The pipefishes and seahorses are found world-wide, mostly in tropical and warm-temperate waters, with some brackish and freshwater species. There are 52 genera and about 232 species (Nelson, 2006) but only one species of pipefish is reported for Iranian fresh waters. Maximum length is about 65 cm. The body of pipefishes is characteristic being very thin and very elongate, and enclosed in bony rings as a form of armour. The body is divided into a trunk and a tail, the tail being prehensile in seahorses. The first trunk ring has the pectoral fin base and the last has the anus in it. The snout is elongate with a small toothless mouth at the tip. Gills are tufted and the gill opening is small. There are 1-3 branchiostegal rays. There is a single dorsal fin without spines, the pelvic fins are absent and the pectoral, anal and caudal fins may be absent too. The caudal is always small when present. The anal fin is always small with only 2-6 rays. Those without a caudal fin may have the tail prehensile, able to grasp and hold onto objects. Pipefishes and seahorses have only one kidney, on the right side. Males usually have a pouch on the belly formed from two skin folds which meet at the mid-line. The female attaches eggs to the male belly or places them in a pouch (or marsupium). Here the eggs develop and eventually leave after about 4-6 weeks through a slit or pore so the male "gives birth".

Pipefishes and seahorses are found mostly in shallow coastal areas and in estuaries but also occur down to about 400 m and in the open ocean often associated with floating seaweed. They are slow-moving because of their armour and easily picked up by hand. Propulsion is by undulating the dorsal and pectoral fins. Since they cannot outswim most predators, they are often very well camouflaged by colour, body form and by appendages which disrupt the body outline. Their food is small crustaceans sucked into the tube-like snout by a sudden expansion of the buccal cavity. Many species have a life span of only about 2 years.

Dried seahorses and pipefishes are commonly sold as curios and some family members have been used as medicines or aphrodisiacs in the East. They are popular aquarium fishes. Certain species are endangered by this collecting for curios, medicines and aquaria.

Genus Syngnathus
Linnaeus, 1758

Members of this genus are found in all seas and there are about 31 species. A single species is found in the Caspian Sea and Iranian waters.

The genus is characterised by a brood pouch in the caudal area of males, running forward to about the origin of the dorsal fin. The eggs develop in isolation from the sea, oxygen diffusing from the "pregnant" male. Dorsal, caudal, anal and pectoral fins are present. The caudal and anal fins are very small.

Syngnathus abaster
Risso, 1826

Common names

ney mahi or naymahi (= reed fish, i.e. as thin as a reed), ney mahi darya-ye Khazar (= reed fish from the Caspian Sea), سوزن ماهي (= suzan mahi, meaning needle fish).

[xazar iynabaligi in Azerbaijan; Kaspiiskaya igla-ryba or Caspian pipefish in Russian; short-snouted pipefish, blackstripe pipefish].

Systematics

Syngnathus abaster was originally described Nice, France.

Syngnathus ponticus Pallas, 1814 described in part from mouths of rivers falling into the Caspian Sea, Syngnathus nigrolineatus Eichwald, 1831 described from "Hab. in sinu Bacuensi, Murdofiensi Caspii maris", i.e. Baku Bay, and also at Odessa on the Black Sea, and Syngnathus caspius Eichwald, 1831 described from "Hab. in sinu balchanensi Caspii maris" (Balkhan Bay in the Caspian Sea), and Syngnathus bucculentus Rathke, 1837 described from Sevastopol and Feodosiya on the Black Sea are synonyms. Lueken (1967) demonstrated that Syngnathus nigrolineatus caspius Eichwald, 1831, the taxon generally referred to in the literature as occurring in the Caspian Sea, is a synonym of Syngnathus abaster.

Key characters

The extremely thin, elongate body encased in bony rings is unique in Iran.

Morphology

Dorsal fin rays 22-43, the count increasing with age; anal fin rays 3, pectoral fin rays 9-15, and total caudal fin rays 8-11. Trunk rings 14-18; tail rings 28-42, and rings under the dorsal fin 5-12. A dorsal ridge ends near the rear of the dorsal fin and a continuation of the mid-lateral ridge becomes the dorsal ridge posteriorly. A mid-belly ridge extends back to the anus where it terminates. As a result the anterior part of the body from the dorsal fin forward has 7 longitudinal ridges, reduced to 4 posteriorly.

