Arctic Cisco, Coregonus autumnalis

Arctic cisco, Coregonus autumnalis.

The arctic cisco is a silver-coloured fish with large scales, fleshy dorsal and adipose fins, no teeth, and a small appendage at the base of its pelvic fin (a pelvic axillary process). Its body is elongate and reaches a maximum length of 38 cm. Its dorsal fin is located approximately halfway down the back of the fish and its caudal fin is deeply lobed with both the upper and lower lobes being the same size. Its anal fin is positioned just ahead of the caudal fin on the underside of the body, while its small pectoral fins are positioned just behind and below the gill opening. The arctic cisco is largely silver with a brown or green sheen on its back; its fins have little pigmentation.

A mature arctic cisco, Coregonus autumnalis, captured at Wood Bay, near the Anderson River estuary, NWT. Photo: Jim Johnson.

The arctic cisco occurs in the coastal waters and lower parts of Arctic rivers in Europe, Asia, and North America. In Canada, its distribution is confined to the northern parts of the mainland Northwest Territories.

This fish has not been well studied in North America, but because it is harvested for food in Siberia, much research on its ecology and life history has been conducted in Russia. Adult arctic cisco feed on crustaceans and small fish. It is anadromous and adults spawn in freshwater streams and rivers, returning to the sea once mating is complete. Upstream migration occurs in July and spawning takes place over gravel beds in swiftly flowing water. The eggs, which can number over 40,000, are abandoned once they are expelled. When the eggs hatch in the spring, the young descend to the estuaries. Maturity is reached in 5–7 years.