Round Whitefish (Prosopium cylindraceum)


A member of the Salmonidae family, the round whitefish seldom exceeds 2 pounds and is sought to a limited degree by anglers.

Identification

The round whitefish is mostly silvery and has a dark brown to almost bronze coloring, with a greenish tint on the back. It has black-edged scales, particularly on the back. The lower fins are an amber color, becoming slightly more orange during spawning, and the adipose fin is usually brown spotted. Young fish have two or more rows of black spots on the sides that may merge with a row of black spots on the back.

The round whitefish has a small head, a fairly pointed snout, and a single flap of skin between its nostrils. It also has a forked caudal fin, 74 to 108 scales down the lateral line, and 14 to 21 gill rakers. The round and the lake whitefish can be easily distinguished from each other because the round whitefish has a very cylindrical body, whereas the body of the lake whitefish is laterally compressed.

Size

Usually about 8 to 12 inches long and weighing 1⁄2 pound or less, the round whitefish can grow to more than 20 inches long and weigh several pounds. The all-tackle world record is a 6-pounder taken in Manitoba in 1984.

Spawning behavior

Spawning takes place during the fall in lakes, in tributary mouths, and occasionally in rivers over gravelly shallow areas. Fish spawn in pairs; their eggs hatch in the early spring.

Food

Round whitefish feed on benthic invertebrates and occasionally on fish and fish eggs.

Other Names

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

Distribution

The round whitefish occurs in arctic drainages and is a wide-ranging species in the northern portions of North America. It has disjunct populations, one of which is found through the St. Lawrence-Great Lakes basin (with the exception of Lake Erie), north to the Arctic Ocean east of Hudson Bay.

The other is found throughout the northern Canadian provinces and Alaska west of Hudson Bay. It also occurs in limited areas directly south of Hudson Bay and in East Twin Lake in Connecticut.

Habitat

Occurring in the shallow areas of lakes and streams, round whitefish may also inhabit rivers with swift currents and stony bottoms. They rarely enter brackish water or water more than 150 feet deep.

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