Arctic char can be landlocked, anadromous or semi-anadromous depending on location. Arctic char that are located above 65 degrees north latitude are anadromous. For the first one to nine years of age anadromous arctic char live in freshwater. In the summer mature anadromous arctic char migrate to the sea where they spend their time in the coastal and intertidal areas. After the summer arctic char return to the frozen lakes, migrating through estuarine and brackish water. Most arctic char spend their time between 0-1 meters deep but some will go up to 3 meters deep from the water surface. The maximum depth arctic char have been recorded is 16 meters from the water surface. (Freyhof and Kottelat, 2008; Rikardsen, et al., 2007)
Arctic char have a distinct size dimorphism, dwarf and giant. Male and female arctic char are the same size. In Lake Store Skardørsjø, Finstad et al. (2006) recorded giant arctic char up to 60.6 cm and dwarf arctic char at 9.2 cm. The study recorded giant arctic char with masses from 0.144-1.978 kg and dwarf char mass ranged from 0.006-0.04 kg. The appearance of arctic char differs between populations. The dorsal side of the arctic char is dark in color while the ventral varies from red, yellow, and white depending on location. In the spawning season the red becomes more intense, with males exhibiting brighter coloration. Breeding arctic char have red pectoral and anal fins and yellow or gold borders on the caudal fin. The fin color of juvenile arctic char is paler than that of adults. In male nonanadromous arctic char the kype is either not present or difficult to discern. (Finstad, et al., 2006; Morton, 1965; Ortenburger, et al., 1996)
Egg development of arctic char happens in three stages: cleavage, epiboly, and organogenesis. The cleavage phase begins after fertilization and lasts until the formation of the early embryo. The cells formed during the cleavage phase start to form specialized tissues during the epiboly phase. The organogenesis phase begins when the internal organs begin to occur. Sexual differentiation occurs shortly after hatching and is controlled by the chromosomal configuration of the nucleus in the fertilized egg. A Y and X chromosome will result in a male whereas two X chromosomes result in a female. Morphological sex characteristics are set by hormones released in the alevins (newly spawned char) after hatching. Arctic char growth is indeterminate. At hatching, fry are 25 mm. Fry double in length during their first year, and at 3-5 years they range from 80-150 mm. (Morrow and Dalen, 1980; Pavlov and Osinov, 2008)
In one mating season, male arctic char are polygynous but females are monogamous. Males either guard a female or attempt to sneak-mate with a guarded female. In preparation for spawning, males will establish a territory that they defend. Females will select a location within a male's territory and dig their spawning nest. Males begin courting females by circling around them, then moving beside the females and quivering. Together, the males and females release eggs and milt into the pit area, so fertilization is external. The fertilized eggs are deposited into the gravel. (Morrow and Dalen, 1980; Pavlov and Osinov, 2008)
Arctic char spawn seasonally and in groups. Sexual maturity in arctic char ranges from 4 years to 10 years old, usually when they reach around 500-600 mm in length. Gulseth and Nilssen (2001) recorded a mean age of first time, large resident, anadromous spawners of 9.7 years for males and 10.3 for females. Some arctic char do not reach sexual maturity until they are 15 years old. Most populations spawn in the fall between September and December, though there are some landlocked populations that spawn in spring, summer or winter. Arctic char generally spawn once every other year, while some individuals only spawn every 3-4 years. Dominant males are territorial, attracting and guarding females. Males usually reproduce with more than one female in a mating season. Females can lay anywhere between 2,500 and 8,500 eggs which the males then externally fertilize. Time to hatching varies but usually occurs between 2-3 months, with the longest being 5 months. Hatching mass varies within populations. A study by Lemieux et al. (2003) found that arctic char ranged between 0.04-0.07 g upon hatching. Hatchlings are immediately independent of parents at hatching. (Egeland and Rudolfsen, 2016; Gulseth and Nilssen, 2001; Lemieux, et al., 2003; Morrow and Dalen, 1980; Pavlov and Osinov, 2008)
Arctic char do not provide parental care post-spawning. The entire commitment is limited to nest-building by the females and territorial guarding of the area by males for as long as spawning continues. (Eilertsen, et al., 2009; Sigurjónsdóttir and Gunnarsson, 1989)
