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

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Cyprinidae Cyprinidae is a family of freshwater fish commonly called the carp or minnow family, including the carps, the true minnows, and their relatives the barbs and barbels, among others. Cyprinidae is the largest and most diverse fish family, and t ...

. It was formerly placed with the South African 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", i ...

''. It is

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

. Its closest living relative is the

Cape whitefish The Cape whitefish or Berg-Breede River whitefish (''Cheilobarbus capensis'') is a ray-finned fish species in the family Cyprinidae. It was formerly placed with the South African redfins in ''Pseudobarbus''. It is tetraploid. Its closest living ...

(''C. capensis'').de Graaf ''et al.'' (2007) This sizeable

cyprinid Cyprinidae is a Family (biology), family of freshwater fish commonly called the carp or minnow family, including the carps, the true minnows, and their relatives the barb (fish), barbs and barbel (fish), barbels, among others. Cyprinidae is the ...

can grow to over long and weigh more than .

Distribution and ecology

It is

endemic Endemism is the state of a species being found only 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 foun ...

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 inhabi ...

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

tributaries A tributary, or an ''affluent'', is a stream or river that flows into a larger stream ('' 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 into which the ...

. Its range has decreased throughout most of the 20th century, and 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

foothill Foothills or piedmont are geographically defined as gradual increases in elevation at the base of a mountain range, higher hill range or an upland area. They are a transition zone between plains and low relief hills and the adjacent topograp ...

s, adults will move further down to where the rivers enter the

coastal plain A coastal plain (also coastal plains, coastal lowland, coastal lowlands) is an area of flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and an upland area. Formation Coastal plains can f ...

and the water is deeper. The sawfin is

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

, but mainly eats aquatic

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s and their

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

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

school A school is the educational institution (and, in the case of in-person learning, the Educational architecture, building) designed to provide learning environments for the teaching of students, usually under the direction of teachers. Most co ...

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

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

, where they

spawn Spawn or spawning may refer to: * Spawning, 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: Armageddon' ...

. This

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.

Status and conservation

This species is considered

Near Threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...

by the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

, as it has declined much between the 1930s and 1970s. This seems to have been mainly due to the introduced

smallmouth bass The smallmouth bass (''Micropterus dolomieu'') is a species of freshwater fish in the Centrarchidae, sunfish family (biology), family (Centrarchidae) of the order (biology), order Centrarchiformes. It is the type species of its genus ''Micropterus ...

(''Micropterus dolomieu''), which can kill off entire

subpopulation In statistics, a population is a 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 galaxy) or a hypo ...

s by eating the juveniles. Clanwilliam yellowfish (''Labeobarbus seeberi'') 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 Body of water, water bodies, with a negative impact on their uses. It is usually a result of human activities. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and ...

and overuse, mainly due to

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

. 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, Matjies River Nature Reserve and Oorlogskloof Nature Reserve. In 2004, the Greater Cederberg Biodiversity Corridor was established by CapeNature and private landowners to better preserve and develop high-quality

habitat In ecology, habitat refers to the array of resources, 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 manifestation of its ...

. This project aims at restoring the river ecosystems for

sustainable development Sustainable development is an approach to growth and Human development (economics), human development that aims to meet the needs of the present without compromising the ability of future generations to meet their own needs.United Nations General ...

. 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 Taxobox binomials not recognized by IUCN Freshwater fish of South Africa Fish described in 1864 Taxa named by Wilhelm Peters Taxonomy articles created by Polbot Sawfin