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sawfin
The sawfin (''Barbus serra''), also known as Clanwilliam sawfin, is a ray-finned fish species in the family Cyprinidae. It is placed in the "wastebin genus" ''Barbus'' – the typical barbels and relatives – by default. But actually it is far less closely related to the typical barbels than to the South African redfins in ''Pseudobarbus'', and may well belong in the latter genus. Like ''Pseudobarbus'' but unlike most other African "barbs", it is tetraploid. Its closest living relative is probably the Cape whitefish (''B. andrewi'').〔de Graaf ''et al.'' (2007)〕
This sizeable cyprinid can grow to over long and weigh more than .〔Impson & Swartz (2007)〕
==Distribution and ecology==
It is endemic to the Western Cape Province of South Africa, where it was formerly widespread in the Olifants River and its tributaries. Its range has decreased throughout most of the 20th century, and by now it is apparently only found in the upper Olifants River as well as the Biedou, Doring, Driehoeks, Jan Dissels, Oorlogskloof, Ratels and Tra Tra Rivers.〔
It is rather euryoecious, inhabiting a wide variety of small and large rivers. While young fish are common in pools in the foothills, adults will move further down to where the rivers enter the coastal plain and the water is deeper. The sawfin is omnivorous, but mainly eats aquatic insects and their larvae. Its breeding season runs from late spring to summer (October to December), when schools of adults form to migrate upriver to shallow riffles with cobble ground, where they spawn. This species is long-lived and slow-growing, with yearlings being about long. It is only half-grown at about 4 years of age, and can get more than 10 years old.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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