Longnose Sucker, Catostomus catostomus

Longnose sucker, Catostomus catostomus.

This species has an elongate, torpedo-shaped body that is almost round in cross-section. Its head is moderately long, broad, and rounded on top, while its long snout ends in a rounded point. Its mouth is ventral, positioned well behind the tip of the snout, and its lips are large. Adults are dark olive or grey, with brassy reflections on the back, upper sides, and the top of the head. The sides and ventral surface of the head and body are cream to white in colour. During breeding, both males and females have a broad horizontal band of vivid red running along their sides, which continues to the snout, although the colour is more intense on the males. The upper surface of breeding males is almost black, compared to the green-gold or copper colour of females. During the mating season, the undersurface of the head is yellow to orange, while the ventral surface of the body is white to pink.

The longnose sucker has a broad distribution occurring throughout Canada, except in Newfoundland. Its northern Canadian range extends to the limit of the continental Northwest Territories and the northern tip of Labrador. This is the only North American sucker that also occurs in Asia. It prefers to live in moderately large schools and in clear cold water where food is variable, depending on the location and season. Plants and invertebrates, such as aquatic insect larvae, crustaceans, and snails, are taken from the bottom. Longnose suckers are eaten by bears, eagles, and predatory fish like the northern pike.

Longnose suckers spawn in streams or shallow areas of lakes from mid-April to mid-May. Spawning occurs during daylight, when the female moves from the quiet waters near shore into a group of males near the stream centre. Two to four males crowd around each female, clasping her or beating against her with their anal fins. This spawning act lasts for 3 to 5 seconds and occurs as often as 6 to 40 times per hour! No nest is built; instead the eggs are deposited in the gravel of the stream bottom and the suckers return to their previous positions in the stream. Sexual maturity is thought to occur at 5 to 7 years of age, and their lifespan is estimated to be 19 years.