisms, such as fish.
- Invertebrates: animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.
- Larva: immature stage in an animal’s lifecycle, after it hatches from an egg and before it changes into the adult form. Larvae are typically very different in appearance to adults; they are able to feed and move around but are usually unable to reproduce.
- Lateral line: a row of receptors that can detect movement via vibrations in water. The receptors are typically embedded in the skin, and in fish they form a line along the sides of the body.
- Molluscs: a diverse group of invertebrates, mainly marine, that have one or all of the following: a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.
- Pectoral fins: in fish, the pair of fins that are found on either side of the body just behind the gills. They are generally used for balancing and braking.
- Phytoplankton: aquatic plants, usually tiny, that drift passively with water movements.
- Planktonic: of or relating to plankton; aquatic organisms, usually tiny, that drift passively with water movements. Includes phytoplankton (plants), zooplankton (animals), or other organisms such as bacteria.
- Spawning: the production or depositing of eggs in water.
- Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
- Territorial: describes an animal, a pair of animals or a group that occupies and defends an area.
IUCN Red List (February, 2012)
FishBase - Arctic charr (February, 2012)
- Behnke, R.J. (2002) Trout and Salmon. The Free Press, New York.
Frost, F.O. (2001) Arctic Management Plan. Department of Inland Fisheries and Wildlife Division of Fisheries and Hatcheries, Maine. Available at:
- Martinkappi, J.B., Kekäläinen, J., Shatilova, Y. and Parkkinen, J. (2009) Carotenoid Concentration of Arctic charr (Salvelinus alpinus L.) from spectral data. In: Blanc-Talon, J., Philips, W., Popescu, D. and Scheunders, P. (Eds.) (2009) Advanced Concepts for Intelligent Vision Systems. 11th International Conference, ACIVS 2009, Bordeaux, France, September/October 2009, Proceedings.Springer Verlag, Berlin, Germany.
Esk Rivers and Fisheries Trust - Scotland’s Arctic Charr (March, 2012)
- Keyse, M.D. (2006) Patterns in Diet and Trophic Position of Lake Trout (Salvelinus namaycush)and Arctic Char (Salvelinus alpinus)Populations When Coexisting and in Isolation in Arctic Alaskan Lakes. MSc thesis, University of North Carolina, USA.
- Ainsworth, M. (2009) Fish and Seafood. Delmar, New York.
- Le François, N., Jobling, M., Carter, C. and Blier, P. (2010) Finfish Aquaculture Diversification. CABI, Oxfordshire, UK.
- Baroudy, E. and Elliott, J.M. (1996) The critical thermal limits for juvenile Arctic charrSalvelinus alpinus. Journal of Fish Biology,45: 1041-1053.
Department of the Environment Northern Ireland (2002) Northern IrelandBiodiversityStrategy. Environment and Heritage Service, Belfast. Available at:
- Maitland, P.S., Winfield, I.J., McCarthy, I.D., Igoe, F. (2007) The status of Arctic charr Salvelinus alpinus in Britain and Ireland. Ecology of Freshwater Fish, 16: 6-19.