The sawfin (''Pseudobarbus serra''), also known as Clanwilliam sawfin, is a

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Cyprinidae. It is placed with the

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

n redfins in ''

Pseudobarbus ''Pseudobarbus'' is a ray-finned fish genus in the family Cyprinidae. The type species is Burchell's redfin (''P. burchelli''). The scientific name is derived from the Ancient Greek ''pseudes'' ("false") and the Latin word ''barbus'' ("beard", ...

''. It is

tetraploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains ...

. Its closest living relative is probably the Cape whitefish (''P. capensis'').de Graaf ''et al.'' (2007) This sizeable

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 ...

can grow to over long and weigh more than .

Distribution and ecology

It is

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 ...

to the

Western Cape Province The Western Cape is a province of South Africa, situated on the south-western coast of the country. It is the fourth largest of the nine provinces with an area of , and the third most populous, with an estimated 7 million inhabitants in 2020 ...

, where it was formerly widespread in the Olifants River and its

tributaries A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainag ...

. 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 A coastal plain is flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and a piedmont area. Some of the largest coastal plains are in Alaska and the southeastern United States. The Gulf Co ...

and the water is deeper. The sawfin is

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

, but mainly eats aquatic

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

s and their

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e. Its breeding season runs from late spring to summer (October to December), when

school A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes comp ...

s of adults form to migrate upriver to shallow

riffle A riffle is a shallow landform in a flowing channel. Colloquially, it is a shallow place in a river where water flows quickly past rocks. However, in geology a riffle has specific characteristics. Topographic, sedimentary and hydraulic indica ...

s with

cobble Cobble may refer to: * Cobble (geology), a designation of particle size for sediment or clastic rock * Cobblestone, partially rounded rocks used for road paving * Hammerstone, a prehistoric stone tool * Tyringham Cobble, a nature reserve in Tyr ...

ground, where they

spawn Spawn or spawning may refer to: * Spawn (biology), the eggs and sperm of aquatic animals Arts, entertainment, and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** '' Spawn: ...

. This

is long-lived and slow-growing, with

yearling Yearling may refer to: *Yearling (horse), a horse between one and two years old *''The Yearling ''The Yearling'' is a novel by American writer Marjorie Kinnan Rawlings, published in March 1938. It was the main selection of the Book of the Mo ...

s being about long. It is only half-grown at about 4 years of age, and can get more than 10 years old.

Status and conservation

This species is considered

Near Threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify f ...

by the IUCN, as it has declined much between the 1930s and 1970s. This seems to have been mainly due to the introduced smallmouth bass (''Micropterus dolomieu''), which can kill off antire

subpopulation In statistics, a population is a Set (mathematics), set of similar items or events which is of interest for some question or experiment. A statistical population can be a group of existing objects (e.g. the set of all stars within the Milky Way g ...

s by eating the juveniles.

Clanwilliam yellowfish The Clanwilliam yellowfish (''Labeobarbus seeberi'') is a ray-finned fish species in the family Cyprinidae. It has long been placed in ''Barbus'', the "wastebin genus" for barbs, by default; however, the species is increasingly being restored to ...

(''Labeobarbus capensis'') might be regarded as a competitor for food, but this is apparently not significant. Other threats are

water pollution Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. ...

and overuse, mainly due to

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people t ...

. Overall however, its stocks are healthy wherever the smallmouth bass is absent, but this still restricts its range quite a lot. It is also listed as Endangered by the Nature Conservation Ordinance of

. For the time being, it may not be killed or caught. Considerable populations are found in the

Cederberg Wilderness Area The Cederberg mountains are located near Clanwilliam, approximately 300 km north of Cape Town, South Africa at about . The mountain range is named after the endangered Clanwilliam cedar (''Widdringtonia wallichii''), which is a tree end ...

, Matjies River Nature Reserve and Oorlogskloof Nature Reserve. In 2004, the Greater Cederberg Biodiversity Corridor was established by

CapeNature CapeNature (officially the Western Cape Nature Conservation Board) is a governmental organisation responsible for maintaining wilderness areas and public nature reserves in Western Cape Province, South Africa. Parks managed by CapeNature Wes ...

and private landowners to better preserve and develop high-quality

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

. This project aims at restoring the river ecosystems for sustainable development. The sawfin has been bred in captivity at the Clanwilliam Yellowfish Conservation Station, but captive breeding success is not sufficient and improved techniques are needed.

References

* (2007): Evolutionary origin of Lake Tana's (Ethiopia) small ''Barbus'' species: indications of rapid ecological divergence and speciation. '' Anim. Biol.'' 57(1): 39–48. (HTML abstract) * {{Taxonbar, from=Q2218155 Pseudobarbus Freshwater fish of South Africa Fish described in 1864 Taxa named by Wilhelm Peters Taxonomy articles created by Polbot