Latin name

Prosopium cylindraceum

Other names

Menominee, round fish, frost fish, pilot fish, grayback; French: ménomini rond.

Identification

The Cod Whitefish is mostly silver with a dark brown to almost bronze coloration with a greenish tinge on the back. It has scales with black edges, especially on the back. The lower fins are amber in color, becoming more orange during spawning, and the adipose fin usually has brown spots. Juveniles have two or more rows of black spots on the sides, which may merge into a row of black spots on the back. The round whitefish has a small head, a fairly sharp snout, and a single flap of skin between the nostrils. It also has a forked caudal fin, 74 to 108 scales along the lateral line, and 14 to 21 gill slits. The round whitefish and the lake whitefish are easily distinguished because the round whitefish has a very cylindrical body, while the lake whitefish's body is compressed from the sides.

Distribution

The round whitefish is found in Arctic outflows and is a widespread species in northern North America. It has scattered populations, one of which inhabits the St. Lawrence and Great Lakes Basin (except Lake Erie) as far north as the Arctic Ocean east of Hudson Bay. Another population occurs in the northern provinces of Canada and Alaska west of Hudson Bay. It also occurs in limited areas immediately south of Hudson Bay and in East Twin Lake, Connecticut.

Habitat

They inhabit the shallow areas of lakes and streams, and may also inhabit rivers with fast currents and rocky bottoms. They rarely enter brackish water or water deeper than 150 feet.

Size

Typically 8 to 12 inches long and weighing 1⁄2 pound or less, round whitefish can grow to 20 inches long and weigh several pounds. The world record for all-tackle fishing is a 6-pounder caught in Manitoba in 1984.

Life history and Behavior

Spawning occurs in the fall in lakes, at the mouths of tributaries, and sometimes in rivers on gravel shoals. Fish spawn in pairs and spawn in early spring.

Food and feeding habits

Round whitefish feed on bottom invertebrates and sometimes fish and fish roe.

Reproduction

No information