Arctic charr Salvelinus alpinus; Linnaeus, 1758. Family: Salmonidae
The Arctic charr (Salvelinus alpinus) is a typical salmonid, with slender body and a small, rayless adipose fin situated between the rayed dorsal and tail fins. The appearance is highly variable; males often have distinctive red pectoral, pelvic and anal fins with white fore-edges while the dorsal fin is unspotted. It is native to the northern Hemisphere, in Europe, Asia and North America.
Like most other salmonids, Arctic charr spawn in autumn or in late winter and early spring, often in gravel areas along loch shores. While they also occasionally spawn in streams flowing into lochs, emerging fry migrate downstream and generally do not form stream populations. Isolation of populations for long periods of time and differences in diet have led to development of local variants and in some instances two or more forms have evolved within the same loch. Arctic charr are a major prey item in lochs with large fish-eating trout (ferox). Few wild Arctic charr reach more than 30 cm in length or 300 g in weight although in the presence of freshwater fish farms, where there is a surplus of fish pellets or escaped fish to exploit, they can reach weights in excess of 3 kg.
Diet and Behaviour
The diet of Arctic charr is similar to that of Brown trout, although where the two species occur together, Brown trout will tend to favour shallow water insect larvae and freshwater shrimp, while the Arctic charr will feed on zooplankton, small mussels and midge larvae.
Distribution in Scotland
The Arctic charr prefers cold northern conditions and its stronghold in Scotland is in the Highlands where over 200 populations exist.
They were probably among the first fish to re-enter fresh waters when the last ice age ended. Arctic charr in Scotland have been largely unexploited and until very recently unadulterated, making the Scottish populations unique in Europe. However, in the UK's Biodiversity Action Plan the species is now considered as 'threatened or declining in range' due to such factors as global warming, land use changes and species introductions.
Charr as a Sport Fish
Arctic charr are a major food and recreational resource in many northern countries, especially for remote communities in Arctic and moutain regions. No comparable recreational or commercial fisheries for Arctic charr have developed in Scotland.