Nelma

Stenodus nelma, known alternatively as the nelma, sheefish, siifish, inconnu or connie, is a commercial species of freshwater whitefish in the family Salmonidae. It is widespread in the Arctic rivers from the Kola Peninsula (White Sea basin) eastward across Siberia to the Anadyr River and also in the North American basins of the Yukon River and Mackenzie River.

Appearance and lifestyle
Stenodus nelma is an anadromous fish, up to 150 cm in length. The fish has a large mouth with a protruding lower jaw and a high and pointed dorsal fin. It is generally silver in color with a green, blue or brown back. The meat is white, flaky and somewhat oily. An adult fish weighs up to 27 kg.

The fish eat plankton for their first year of life and then become predators of smaller fish. They live in lakes and rivers and in the brackish water at the outlets of rivers into the ocean. They may migrate more than 1600 km to their upriver spawning grounds, but some populations spend their entire life in fresh water and do not migrate.

Systematics
Stenodus nelma has previously been considered a subspecies of Stenodus leucichthys (S. leucichthys nelma). The typical Stenodus leucichthys (beloribitsa) is a landlocked Eurasian species restricted to the Caspian Sea basin, and now extinct in the wild.