Sucker, Shortnose

views updated

Sucker, shortnose

Chasmistes brevirostris

phylum: Chordata

class: Osteichthyes

order: Cypriniformes

family: Catostomidae

status: Endangered, IUCN Endangered, ESA

range: USA (California and Oregon)

Description and biology

Suckers are large fish that feed by siphoning food with their mouths from the bottom of their freshwater habitat. The short-nose sucker differs from other suckers in that its mouth does not run straight across the end of its head but is tilted at an angle. It feeds on zooplankton (microscopic aquatic animals), algae, and aquatic insects. This sucker can grow to a length of 25 inches (63.5 centimeters) and live as long as 33 years.

Female shortnose suckers spawn (lay eggs) in the spring in rivers, streams, or springs connected to their lake habitat. A single female can lay up to 46,000 eggs during the spawning season.

Habitat and current distribution

Shortnose suckers prefer to inhabit freshwater lakes or reservoirs. They migrate up fast-moving connected waterways

to spawn. They are currently found primarily in Upper Klamath Lake and its tributaries in south-central Oregon. Smaller populations are located in the Clear Lake and Iron Gate Reservoirs in north-central California. In the mid-1980s, biologists (people who study living organisms) estimated that 2,650 shortnose suckers left Upper Klamath Lake to spawn. That number has decreased greatly in recent years.

History and conservation measures

The shortnose sucker was once common throughout the Upper Klamath River Basin (region drained by the river and the streams that flow into it). This basin once encompassed a drainage area of approximately 5,301,000 acres (2,120,400 hectares). The basin also contained over 350,000 acres (140,000 hectares) of wetlands and floodplains.

Over the years, this area has been drastically altered. Dams were built on rivers to supply water to communities and farms. Irrigation canals were also constructed to divert water to farms. Wetlands, marshes, and floodplains were drained to create land for houses and farms. In the basin, only 75,000 acres (30,000 hectares) of wetlands remain. These changes have not only destroyed much of the shortnose suckers' habitat, but broken up any remaining habitat into sections.

The draining of wetlands has reduced the quality of water feeding the suckers' habitat. As water flows through wetlands into rivers and lakes, the wetlands act as a filter by capturing and neutralizing surface pollutants. Without them, the pollutants flow right through, eventually building to a point where they poison freshwater systems.

Dams have created reservoir habitats where the suckers can live, but they have also prevented the fishes from reaching their spawning grounds. Biologists estimate that dams and other alterations to the shortnose suckers' habitat have reduced the fishes' ability to reproduce by as much as 95 percent. Unless spawning areas are reestablished for the shortnose sucker, its survival is considered unlikely.