Arctic char are motile and natatorial. They are a migratory species that are social or found in groups during migration. Migration to the sea occurs early in the summer from mid-June to mid-July, where they spend roughly 50 days then return to the river. Arctic char migrate annually to the sea. Arctic char generally reproduce and overwinter in freshwater. They communicate with their olfactory senses when spawning. Males release a pheromone that attract ovulated females. During spawning season males are solitary and territorial. Dominance is maintained by the larger males. Arctic char have both diurnal and nocturnal feeding activity. Fish in the Family Salmonidae are regarded as visual feeders. Arctic char have been observed relying on taste and tactile stimulus rather than vision. Arctic char choose water scented with their siblings odor over water scented by an arctic char that was not their sibling. (Björnsson, 2001; Dutil, 1986; Egeland and Rudolfsen, 2016; Freyhof and Kottelat, 2008; Linzey, 2011; Morrow and Dalen, 1980; Olsén, et al., 2002; Rikardsen, et al., 2007; Salisbury, et al., 2018; Sveinsson and Toshiaki, 2000)
Arctic char home ranges have not been recorded. Territory size of the arctic char increases with body size and declines with increased food abundance. Territories overlap and are not always exclusively defended. No exact territory sizes have been measured. (Gunnarsson and Steingrímsson, 2011)
Arctic char have a lateral line which helps them detect movements and vibrations within their surroundings. When spawning, arctic char communicate with their olfactory senses. Males release a pheromone that attract ovulating females. Fish in the Salmonidae family have generally been regarded as visual feeders. Björnsson (2001) found that arctic char in Ellidavatn, a lake close to Reykjavík, Iceland, were more likely to rely on taste and tactile stimulus than vision. Arctic char have been observed by Olsén et al. (2002) to choose water scented with their siblings odor over water scented by an arctic char that was not a sibling.
A study by Vilhunen and Hirvonen (2003) found that some juvenile arctic char had highly sensitive recognition of predator odors. Their results indicated that the innate anti-predator behavior of the juvenile fish is finely turned to respond specifically to chemical cues from different fish predators as well as the diets of predators. (Björnsson, 2001; Linzey, 2011; Olsén, et al., 2002; Sveinsson and Toshiaki, 2000; Vilhunen and Hirvonen, 2003)
Arctic char vary their feeding habits depending on location. Arctic char are generally opportunists. Grainger (1953) examined over 30 species in the stomachs of arctic char. Rikardsen et al. (2005) found that the marine diet of arctic char consisted mostly of a copepod species (Calanus finmarchicus) and krill (Thysanoëssa). Lake-dwelling arctic char fed mostly on insects and zoobenthos. Andrews and Lear (1956) found that some of primary food items of arctic char in Northern Labrador are capelin (Mallotus villosus), and mailed sculpin (Triglops murrayi). Arctic char are also known to eat insects, eggs, mollusks, zooplankton, amphipods and other aquatic crustaceans. Some giant arctic char have even been recorded as cannibals of their young as well as dwarf arctic char. (Andrews and Lear, 1956; Finstad, et al., 2006; Grainger, 1953; Rikardsen, et al., 2005)
Common predators of arctic char are sea otters (Enhydra lutris), polar bears (Ursus maritimus), humans (Homo sapiens), as well as other fish and larger arctic char. Arctic char are a main prey species of the apex predator, ferox trout (Salmo ferox), making arctic char key species of many of the lakes throughout their range. An anti-predator adaptation of arctic char is their ability to change coloration depending on environment. They generally have a darker color in lakes and a lighter color at sea. A study by Vilhunen and Hirvonen (2003) found that some juvenile arctic char had highly sensitive recognition of predator odors. Their results indicated that the innate anti-predator behavior of the juvenile fish is finely turned to respond specifically to chemical cues from different fish predators as well as the diets of predators. (Morrow and Dalen, 1980; Vilhunen and Hirvonen, 2003)
