Round Whitefish

Scientific Name: Prosopium cylindraceum

Common Names: Round Whitefish, Frostfish, Round Fish and Menominee Whitefish

Round Whitefish have long, cylindrical bodies with large scales. Toward their topside, these scales are a golden brown that fade to a white color that covers their bellies. They have small, laterally compressed mouths and snouts that are pointed slightly downward.

Round Whitefish are commonly confused with Lake Whitefish, with the main difference between the two being that Round Whitefish have a flap of skin between their nostrils while Lake Whitefish do not. This characteristic also helps to distinguish Round Whitefish from Cisco fish.

The average size of Round Whitefish ranges from 8 to 12 inches, but some have grown to sizes of 22 inches or longer. Though their growth comes more slowly when compared to that of Lake Whitefish, Round Whitefish commonly live up to 8 years of age.

Spawning in the fall around November and December, Round Whitefish lay their eggs over gravel areas. Recruitment of their young is sometimes hurt by low water levels that can leave their eggs frozen. Still, they are easy to find in all the Great Lakes with the exception of Lake Erie.

Round Whitefish Interesting Facts

Common predators of Round Whitefish are Smallmouth Bass and Yellow Perch;
Round Whitefish are rarely seen or caught by fishermen;
They have a tendency for solitude, resting in deep waters;
and Round Whitefish like to feed on clams, snails, insects and the eggs of other fish.

Round Whitefish Distribution

Round Whitefish are considerably abundant in Alaska, where they can be found throughout waters in the state. On the U.S. mainland, they can be found in Lake Superior, Lake Michigan-Huron and Lake Ontario. Round Whitefish populations are also numerous in the U.S. Northeast, living in states including Maine, New Hampshire and New York.

Distribution of Round Whitefish in the continental United States. (Credit: U.S. Geological Survey)

Round Whitefish Biology

A study published in the North American Journal of Fisheries Management in October 2013 found that the hatching window of Round Whitefish eggs is largely dependent on temperature. As temperatures increase, scientists noted that the hatching window goes up as well.

A multi-decade investigation published in a 2014 edition of Aquatic Ecosystem Health & Management used gill nets to track fish communities in northeastern Lake Ontario. From 1992 to 2012, scientists found that dominant fish species, including the Round Whitefish, showed peak abundance levels in the early 1990s.

An Alaskan study used radio transmitters to track the movements of different whitefish species in the Minto Flats-Chatanika River over the course of two years. Full results are published in Ecology of Freshwater Fish and indicate that spawning stocks in the river and streams nearby likely mix.

References Cited