The Peace/Williston Fish and Wildlife Compensation Program (PWFWCP)

View Larger Photo

Longnose Sucker
Catostomus catostomus

What do they look like?

A fine-scaled sucker with 9 to 11 dorsal rays and a large, rounded anal fin. In profile, the body tapers gradually back from the dorsal fin to a relatively deep caudal peduncle (its depth is well over half the width of the dorsal fin base). The snout is long and, when viewed from below, projects beyond the upper lip. The lower lips are large and, in profile, their hind margins extend back to about the middle of the nostril. Spawning males have a distinct red or pink lateral band set between a yellow-gold band above and a black band below.

Where do they live?

Throughout their extensive geographic range longnose suckers occur in both lakes and rivers. Their local distribution appears to be influenced by temperature. Although lake-dwelling adults seasonally forage inshore, they usually remain below the thermocline during the summer. However, at night some Williston region populations (e.g., Dina Lake #1), adults were commonly collected in the littoral zone. Little is known about the habitat use of adult longnose suckers in rivers; however, in the Parsnip River and its tributaries there is evidence of complex migrations to spring spawning sites, summer foraging sites, and over-wintering areas.

In both lakes and rivers, juvenile longnose suckers occupy habitats similar to those used by adults; however, juveniles typically occur in shallower and quieter water than adults. In streams they are often associated with beaver ponds or, in large rivers, with side-channels and embayments. In lakes, early in the summer, juveniles are found closer to shore than adults. In Dina Lake #1 trap nets set in <3.0 m caught large numbers of juvenile and young-of-the-year longnose suckers. As the lake warmed, juveniles became less abundant in daytime catches but remained abundant in overnight sets.

In rivers, newly emerged fry aggregate in quiet water that is often less than 10 cm deep. They are associated with soft substrates and during freshet they commonly aggregate in seasonally flooded vegetation. As they grow, young-of-the-year move into deeper water but still remain in quiet water areas (e.g., side-channels and backwaters behind deposition bars). In lakes, newly emerged fry stay inshore and remain close to cover (usually vegetation or woody debris). As the summer proceeds the young grow and by fall the largest individuals become solitary and move into deeper water.

What is their life like?

In British Columbia, there is only one published study of longnose sucker life history, but other reports are available. Lake-dwelling longnose suckers typically migrate into spawning streams to spawn. Their spawning migrations usually occur in the early spring and temperature (5°C) and flow are important factors in initiating spawning migrations. Most lacustrine populations show a preference for spawning in inlet streams. However, some populations spawn in lakes: the Dina Lake #1 longnose suckers spawn along the lake shore in shallow (<20 cm) water where wave action has eroded coarse gravel from undercut banks.

Longnose suckers typically spawn during the day. Although there is no site preparation, the substrate is often cleaned by the thrashing fish. The eggs are adhesive. Some eggs stick to the gravel surface and others fall into crevices among the rocks. Egg number varies with female size; large females (about 500 mm long) produce over 44,000 eggs. Development rate is temperature dependent and hatching occurs in about 11 days at 10 °C and at about a week at 16 °C. The newly hatched larvae are about 10 mm long and remain in the gravel until they are about 12 mm in total length. Feeding begins at about 14 mm and the mouth becomes subterminal at approximately 16 mm.

In the Williston region the young-of-the-year are approximately 40 mm long by the end of their first growing season. In Northern B.C. males mature at about 7 and females at about 9 years. Relatively few longnose suckers in B.C. exceed 500 mm in fork length and the oldest recorded age in B.C. is 19 years.

What do they eat?

As adults, longnose sucker are benthivores, but like many fishes they begin life foraging in shallow water on a variety of prey. Early in life the mouth is terminal but slowly shifts to a ventral position and is clearly subterminal by about 18 to 20 mm. In lacustrine populations, when the mouth is terminal, planktonic prey species (e.g., Daphnia, Cyclops, and Bosmina) are common in stomachs; in fluvial populations chironomid larvae are the most common prey. As the mouth changes position, the fish become more substrate-oriented and their diet shifts towards benthic prey, especially chironomid larvae and ostracods.

What is their distribution? The longnose sucker is the only sucker found in both North America and Asia. In North America, it is widespread in cool waters from Labrador to the Pacific Coast, and from the Arctic Coast south to Colorado in the west and Maryland in the east. In contrast, the Asian distribution is restricted to a few Arctic coastal drainages in eastern Siberia. In B.C., the longnose sucker occurs in all major drainage systems. It is an Interior species, however, and only approaches the coast in rivers that rise on the Interior Plateau and flow west through the Coast Mountains to the sea.

View Peace Williston distribution map.