Genus Pelecus
Agassiz, 1835

The sabre carp genus contains only a single species found from the Baltic to the Black, Caspian and Aral Sea basins including Iran. The characters of the genus are the same as under the species.

Pelecus cultratus
(Linnaeus, 1758)

Common names

shamshir mahi (= scimitar or swordfish), shamshir mahi ab shirin (= freshwater swordfish), kuli.

[gilincbalig in Azerbaijan; chekhon' in Russian; sichel, ziege, razorfish, sabre carp, sabrefish].

Systematics

Pelecus cultratus was originally described from the Baltic Sea.

Pelecus cultratus kurensis Smirnov, 1943 is the Kura River basin subspecies but Berg (1948-1949) considered that other populations over the range of this species had been insufficiently studied to validate this subspecies.

Key characters

This species is easily recognised by the scaleless keel extending from the throat to the anal fin and the decurved and wavy lateral line.

Morphology

The body is elongate and strongly compressed. The mouth is almost vertical. The pectoral fins are long and curved, used for rapid manoeuvring when swimming normally and folded against the body when swimming rapidly. The lower lobe of the caudal fin is larger than the upper, with more rays and a stiffer ventralmost ray. The lower jaw is hooked in older specimens and has a tubercle which fits into an upper jaw notch. Gill openings are very wide with the branchiostegal membranes attached far forward, under the eye level. Muscles on the back extend forward to reach the anterior eye margin. Dorsal fin unbranched rays 2-3, usually 3, followed by 6-10, usually 7, branched rays, anal fin unbranched rays 2-3, usually 3, and branched rays 23-31, pectoral fin branched rays 13-17, and pelvic fin branched rays 6-8. Lateral line scales 88-120. Scales have extremely fine circuli, a central to subcentral posterior focus and very few posterior radii. Gill rakers number 15-26 (reaching the second or third raker below when appressed) and vertebrae 46-52. Pharyngeal teeth number 2,5-5,2, are narrow and are very strongly hooked at the tip with obviously serrate edges. Variants include 2,5-4,2, 2,4-5,2 and 2,5-5,3. The gut is an elongate s-shape. The chromosome number is 2n=50 (Klinkhardt et al., 1995).

Sexual dimorphism

Unknown.

Colour

The back is greenish and the flanks silvery. Fins are hyaline to grey, although the paired fins and the anal fin can be a bright yellow.

Size

Reaches 60 cm and 3.5 kg but most fish in the Volga-Caspian region are 80-180 g.

Distribution

Found in the drainages of the Baltic, Black, Caspian and Aral seas. This species is reported as rare in the lower Safid River (Derzhavin, 1934) and is found in the Anzali Mordab (Abbasi et al., 1999; Kiabi et al., 1999). Recorded by Abdoli (2000) from the middle to lower Safid River, Anzali Talab and adjacent Caspian coast. Recorded from the Atrak River but not yet from its Iranian reach (Reshetnikov et al. (1997). Also reported from the Karakum Canal and Kopetdag Reservoir of Turkmenistan (Shakirova and Sukhanova, 1994; Sal'nikov, 1995) and so may eventually be found in the Tedzhen (= Hari) River basin of Iran.

Zoogeography

A European and western Asian species with its origins in a Danubian or Sarmatian fauna.

Habitat

This species lives primarily in the sea but is also anadromous and may live permanently in larger tributaries. Jolodar and Abdoli (2004) note two forms in Iran, one resident in fresh water and a migratory form. It inhabits surface waters, aided by fin and mouth modifications for this mode of life (Adamicka, 1984). It migrates to the fresh water of large rivers to spawn. In the sea and larger rivers it occurs in schools.

Age and growth

Sexual maturity in the Volga River is attained at 3-4 years and a minimum length of 20 cm in males, 4-5 years and 22 cm for females. The largest immature males are 24 cm long, females 25 cm and the maximum age of non-spawners of both sexes does not exceed 6 years. The spawning stock is mostly fish 4-10 years old. Males have a slightly smaller maximum size than females and life span is at least 16 years (Sil'chenko, 1976). Spawning takes place first at age 2 in the Kura River of Azerbaijan. Growth is faster than in other populations, the Kura fish being the same size at age 2 as age 3 fish from the Don River of the Black Sea and age 4 fish of the Aral Sea.

Food

Food is taken by the vertical mouth from surface waters and includes insects and spiders. Young fish feed on zooplankton and even adults will do this if crustaceans are abundant. In the sea, various crustaceans are taken and these may be pursued near the bottom. Full grown Pelecus (50-60 cm) will capture fish such as Clupeonella, gobies (Gobiidae), Cyprinidae and even sticklebacks (Gasterosteidae) (Adamicka, 1984).

Reproduction

Spawning takes place in the latter half of May in the Kyubyshev Reservoir of the Volga River at 13.5-14.1°C or as high as 18-22°C. Water depths are 2.0-3.5 m. The main spawning takes place around sunset over a period of 24 days with a peak period of 10-12 days. Fecundity reaches 71,400 eggs. Eggs sink to the bottom but swell to an average diameter of 4.7 mm within an hour of fertilisation. Once swollen, any slight movement of the water will suspend the eggs in the water column. Eggs develop pelagically in floodplains, main rivers, side channels, bays and lakes but all these diverse habitats have a high oxygen content through flowing water or wind mixing. In the Volga flow rates are 0.28-1.1 m/sec on a sand-gravel bottom. Spawning may also take place in brackish water where the eggs float. Spawning in the Kura River of Azerbaijan takes place at the end of April and in May. The larvae are phototropic and active swimmers.

Parasites and predators

The Caspian seal, Pusa caspica, is a predator on this species (Krylov, 1984).

Economic importance

Robins et al. (1991) list this species as important to North Americans. Importance is based on its use in textbooks and for food. The scales contain silvery crystals of guanine which are extracted and used to make essence d'orient for artificial pearls. In the period 1909-1913, the catch in the Volga-Caspian region was more than 14 million fish annually. The flesh is fatty and bony and so this species is best smoked.

Conservation

Lelek (1987) classifies this species as intermediate to rare in Europe but fairly common in the Caspian Sea basin. Kiabi et al. (1999) consider this species to be critically endangered in the south Caspian Sea basin according to IUCN criteria. Criteria include sport fishing, few in numbers, habitat destruction, limited range (less than 25% of water bodies), absent in other water bodies in Iran, and present outside the Caspian Sea basin.

Further work

The distribution and biology of this species in Iranian waters needs study although it is probably too rare to be easily captured in numbers.

Sources

Meristics based partly on Wais (1995).

Iranian material: None available.

Comparative material: CMNFI 1971-0825, 1, 232.0 mm standard length, Czechoslovakia, Lake Ozirna (no other locality data); CMNFI 1987-0220, 2, 96.9-105.7 mm standard length, Rumania, Lake Călăraşi (44º20'N, 27º20'E).

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