Arctic char are a main prey species of the apex predator, ferox trout (Salmo ferox). Known parasites of arctic char are protozoans, flukes, tapeworms, nematodes, thorny-headed worms, leeches, and crustaceans. The protozoan parasites of arctic char are Haemogregarina irkalupkiki, Henneguya zschokkei, and Myxidium oviforme. The flukes parasites of arctic char are Crepidostomum farionis, Crepidostomum metoecus, Lecithaster gibbosus, Tetraonchus alascensis, and Tetraonchus articus. Flatworm parasites of arctic char are Cyathocephalus truncatus, Diphyllobothrium norvegicum, Diphyllobothrium salvelini, Diplocotyle olrikii, Eubothrium crassum, and Eubothrium salvelini. The known nematode parasites of arctic char are Contracaecum aduncum, Metabronema salvelini, and Rhabdichona denudata. Known tapeworm parasites of arctic char are Pelichnibothrium speciosum, Proteocephalus exiguus, Raphidascaris acus, and Scolex pleuronectis. Thorny-headed worm parasites of arctic char are Metechinorhynchus salmonis, Metechinorhynchus truttae, Neoechinorhynchus rutili, and Pomphorhynchus laevis. Leech parasites of arctic char are Acanthobdella peledina. Crustacean parasites of arctic char are Salmincola edwardsi, Salmincola salmonea, Salmincola salvelini, and Salmincola thymalli. Another known parasite of arctic char is Phoma herbarum, which is a species of fungus that can sometimes be seen on the skin. (; Hammar, 2003; Hoffman, 1967)
Humans benefit from arctic char as a food source, as well as sport fishing and specimen collecting. Specimen collecting of arctic char benefits humans as a source for research and education. As food, arctic char are considered a highly priced delicacy. The market price of arctic char differs depending on volume. Higher prices correlate with lower volume. Prices in 2018 for arctic char average at around $9.90 per kg of dressed fish. Historically, prices for arctic char have been recorded as high as $24.18 per kg for fillets. (Freyhof and Kottelat, 2008)
There are no known negative impacts of arctic char on humans. (Freyhof and Kottelat, 2008)
Arctic char are listed on the IUCN Red List as a species of "Least Concern." The US Federal List, CITES appendices, and State of Michigan List have no special status listings for arctic char.
The biggest threat to arctic char is humans. Another threat to arctic char is stream acidification. In southern Scotland, several populations of arctic char have gone extinct due to acidification of the streams. Many arctic char populations in Ireland have gone extinct due to lake acidification and reduced water quality, caused by domestic and agricultural pollution. A suspected threat that some arctic char populations deal with is lack of genetic variation. The arctic char population in Lake Siamaa in southeast Finland relies on aquaculture in order to survive, which is believed to be because the lack of genetic variation in the native population causes egg and alevin mortality as well as disease susceptibility.
Management of stream acidification in southern Scotland is a possible conservation effort for arctic char. Conservation methods have been proposed in Ireland as an attempt to protect the populations of arctic char that remain. Some of the proposed methods include implementing sustainable development, transplanting juvenile stock, control of nutrient input, and preventing the introduction of predatory fish in lakes that contain arctic char. Resupplying the stocks of arctic char in lakes is another conservation effort that is made in some locations, such as Lake Siamaa in southeast Finland. (Freyhof and Kottelat, 2008; Maitland, et al., 1991; Primmer, et al., 1999)
Miranda Flack (author), Radford University, Layne DiBuono (editor), Radford University, Lindsey Lee (editor), Radford University, Kioshi Lettsome (editor), Radford University, Karen Powers (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
the body of water between Europe, Asia, and North America which occurs mostly north of the Arctic circle.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
areas with salty water, usually in coastal marshes and estuaries.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.
fertilization takes place outside the female's body
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
mainly lives in water that is not salty.
a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.
Found in northern North America and northern Europe or Asia.
Animals with indeterminate growth continue to grow throughout their lives.
An animal that eats mainly insects or spiders.
the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
makes seasonal movements between breeding and wintering grounds
eats mollusks, members of Phylum Mollusca
Having one mate at a time.
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
chemicals released into air or water that are detected by and responded to by other animals of the same species
an animal that mainly eats fish
an animal that mainly eats plankton
having more than one female as a mate at one time
"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.
mainly lives in oceans, seas, or other bodies of salt water.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)
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