This family contains by far the most species in the Iranian freshwater ichthyofauna. Accordingly, the family is split up by genera to make the files of manageable size (see above).

The carp or minnow family is one of the most widespread and speciose families of fishes in the world, certainly the most speciose in fresh water and possibly the largest family of vertebrates (the Gobiidae may be the first). The family is found in North America, Eurasia and Africa. Other common names in English for species include barbels, breams, roaches, snow trouts, bitterlings, shiners, daces, chubs, barbs, "sharks", among many others. There are about 220 genera and over 2420 species (Nelson, 2006), about 8.5% of the world's fishes. In Iran, the family is represented by about 32 native genera (interpretations of genera differ between authors; there will be more if Barbus is split for example) and at least 73 species (with more to be described) found in all the major drainage basins. 

The minnow or carp family is comprised of small to very large fishes (1 cm and up to 3 m, with some of the largest members in Iran) characterised by throat or pharyngeal teeth in 1-3 rows, with a maximum of 8 teeth in a row, tooth counts and form are often characteristic of the genus or species, no jaw teeth, body form various from fusiform to compressed, lips are usually thin and not sucker-like (but can show hypertrophy), the upper jaw is bordered by the premaxillae bones and usually protrusible, barbels are absent or present in 1-3 pairs (not more than 2 pairs in Iranian species), body covered in cycloid scales, in some species easily lost, while the head is scaleless, no adipose fin, the anterior 4 vertebrae are modified for conduction of sound from the air bladder to the ear and are known as the Weberian apparatus, pelvic fins are abdominal in position, no pyloric caeca, air bladder usually present and well-developed, connected to the gut by a duct, and not enclosed in a bony capsule, no true stomach, branchiostegal rays always 3 in number, no true spines in the fins although in some the last unbranched dorsal fin ray (at the front of the fin) may be thickened and spine-like and in Cyprinus and Carassius the last unbranched anal ray is also thickened. The primitive chromosome number is 2n=50 but polyploidy is common and seen in Cyprinus, Carassius and in the schizothoracines. Collares-Pereira (1994) argues that the polyploid condition (e.g. 2n=100) is primitive or plesiomorphic.

There are 2-4 unbranched rays (including rudimentary ones) in the dorsal and anal fins followed by the more numerous branched rays (the last two branched rays are counted as one). The first pectoral and the first pelvic fin ray are unbranched and not included in counts. Pharyngeal teeth lie on a modified, fifth gill arch which can be seen or probed behind the shoulder girdle, just inside the gill opening. The arch has to be removed with dissecting equipment to count the teeth. Tooth counts are presented as a formula such as 2,5-4,1 which indicates 2 teeth in the outer left row and 4 on the inner right row. Teeth may be lost from major or minor rows so variant formulae are given after the principal one. A horny pad on the underside of the basioccipital bone of the skull is used to masticate the food against. Tooth form varies with the food - molar-shaped teeth are used to crush molluscs, flat but grooved surfaces for grinding plant food and sharp edged teeth for slicing various invertebrate foods.

Two subfamilies, the Alburninae and Leuciscinae, are paraphyletic but together seem to form a monophyletic group with a radiation about 20 million years ago, based on allozyme, cytochrome b, 16S rDNA and mitochondrial control region data from European cyprinids (Hänfling and Brandl, 2000; Gilles et al., 2001). These two subfamilies contain many Iranian genera. Zardoya and Doadrio (1999) analysed the cytochrome b nucleotide sequence of a variety of cyprinids, mostly European, and found support for two subfamilies Cyprininae (including barbins) and Leuciscinae (including cultrins, tincins, gobionins, phoxinins and alburnins + leuciscins). The origin of cyprinids is estimated at 38.9MYA and the separation of Cyprininae and Leuciscinae at 27.7MYA. They also found the phylogenetic utility of barbel possession to be limited as they were acquired independently in the two subfamilies. The number of rows of pharyngeal teeth were a more reliable phylogenetic marker, at least at the generic level.

Durand et al. (2002) using cytochrome b DNA of Cyprinidae conclude that the the Middle East is an important interchange area for this freshwater ichthyofauna rather than a centre of speciation. The Middle East leuciscine cyprinids have Europe as an important Palearctic influence consistent with the Lago Mare dispersion while the the cyprinine cyprinids show three highly divergent lineages, namely one shared with the Euro-Mediterranean area (Barbus/Luciobarbus), a relict of the Lago Mare dispersion, one shared with Africa (Carasobarbus/Varicorhinus subgenus) and one with Asia (Garra). The Lago Mare dispersion occurred during a salinity crisis in the Mediterranean Sea 5.5 MY ago in the Late Miocene when freshwater fish were able to disperse through oligohaline or fresh water in the Paratethys Sea to reach the Middle East (Bianco, 1990). Some data of Durand et al. (2002) conflict with this scenario - the Carasobarbus clade that includes Barbus grypus shows a separation divergence later than the salinity crisis in the Pliocene when no migration route was available. But note that some authors place Barbus grypus in the Indian genus Tor and that evidently more work needs to be done on its relationships and on those of other species that have no evident Euro-Mediterranean relatives, but whose origins may well lie in the Oriental Region.