Meristic values for Iranian specimens are:- 30(3), 31(6), 32(9), 33(18), 34(13), 35(7), 36(1), 37(1), 39(2), 40(4), 41(3), 43(1); anal fin rays uniformly 3; pectoral fin rays 11(14), 12(22), 13(10), 14(8), 15(1); total caudal fin rays 9(1), 10(51), 11(2). Trunk rings 15(46), 16(18), 17(4); tail rings 33(3), 34(7), 35(28), 36(13), 37(5), 38(6), 39(4), 40(2), rings under the dorsal fin 6(1), 7(28), 8(24), 9(2); and brood pouch rings 15(1), 17(2), 18(3), 19(1), 20(3), 21(1), 22(2), 23(1). Total vertebrae 52(3), 53(2), 54(2), 55(4), 58(1), 59(1).

Sexual dimorphism

Males have a brood pouch under the tail.

Colour

Overall colour is brown to green with dark or light spots and bars arranged in a reticulate fashion on each ring. Pigment is best developed on the dorsal half of the head and body. The ventral part of the tail becomes darkest posteriorly near the tail fin. The reticulate pattern of darker pigment can form a consistent pattern of arcs bounding the plate junctions along both the upper and lower flank such that a double row of dark ovals with light centres is apparent. Behind the dorsal fin where there is no central ridge on the flank, there is a single dark oval at each plate junction. While some fish have this regular pattern of dark ovals, others are more irregular with the ovals filled in with pigment leaving only very small clear patches in the centre. Various other patches of clearer or lighter pigmentation form part of the general reticulate pattern. Additionally, large dark spots or pigment concentrations may be present along the edge of the uppermost ridge anteriorly and small dark spots may be scattered along the back and flanks.

The dorsal fin base can be darkly spotted or striped. The fin itself may be almost immaculate but a few melanophores line the rays. The pectoral fin base has a dark line of merged spots and the rest of the fin is almost immaculate although the rays can be very lightly lined with melanophores. The anal fin is immaculate. The caudal fin is dark on the rays and membranes, in particular on the central part.

Size

Reaches 23 cm total length.

Distribution

Found in the Mediterranean, Black and Caspian seas and the west coast of the Iberian Peninsula. In Iran, it is recorded from the Anzali Mordab and neighbouring rivers, Gorgan Bay, lower reaches of Caspian Sea rivers, the southeast Caspian Sea, southwest Caspian Sea and south-central Caspian Sea, including the deltas of some rivers (Derzhavin, 1934; Holčík and Oláh, 1992; Paateemaar, 1993; Kiabi et al., 1999; Jolodar and Abdoli, 2004).

Zoogeography

Berg (1948-1949) contends that this species entered the Caspian from the Black Sea in post-glacial times while most other Caspian fishes are relicts of earlier transgressions or migrants from northern waters.

Habitat

This pipefish can live and reproduce in water at a salinity of 59.5‰ (Zenkevitch, 1963) and is euryhaline. It is found over sandy or muddy bottoms usually where there is vegetation or detritus, down to about 5 m. Campolmi et al. (1996) consider this species to be a major component of nearshore meadows in Sicily. Juveniles have a benthic distribution for at least 4 weeks after release from the marsupium in Portugal (Silva et al., 2006).

Age and growth

Growth is faster in the first year of life as in the second year energy is used for reproduction. Life span is slightly over one year in northwest Sicily (Campolmi et al., 1994; 1996) and 17 months in the Po River Delta, Italy (Franzoi et al., 1993), or up to 4 years generally. Male:female sex ratio is 1:2.18 in Sicily (Campolmi et al., 1994; 1996) but about 50:50 in the Po Delta (Franzoi et al., 1993). Maturity in the Mauguio Lagoon in southern France is reached as early as 3-4 months and almost all individuals are mature after their first winter (Tomasini et al., 1991).

Food

Campolmi et al. (1994; 1996) found their northwest Sicily population to feed mainly on zoobenthos, 70% being harpacticoids, ca. 18% or less gammarids and caprellids, and ca. 10% or less isopods. Prey hidden in vegetation was taken on account of the short and conical snout which was less effective than the longer snout of other species which feed on more active pelagic prey. Franzoi et al. (1993) in their study found harpacticoids associated with algae to be the most important food item, with up to 87.5% of the diet comprised of only 3 species in 1 genus, Tisbe.

Reproduction

Broods are found from April to October with the first breeding males appearing in March in Sicily, the Po Delta and southern France (Campolmi et al., 1994; 1996; Franzoi et al., 1993; Tomasini et al., 1991).

