Fisheries and Land Resources

Slimy Sculpin

Cottus cognatus


This species extends through northern North America and to extreme northeastern Siberia. In this province it occurs in Labrador.


Habitat requirements appear to vary greatly depending on available substrate and temperature, but generally inhabits deeper waters (has been found in 354ft of water) of lakes and cooler streams, darting swiftly from place to place when disturbed.


A benthic (bottom) feeder, with aquatic insect larvae and nymphs making up most of its diet.


Dark brown, green, or gray above, with dark gray mottling on back and upper sides; prickles often on head and behind pectoral (side) fins.

Breeding Biology

Spawning habits are not known well in Canada, and few studies have been published. The species has been captured in stony shallows when spawning, and some individuals were 2.5 inches long and full of eggs in May. Spawning begins when water temperatures are at 5oC in lakes and 10oC in streams.

Males select a spawning site under a ledge or rock. The female is courted and enters the nest when she accepts the male as a spawning partner. The female lays its eggs as an adhesive mass on the ceiling of the rock or ledge of the spawning site. The female either leaves or is driven out by the male, which then guards and aerates the eggs by fanning with his pectoral fins. Four-inch females are capable of producing 1,400 eggs, which hatch in approximately 14 days. These fish grow up to about 4.5 inches long.


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