Other Middle Eastern cyprinid genera are regarded by Durand et al. (2002) as relicts of older colonization waves and show an eastern influence consistent with an Asian origin of the family Cyprinidae. Cyprinion has no sister species in the Euro-Mediterranean area and has been isolated in the Middle East since before the salinity crisis, 7.8-8.8 MY ago. Cyprinion may have entered the Middle East during the colonization event that isolated the genera Barbus and Schizothorax in the European and Asian basins respectively. The divergence of these species is similar in time to the radiation of the Leuciscinae supposedly centred in Siberia based on fossil records. Siberia was probably an important dispersion centre for both Leucicinae and Cyprininae at that time. Otero (2001) describes a ?Barbus sp. (sic) from the Lower Miocene of Saudi Arabia showing an early date for the entry of cyprinids to the Afro-Arabian Plate.

Some species may enter brackish water but the family is primarily a freshwater one. Carps have extremely sensitive hearing via the Weberian apparatus and this is thought to account for their success. Carps produce an "alarm substance" when injured. This chemical stimulates other carps to flee and hide, another useful adaptation. Carps are remarkable for changes they undergo during the spawning season. Some fish, which are usually silvery, develop bright reds and yellows. Nuptial, pearl or breeding tubercles develop on the head, scales and fin rays often in distinct patterns, and there are swellings of the head or fin rays in some species. These changes are most apparent in males. Tubercles and swollen rays are used to clasp females during the spawning act. Generally males have longer pectoral fins than females. Tubercles are also used to fight other males and defend and clean nests. Colour attracts females for mating. Nest building males are larger than females, the reverse of the situation in most fishes where egg-bearing females are the largest. Not all species build nests and some simply broadcast eggs over weed, gravel or sand. Fractional spawning is common in carps. This is a prolonged spawning season which ensures no single batch of eggs is lost to unfavourable, temporary environmental changes such as floods. Carps are mostly omnivores, feeding on small crustaceans, insects and some minute plants but some specialise in eating large plants, or other fishes. Diet is reflected in pharyngeal tooth shape as mentioned above. Gut length is important too. A long intestine indicates a reliance on plant material which takes longer to digest. A simple, s-shaped gut is found in insectivorous fish. A black peritoneum is thought to protect gut bacteria from damaging light. The bacteria aid in breaking down the strong cell walls of plants. Size and shape of the mouth are also indicative of diet. Carps are found in many diverse habitats from swift, cold streams to warm bogs. These are schooling fishes, especially when young.

Carps play an important role in fresh waters as food for other fishes and some species are commercially important as bait fish, as sport fish or as food in Asian countries. Raising minnows as bait and as forage fish for sport fish is a big business in the U.S.A. They are an important element in the commercial aquarium trade and certain species are used in experimental studies by scientists. Cyprinids were also important in the past, sacred fish ponds being reported from Mesopotamia in 3000 B.C., and in Iran today cyprinids associated with mosques and shrines are "sacred". A general review of Eurasian cyprinids is given by Bănărescu and Coad (1991).

Carp family members are particularly important in Iran in aquaculture. The "Chinese carps" (Cyprinus carpio or common carp, also native to Iran, Ctenopharyngodon idella or grass carp, Hypophthalmichthys molitrix or silver carp, and to a lesser extent Hypophthalmichthys nobilis or bighead carp) are the main species used in warmwater culture in almost all the provinces of Iran. Common, grass and silver carps are processed into fish fingers in Iran (Iranian Fisheries Research Organization Newsletter, 25:1, 2000). Danesh-e-Khoshashi (1998) describes facilities and methods used for spawning Chinese carps in Gilan Province. The production of Chinese carp fingerlings has been relinquished to the private sector in Iran. The silver carp catch increased from none in 1989 to 24,720 t in 1994 (Food and Agriculture Organization, Fisheries Department, 1996). Chinese carp fingerling production was 22.7 million in 1996 (Bartley and Rana, 1998a). Stakei (1999) studied nutrients, BOD and COD in manured polyculture ponds with Chinese carps. A review of world cyprinid culture, with special reference to the Chinese carps, is given by Billard (1995).

