An inconnu is a silver-scaled whitefish that inhabits Arctic and sub-Arctic waters. Found primarily in the Yukon, British Columbia, and Siberia, the inconnu is also known as the sheefish or coney. This species, Stenodus leucichthys, is the largest within the whitefish family, growing as long as 4.9 feet (1.5 m) in certain areas. Although the inconnu has been a staple in indigenous peoples’ diets for thousands of years, it is not typically harvested or farmed for commercial purposes.
This fish typically has silvery scales with green or brown markings on its back. The average adult length is between 17 and 30 inches (45 to 75 cm), though some captured in Siberian waters have been reported close to 5 feet in length (1.5 m). Their average adult weight is 40 pounds (18 kg). These fish have a jutting lower jaw studded with many extremely-fine teeth and a dorsal fin low on the spine closer to their forked tail than in other whitefish.
Little is known about the inconnu’s life cycle. It is believed to spawn every two to four years, either migrating from the ocean to freshwater rivers or remaining in freshwater lakes year-round, depending on the species. Young inconnu inhabit their spawning streams for seven to 10 years when they become mature adults, then move to larger lakes. The North American version of this fish is estimated to live for 11 years, while its Siberian cousin has been reported to live twice as long.
Adult inconnu are carnivorous, eating smaller fish such as stickleback and minnows, small crustaceans, and aquatic insects. Their young eat primarily zooplankton and water insect larvae, only progressing to larger prey once they are adults and have moved into their lake habitats. Once inconnu are grown, they have few, if any, predators. Juveniles, however, are often eaten by larger fish, including their own species.
One species of this silvery whitefish has disappeared from the wild. The population used to migrate almost 2,000 miles (3,218 km) from the ocean to lake spawning grounds each year, but once their migration waterways were interrupted by dams, this species failed to thrive. They now exist only in fish hatcheries, though attempts are being made to restock their former habitats.
Though the inconnu has been eaten by native peoples throughout history, it is not a typical food fish for most of North America.