Arctic cisco (Coregonus autumnalis), also known as omul Russian: Омуль, is an anadromous species of freshwater whitefish that inhabits the Arctic parts of Siberia, Alaska and Canada. It has a close freshwater relative in several lakes of Ireland, known as the pollan, alternatively regarded as conspecific with it, or as a distinct species. The freshwater omul of Lake Baikal, formerly considered a subspecies Coregonus autumnalis migratorius of the Arctic cisco, has no close genetic relationship to it and is now classified as a separate species, Coregonus migratorius. The Arctic cisco have a relatively small head with a non-prominent snout. They have metallic silver body, a brown or dark green back, and nearly colorless fins. They have neither spots nor teeth on their jaws. They do have a patch of teeth on their tongue. They can reach 50 cm (20 in) in length and can weight up to 2 kg (4.4 lbs), but are usually less than 40 cm (16 in) in length and 1 kg (2.2 lbs) in weight. Arctic cisco can be found in the Beaufort Sea, Colville River delta, and freshwater drainages east of the Sagavanirktok River. They can be found in several drainages in the Northwest Territories and Siberia, such as the Chaun River, and are not often found east of Point Barrow.