Rana and Bartley (1998a) give details of carp aquaculture in Iran. They note that silver carp production increased 11% per year between 1991 and 1996 and bighead carp 7%. Most carp production occurs in the provinces of Gilan, Mazandaran and Khuzestan and is a private sector enterprise. Carp broodstock is selected based on head size, colour and gill structure (surface and shape). Adults are replaced after 3-4 years. Circular concrete tanks are used for spawning and have egg collecting and incubation devices which reduce handling to the minimum. The young carp are grown to market size in ponds or complex fish farms. In 1994, there were 2583 registered farms with a water surface area of about 8000 ha. Organic and inorganic fertilizers are used along with supplementary foods. Fertilizers include urea (135-1500 kg/ha/yr), ammonium phosphate (80-575 kg/ha/yr) and manure (3-10 tonnes/ha/yr). Supplementary diets include a variety of grains (100-6000 kg/ha/yr) or, for intensive monoculture of common carp, high protein pellets (30-40%). Fingerlings are stocked in March-April at a density of 2000-6000 per hectare and sold between November and February. Production is 1.6-5.5 tonnes/ha. Cultivated carps are susceptible to fungal infections as detailed by Ebrahimzadeh et al. (2000) for the Safid River Fish Farm Centre where 31 species of fungi were isolated.

Rice fields in Iran are now being considered for fish culture. Experimental production of 300-500 kg per hectare of "carp seed" (presumably young fish) an 750-1000 kg of fish and ducks in the autumn after the paddy is harvested (Iranian Fisheries Research Organization Newsletter, 22:2, 2000). In the early 1970s intensive carp culture yielded only half the profits of rice culture (Carl Bond archives, Oregon State University, Corvallis).

Experiments in the Caspian region for artificial propagation of Aspius aspius and Barbus brachycephalus to enhance stocks and for farming Rutilus frisii and Abramis brama using mono- and polyculture along with Chinese carps have been carried out (Iranian Fisheries Research and Training Organization Annual Report, 1992-93; Annual Bulletin 1993-94, Iranian Fisheries Research and Training Organization, Tehran, p. 77-78, 1995). There are about 3000 fish farms producing over 98% of the cultured fish in the country. Yearly production of all cultured fish has increased from 4753 tonnes in 1985 to 45,134 t in 1990. Production of carps in government hatcheries has risen as follows: 2.19 million fingerlings in 1983, 5.04 million in 1984, 12.84 million in 1985, 20.83 million in 1986, 19.05 million in 1987, 50.00 million in 1988, 50.80 million in 1989, 97.70 million in 1990, 58.00 million in 1991, and 50.00 million in 1992. In addition private sector production probably equals these figures (Emadi, 1993a). Polyculture of common, bighead and silver carp has been tried in Iran (Kamaly, 1991). Fish were stocked in four 200 sq m ponds at three densities in polyculture (2700, 3750 and 4750 by species) and at one density in monoculture (9500) fish per hectare. Bighead and silver carp attained a mean weight of 526 and 498 g in polyculture and common carp averaged 343, 190 and 100 g in the same culture but only 13.6 g in monoculture. The growth rate in summer averaged 94.4, 93.7 and 76.1% for silver, bighead and common carp in polyculture and 71.9% for common carp in monoculture. Pen culture in the Caspian Sea has been investigated for Cyprinus carpio and the various Chinese carps (Iranian Fisheries Research and Training Organization Annual Report, Tehran, 1992-93). Semi-artificial breeding of grass, silver and bighead carps has been carried out in Iran (Iranian Fisheries Research and Training Organization Newsletter, 6:3-4, 1994; Annual Report, 1994-1995, Iranian Fisheries Research and Training Organization, Tehran, p. 39, 1996). Hormone injections were used to induce breeding of fish held in a round trough for spawning with a rectangular egg collection trough and a round egg hatching trough. Spawning occurred within 6.5-12.5 hours of injection. The percentage of hatched larvae in this semi-artificial method was higher than a control artificial method where eggs are kept in incubators. The increase was 6% for grass carp, 33.72% for silver carp and 16.7% for bighead. Active larvae increased from 180,000 to 450-500,000 for grass carp, from 157,000 to 400-450,000 for silver carp and from 680,000 to 970,000 for bighead carp. Additionally female breeder mortality was 3.37% less for grass carp and 45.19% less for silver carp.

Many carp species can be caught on hook and line by various angling techniques but outside the larger rivers of Khuzestan and the Caspian shore this hobby is not much pursued. Even small species and specimens can give some sport on light tackle such as worm baited hooks including Barbus barbulus, Barbus luteus, Alburnus mossulensis, Cyprinion macrostomum and Garra rufa among others.

Fingerlings of Labeo rohita, an Indian carp, were imported to Gilan in Iran in 2004 to enrich the diversity of cultured fish and increase protein production. There is always the potential for escapes and establishment of this exotic.

Top

© Brian W. Coad (www.briancoad.com)