Genus Scardinius
Bonaparte, 1837

Howes (1981) placed this genus in Rutilus Rafinesque, 1820 on osteological grounds. Bogutskaya (1988) disagrees. Scardinius is usually separated from Rutilus by having 2, as opposed to 1, rows of pharyngeal teeth and a ventral keel on the body. Howes (1981) considers pharyngeal teeth to be of only species importance and the keel is variously developed in Rutilus.

The genus contains perhaps 6 species and is found from the British Isles and the Iberian Peninsula throughout Europe to the Caspian and Aral Sea basins, with one species in Iran.

The genus is characterised by a pharyngeal tooth count of 3,5-5,3 with major row crowns laterally compressed and bearing 5-8 serrations, scales moderate in size in a complete lateral line, few, short gill rakers, a keel on the belly behind the pelvic fins covered with scales, a short gut and light peritoneum, dorsal and anal fins of moderate length, dorsal fin origin well behind the origin of the pelvic fins, terminal and oblique mouth,

Scardinius erythrophthalmus
(Linnaeus, 1758)

Common names

sorkh pareh or sorkh par (= red fin), mahi sorkh baleh, ماهي چشم قرمز (= mahi chesm ghermez).

[giziluzkac in Azerbaijan; krasnoperka in Russian; rudd, redeye, redfin, pearl roach].

Systematics

See above under the genus. Cyprinus Erythrophthalmus was originally described from northern Europe. This species is widely known to spawn with other cyprinid fishes making hybrids a common occurrence. Some Iranian material appears to be hybrids of this species and another, unknown parental species but this has not been investigated.

Key characters

This species is often confused with Rutilus rutilus but can be distinguished by the posterior position of the dorsal fin (in relation to the pelvic fins), the belly keel, the upturned mouth, and the serrated pharyngeal teeth in 2 rows.

Morphology

Dorsal fin with 2-4 unbranched and 7-10, usually 8 branched rays, anal fin with 3-4 unbranched followed by 9-13, usually 11, branched rays (Abdurakhmanov (1962) initially gives 8-9 anal fin branched rays for Azerbaijan fish but this may be a misprint as a subsequent table lists 9-11 rays), pectoral fin with 13-16 branched rays, and pelvic fin with 7-9 branched rays. Lateral line scales 36-45. There is a pelvic axillary scale. Scales are squarish in shape, with sharp dorsal and ventral anterior corners, a wavy anterior margin, central focus, fine circuli which are coarser on the posterior field, and very few anterior and posterior radii (e.g. 2 anterior and 3 posterior primary radii reaching the focus from the margin). The scale margin is indented where radii terminate and the thick posterior radii are visible on the flank. Gill rakers short and widely spaced, touching the adjacent one when appressed, and numbering 8-13. Vertebrae 37-42. Pharyngeal teeth mostly 3,5-5,3 with variants 3,5-5,2, 3,5-5,1, 3,5-4,3, 2,5-5,3 and 2,5-5,2, narrow and elongate, slightly hooked and with about 5-8 strong serrations on each tooth. There is a strongly-developed, scaled keel between the vent and the pelvic fin base. The gut is s-shaped with an anterior loop. The chromosome number is 2n=48-50 (Klinkhardt et al., 1995).

A single Iranian specimen had the following meristics:- dorsal fin branched rays 8; anal fin branched rays 10; pectoral fin branched rays 16; pelvic fin branched rays 8; lateral line scales 37; total gill rakers 10; pharyngeal teeth 3,5-5,3, and total vertebrae 39..

Sexual dimorphism

Males develop breeding tubercles on the head and body.

Colour

The back is blue-black to greenish- or olive-brown, the flanks are brassy and the belly silvery-white. Upper flank scales have dark bases. The tips of the caudal, anal and pelvic fins are a bright, blood red in the spawning season and the dorsal fin is black proximally and red distally. The iris is yellow to orange, or gold, with a red spot at the top. Peritoneum silvery with scattered melanophores. Young are much less brightly coloured than adults.

Size

Attains 46 cm and 2.06 kg.

Distribution

Found from the British Isles and north of the Pyrenees east to the Caspian and Aral sea basins. It is recorded from the Lenkoran in Azerbaijan and, in Iran, from the Anzali Mordab, Bojaagh wetland, Safid River, Haraz River and Babol River (Derzhavin, 1934; Holčík and Oláh, 1992; Abbasi et al., 1999; Abdoli, 2000; Jolodar and Abdoli, 2004; K. Abbasi, pers. comm., 21 February 2005).

Zoogeography

This species is part of a European and West Asian fauna whose origins may lie in a Danubian or Sarmatian fauna.

Habitat

Rudd can favour heavily overgrown areas (Shikhshabekov, 1979) and are generally found in shallow warm lakes or slow moving rivers. They are usually inhabitants of midwater or near the surface but they overwinter in deep water. They are regarded as fairly hardy and are adapted to eutrophic, and presumably therefore, polluted waters. In Iranian waters its density is highest in the Anzali Mordab (K. Abbasi, pers. comm., 21 February 2005).

Age and growth

Sexual maturity is attained at 3-4 years in Dagestan at lengths of 17-29 cm and 80-530 g. A stunted form is found in rice paddies at an age of 2 years, 7.5-11.0 cm and 10-23 g (Shikhshabekov, 1979). Elsewhere life span is at least 17 years.

Food

Food is aquatic macrophytes as well as insect larvae, crustaceans, molluscs and more rarely fish eggs and fry. The young feed on zooplankton.

Reproduction

Spawning takes place at water temperatures of at least 18-20°C in June-July in Dagestan. Each female can be accompanied by two males, one on each side. Two batches of eggs may be spawned in this period (Shikhshabekov, 1979). In the Volga Delta, spawning takes place from April until the end of June. Eggs attach to water plants. The young remain attached to vegetation until the yolk-sac is absorbed. Fecundity is up to 232,000 eggs with a diameter of 1.5 mm. Hatching takes 3 days at 20-22°C.

Parasites and predators

Masoumian and Pazooki (1998) surveyed myxosporeans in this species in Gilan and Mazandaran provinces, finding Myxobolus pfeifferi. Khara et al. (2006b) record the nematode Raphidascaris acus from this species in the Boojagh Wetland of the Caspian coast. The Caspian seal, Pusa caspica, is a predator on this species (Krylov, 1984).

Economic importance

Holčík and Oláh (1992) report a catch of 98 kg in the Anzali Mordab in 1990.

Robins et al. (1991) list this species as important to North Americans. Importance is based on its use in aquaria and aquaculture, as food, in sport and in textbooks and because it has been introduced outside its natural range.

Conservation

Lelek (1987) classifies this species as vulnerable in Europe. Kiabi et al. (1999) consider this species to be conservation dependent in the south Caspian Sea basin according to IUCN criteria. Criteria include sport fishing, medium numbers, habitat destruction, limited range (less than 25% of water bodies), absent in other water bodies in Iran, present outside the Caspian Sea basin. Near threatened in Turkey (Fricke et al., 2007).

Further work

The distribution and biology of this species and its potential for hybridisation with other cyprinids requires study in Iran.

Sources

Iranian material: Uncatalogued, 1, 103.7 mm standard length, Gilan, swamp near Hendeh Khaleh (37°23'N, 49°28'E).

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