Arctic charr
The Arctic char or Arctic charr (Salvelinus alpinus) is a cold-water fish in the family Salmonidae, native to alpine lakes, as well as Arctic and subarctic coastal waters in the Holarctic.
The Arctic char was initially scientifically described in the salmon genus Salmo as Salmo alpinus by Carl Linnaeus in the 1758 edition of Systema Naturae, which is the work that established the system of binomial nomenclature for animals. Meanwhile, he described Salmo salvelinus and Salmo umbla, which were later considered as synonyms of S. alpinus. John Richardson (1836) separated them into a subgenus Salmo (Salvelinus), which now is treated as a full genus. The genus name Salvelinus is from German Saibling – little salmon.
The English name is thought to derive from Old Irish ceara/cera meaning " red", referring to its pink-red underside. This would also connect with its Welsh name torgoch, "red belly".
In North America, three subspecies of Salvelinus alpinus have been recognized. "S. a. erythrinus" is native to almost all of Canada's northern coast. This subspecies is nearly always anadromous. S. a. oquassa, known as the blueback trout or Sunapee trout, is native to eastern Quebec and northern New England, although it has been extirpated from most of its northeastern United States range. S. a. oquassa is never anadromous. Dwarf Arctic char has been classified as S. a. taranetzi. These scientific names are not generally accepted, however, as the names S. a. erythrinus and S. a. taranetzi usually refer to subspecies that are endemic to Siberia only.
Arctic char is also found in Lake Pingualuit in the Ungava Peninsula, Quebec, a lake situated in an impact crater formed roughly 1.4 million years ago. Since the last glaciation, changing water levels are believed to have connected the lake with glacial runoff and surrounding streams and rivers, allowing char to swim upstream into the lake. Arctic char is the only fish found in the lake, and signs of fish cannibalism have been found.
The Arctic char is closely related to both salmon and lake trout, and has many characteristics of both. The fish is highly variable in colour, depending on the time of year and the environmental conditions of the lake where it lives. The appearance of Arctic char differs between populations. The dorsal side of the Arctic char is dark in its colour while the ventral varies from red, yellow, and white.
Arctic char has a distinct size dimorphism, dwarf and giant. Dwarf Arctic char weigh between 0.2 and 2.3 kg (7 oz and 5 lb 1 oz) and average a length of 8 cm (3 in), while giant Arctic char weigh between 2.3 and 4.5 kg (5 lb 1 oz and 9 lb 15 oz) and average 40 cm (16 in) in length. Individual fish can weigh 9 kg (20 lb) or more with record-sized fish having been taken by anglers in Northern Canada, where it is known as iqaluk or tariungmiutaq in Inuktitut. Generally, whole market-sized fish are between 1 and 2.5 kg (2 lb 3 oz and 5 lb 8 oz). Male and female Arctic char are the same size.
The flesh colour can range from a bright red to a pale pink.
It spawns in freshwater and its populations can be lacustrine, riverine, or anadromous, where they return from the ocean to their fresh water birth rivers to spawn. No other freshwater fish is found as far north; it is, for instance, the only fish species in Lake Hazen which extend up to 81°56′N 68°55′W / 81.933°N 68.917°W / 81.933; -68.917 (Lake Hazen (northeast)) on Ellesmere Island in the Canadian Arctic. It is one of the rarest fish species in Great Britain and Ireland, found mainly in deep, cold, glacial lakes, and is at risk there from acidification. In other parts of its range, such as the Nordic countries, it is much more common, and is fished extensively. In Siberia, it is known as golets (Russian: голец) and it has been introduced in lakes where it sometimes threatens less hardy endemic species, such as the small-mouth char and the long-finned char in Elgygytgyn Lake.
Arctic char can be anadromous, landlocked, or semi-anadromous.
Arctic chars found north of 65°N latitude are generally anadromous. Anadromous Arctic chars spend their juvenile years in fresh water, and once mature, migrate annually to the marine environment. The first migration of Arctic char has been found to occur between 4 and 13 years of age. When in the marine environment, Arctic chars inhabit coastal and intertidal areas. They migrate back to frozen lakes at the end of summer.
Generally, Arctic char inhabits shallow waters, rarely swimming deeper than 3 m (10 ft) depth. An exception to this applies to landlocked Arctic chars, which often swim much deeper in the summer in order to occupy colder waters. Dwarf Arctic chars are more common in landlocked populations as a result of scarce resources (immense competition).
Arctic char exhibits a mostly circumpolar distribution. There is no other species of freshwater fish found at a higher latitude. Arctic char is native to Arctic and subarctic coasts and lakes of high elevations. In general, it has been observed in the Canadian Arctic, Greenland, Iceland, Scandinavia, Siberia, and Alaska.
Anadromous Arctic chars migrate to the sea annually in mid-June to mid-July. After about two months, they return to fresh water to reproduce and overwinter.
The diet of Arctic char varies with season and location. Arctic chars are generally opportunists. There have been more than 30 species found in the stomachs of Arctic chars.
During late spring and summer, Arctic char feeds on insects found on the water's surface, salmon eggs, snails and other smaller crustaceans found on the lake bottom, and smaller fish up to a third of its size. During the autumn and winter months, it feeds on zooplankton and freshwater shrimps that are suspended in the lake, and also occasionally on smaller fish.
The marine diet of Arctic char consists mostly of a copepod species (Calanis finmarchicus) and krill (Thysanoëssa). Lake-dwelling Arctic chars feed mostly on insects and zoobenthos. Some giant Arctic chars have been recorded as cannibals of their young as well as dwarf Arctic chars.
