''Oxygymnocypris stewartii'' is a species of

cyprinid Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest ver ...

fish

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

Tibet Tibet (; ''Böd''; ) is a region in East Asia, covering much of the Tibetan Plateau and spanning about . It is the traditional homeland of the Tibetan people. Also resident on the plateau are some other ethnic groups such as Monpa, Taman ...

and occurs in the

Yarlung Tsangpo River The Yarlung Tsangpo, also called Yarlung Zangbo () is the upper stream of the Brahmaputra River located in the Tibet Autonomous Region, China. It is the longest river of Tibet and the fifth longest in China. The upper section is also called D ...

(=upper

Brahmaputra The Brahmaputra is a trans-boundary river which flows through Tibet, northeast India, and Bangladesh. It is also known as the Yarlung Tsangpo in Tibetan, the Siang/Dihang River in Arunachali, Luit in Assamese, and Jamuna River in Bangla. I ...

) and its tributaries at altitudes above in the

Qinghai-Tibet Plateau The Tibetan Plateau (, also known as the Qinghai–Tibet Plateau or the Qing–Zang Plateau () or as the Himalayan Plateau in India, is a vast elevated plateau located at the intersection of Central, South and East Asia covering most of the Tib ...

. It is the only species in its genus.

Life history and ecology

''Oxygymnocypris stewartii'' grows to in standard length, in total length and in weight. It is a long-lived (to 25 years), late-maturing species that reproduces annually. ''Oxygymnocypris stewartii'' inhabits the deeper areas of clear, fast-flowing rivers with a rocky substrate. It is a generalized and opportunistic predator feeding both on fish and aquatic insects. Smaller specimens feed mostly on cobitid nemacheilid loaches and

caddisflies The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the ...

of family Hydropsychidae, whereas larger individuals switch more towards cyprinid fishes and

chironomid The Chironomidae (informally known as chironomids, nonbiting midges, or lake flies) comprise a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae. Many specie ...

larvae. '' Triplophysa stenura'' is the most prevalent prey species, present in 47% of stomachs, but '' Schizopygopsis younghusbandi'' contributes most (59%) to prey weight. Insects are more important in winter and spring, and fishes in summer and autumn.

Fishery

''Oxygymnocypris stewartii'' is heavily used as a food fish and is thought to be overfished.

References

{{Taxonbar, from=Q1104847 Cyprinid fish of Asia Freshwater fish of China Endemic fauna of Tibet Fish described in 1908