Fisheries and Land Resources

White Sucker

Catastomus commersoni


Restricted to North America, and widely distributed throughout Canada. In our province, the species occurs only in Labrador.


Wide range of habitats from rocky pools and riffles of headwaters to larger lakes, usually in small, clear, cool creeks and small- to medium-sized rivers.


White Suckers feed at night. Adult diet consists of insect larvae, mollusks, and other invertebrates.


Olive-brown to black above, often dusky-edged scales with clear to dusky fins.

Breeding Biology

White Suckers primarily spawn in the spring, usually early May to early June. Adults migrate from lakes into gravelly streams, when stream temperatures reach 10oC. Spawning sites are in shallow waters with a gravel bottom Adults will return to specific spawning site; thousands may migrate to the site at a particular period.

Spawning usually occurs at dusk and in the late evenings. Two to four males will crowd around a ripe female, and using their fins, will press against it. A spawning event will take about three to four seconds, with the female repeating the act six to 40 times in an hour. Females may carry 36,000 to 50,000 eggs. Suckers don't build nests or give parental care. Adults leave the spawning ground after 10 to 14 days, and eggs hatch in about two weeks. Young remain in the gravel for one to two weeks, and migrate back to the lake a month after spawning.


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