Tahoe sucker

Tahoe sucker
Conservation status
Least Concern  (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Catostomidae
Genus:	Catostomus
Species:	C. tahoensis
Binomial name
Catostomus tahoensis T. N. Gill & D. S. Jordan, 1878
Known watershed locations of Catostomus tahoensis
Synonyms
Catostomus arenarius Snyder, 1917 Chasmistes chamberlaini Rutter, 1903

The Tahoe sucker (Catostomus tahoensis) is a freshwater cypriniform fish inhabiting the Great Basin region of the Western United States.

Description

The Tahoe sucker is a large, long fish with a tapering head. It can grow up to 24 inches (610 mm) in larger lakes, but rarely exceeds 6 inches (152.4 mm) in streams. Its rather large suckermouth is located on the bottom of the head, commonly referred to as a subterminal mouth. Where its lower lips are thick and fleshy, its upper lips contain 2-4 rows of papillae. The caudal fin is moderately forked. There are 83 to 87 scales in the lateral line. They are very dark above, lighter below, with dusky fins. Breeding males display a bright red lateral line and breeding tubercles on the anal fin and tail.

Distribution and habitat

These fish are native to the Lahontan Basin of southeastern Oregon, Nevada, and northeastern California, of which it is one of the most common fishes. It has also been introduced into the upper Sacramento River system. The total adult population is believed to number over 100,000, and it is considered to be common or abundant in its various habitats.

Tahoe suckers are mainly found in large lakes and reservoirs, but can also be found in ponds in lower reaches of streams. They predominantly live in cool streams, but are capable of withstanding temperatures exceeding 25°C. Adults occupy moderate to deeper depths. Young are found in shallow waters or tributary streams, where water travels slower.

Occupied watersheds

• East Branch North Fork Feather Watershed
• East Walker Watershed
• Honey-Eagle Lakes Watershed
• Lake Tahoe Watershed
• Middle Fork Feather Watershed
• North Fork American Watershed
• North Fork Feather Watershed
• Truckee Watershed
• Upper Carson Watershed
• West Walker Watershed

Diet habits

Tahoe Suckers are omnivorous. They use their sub-terminal mouths to probe the bottom of streams or lakes for insect larva, worms, micro-crustaceans living under rocks, or algae. Adults tend to feed at night. The young feed on cladocerans and other microorganisms found within or near algae and aquatic vegetation.

In lakes, they are capable of growing to much greater sizes by foraging deep below the surface, sometimes as deep as 300 m. Unlike stream dwelling Tahoe suckers, their diet consists of larger organisms, comprising midge larvae, annelid worms, amphipods, algae, and crustaceans.

Their diet contributes to their importance in maintaining the health and efficiency of freshwater landscapes in the west. By steadily feeding on the bottom, Tahoe suckers keep organic clutter from building up.

Reproduction

Tahoe suckers reach sexual maturity between 2 and 5 years of age, with males tending to mature earlier. Differences in age at which maturity is reached exist between various populations. Those in Pyramid Lake mature several years earlier than those in Lake Tahoe. Fecundity is believed to be related to size, with age being of secondary influence. Nuptial tubercles begin to appear on both sexes prior to the onset of the mating season, although they are rare on females. On males they form distinct rows on the anal and caudal fins.

In lakes, the Tahoe sucker prefers to spawn over rock and gravel substrates when water temperatures are 12-23°C. Stream dwelling suckers move upstream to riffles at night when water temperatures are 11-14°C. After scattering her eggs into the gravel bed, the female shakes them down into the substrate. Simultaneously, the attendant males release their sperm in order to fertilize the released eggs.

Assuming the average body length is 31 cm FL, an average of lake suckers is 20,555 eggs. Fewer eggs are produced in female stream dwelling suckers. Sustained seasons of  increased water level can lead to a higher yield in eggs, as the high water helps maintain a protective environment for larval and post-larval suckers.

Importance to humans

Historically, the Tahoe sucker was largely ignored by the indigenous Paiute peoples, who preferred Cutthroat trout and Cui-ui sucker. Despite the fish's size and good taste, it continues to have no economic significance.

Due to being bottom feeders, lake dwelling Tahoe suckers are hard to access. Additionally, those living in streams tend to be significantly smaller and less substantive for food than lake dwelling suckers. There are no fisheries tailored to them.

References

• Froese, Rainer; Pauly, Daniel (eds.). "Catostomus tahoensis". FishBase. January 2016 version.
• "Catostomus tahoensis". Integrated Taxonomic Information System. Retrieved 23 January 2016.