Slimy Sculpin
Cottus cognatus
Status
The range of this species extends through northern North America. To
extreme northeastern Siberia. In our province it occurs in Labrador.
Habitat
Habitat requirements appear to vary greatly,
depending on available substrate and temperature. In general it inhabits the
deeper waters (has been found in 354ft of water) of lakes and cooler streams,
darting swiftly from place to place when disturbed.
Food
The animal is a benthic (bottom) feeder with
aquatic insect larva and nymphs making up the bulk of its diet.
Appearance
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
The spawning habits of this animal are not known well in Canada and
few studies have been published. The animal has been captured in stony shallows
when spawning. They have captured some individuals that were 2.5 inches long and
full of eggs in May. Spawning begins when water temperatures are at 50C
in lakes and 100C in streams. The male selects 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. Eggs are layed 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. The male then guards and aerates the eggs by fanning with his
pectoral fins. It is known that females at 4 inches in length are capable of
producing 1400 eggs and that eggs hatch in approximately 14 days. They grow up
to about 4.5 inches in length.
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