White Sucker - Catostomus commersoni

Habitat requirements and life history: The white sucker is a native, loosely schooling fish. It is currently the most abundant fish in the Assabet River. It can inhabit a wide range of habitats including streams, rivers and lakes where the water is brown or tea-colored (from tannin), the bottom is often gravel or rock, and the current is pronounced. Aquatic vegetation is usually sparse or absent. White suckers are bottom feeders with a mouth that faces downward and resembles a snout. The fish uses its mouth to attach to rocks and vacuum the bottom for aquatic insect larvae, crustaceans, snails, fish eggs and detritus. They move upstream into the tributaries in May and June to spawn in the riffles. Here they usually clear the bottom of the spawning area of silt and debris. The expulsion of eggs and milt (fish sperm) by the fish is violent enough to raise clouds of silt, sand and gravel that help cover the eggs. The eggs hatch in about 10-11 days. (Sources: Freshwater Fishes of the Carolinas, Virginia, Maryland, & Delaware and AMC Guide to Freshwater Fishing in New England)

Photo credit: Bill Byrne, MA Division of Fisheries and Wildlife

Total length: about 24 inches (occasionally 28-30 inches)
Pollution tolerance (US EPA): Tolerant
Classification: Fluvial dependent

Number of fish found during 1954 and 2001 Fish Surveys.*

*Data sources:
DFW. 2001. Assabet Watershed Fish Survey. Mass. Division of Fisheries and Wildlife (MassWildlife), Westborough, MA.

Schlotterbeck, L.C. and W.A. Tompkins. 1954. "A Fisheries Investigation of the Merrimack and Ipswich River Drainages." Bureau of Wildlife Research and Management, Mass. Division of Fisheries and Wildlife, Westborough, MA.