Reproductive behaviour starts with mutual flickering movements in fish observed in Portugal. This comprised rapid and vigorous bends of the body with both males and females approaching the opposite sex  (Silva et al., 2006). If the opposite flickered in response, the next phase was rapid side-by-side movements while swimming more or less parallel. Flickering increased in frequency and the female's genital papilla protruded. The distended genital papilla is placed in the anterior area of the marsupium of the male, the folds in this area being separated and swollen. The mated pair then ascend slowly in the water column, vibrating the dorsal fin and rotating a few times. Eggs are transferred and the  female retreats to the substratum while the male continues swimming with violent body contractions - these help pack the eggs in the posterior end of the marsupium. Later, spawning occurs again up to three times by the same pair although females may mate with up to 3 different males in less than 30 minutes.

Egg numbers in the Po Delta are 104±40 in females and 109±27 in males. Eggs are yellowish to bright orange and translucent with diameters usually 1.0-1.4 mm, up to 1.8 mm (Tomasini et al., 1991) or 1.09-2.06 mm in Portugal (Silva et al., 2006). Young first appear first in May and are present until August in the Po Delta. This species is a batch spawner in northwest Sicily and southern France and males can incubate several broods during the breeding season since incubation lasts about 1 month (Tomasini et al., 1991; Franzoi et al., 1993; Campolmi et al., 1994; 1996). Females in the Po Delta probably breed only once but the female may parcel out the same egg batch among many males. A male may have several batches of eggs in different stages of development in the brood pouch at any one time. This distribution among several males increases survival (Tomasini et al., 1991). Incubation at 20-21°C in aquaria is about 15 days and a new mating occurs 8 days after the litter (Tomasini et al., 1991). In Portugal, development lasted 24-32 days at 18-19ºC or 21 days at 21-22ºC (Silva et al., 2006). The female potential fecundity per breeding act in southern France averages 21-23 ovocytes while the male brood pouch can accommodate 36-52 eggs. As a consequence the female matures rapidly between two breedings and the species is polygynous (Tomasini et al., 1991). Males carry 10-64 eggs in Portugal (Silva et al., 2006). New-borns are about 13.5 mm long in the Po Delta (Franzoi et al., 1993).

Broods are found in males from Iran collected on 4 May, the same sample having males with eggs and males with minute young pipefish. A sample from 22 September has eggs just about to hatch while males taken on 3 August, 28 September and 17 December contain neither eggs nor young. Females with large eggs have been caught in Iran on 17 April and 7 July while on 3 August, 19 September, and 12 and 17 December females had only small eggs. The 17 April sample contained eggs of dissimilar sizes. Iranian fish appear to have a similar breeding season to those from other localities and probably have batch spawning too.

Parasites and predators

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

Economic importance

None.

Conservation

The ecology of this species has not been studied in detail in Iranian waters and its population is unknown rendering an assessment of its conservation status difficult. Kiabi et al. (1999) consider this species to be of least concern in the south Caspian Sea basin according to IUCN criteria. Criteria include abundant in numbers, widespread range (75% of water bodies), absent in other water bodies in Iran, and present outside the Caspian Sea basin.

Further work

The significance of this species in the ecology of the Iranian coastal region and its biology have not been determined.

Sources

Paateemaar (1993) gives an account of this species in Iran in Farsi. Data were taken from Lueken (1967) and Dawson in Whitehead et al. (1984-1986).

Iranian material: CMNFI 1970-0507, 1, 91.3 mm standard length, Gilan, Caspian Sea at Hasan Kiadeh (37º24'N, 49º58'E); CMNFI 1970-0508, 1, 89.4 mm standard length, Gilan, Safid River at Hasan Kiadeh (37º24'N, 49º58'E); CMNFI 1970-0531, 1, 108.1 mm standard length, Mazandaran, Larim River mordab (36º46'N, 52º58'E); CMNFI 1979-0535, 1, 126.3 mm standard length, Gilan, Shara River estuary (37º35'N, 49º09'E); CMNFI 1970-0543A, 5, 104.6-144.8 mm standard length, Gilan, Caspian Sea at Hasan Kiadeh (37º24'N, 49º58'E); CMNFI 1970-0554, 13, 40.4-95.6 mm standard length, Gilan, Pir Bazar Roga (37º21'N, 49º33'E); CMNFI 1970-0563, 1, 134.9 mm standard length, Gilan, Caspian Sea, Kazian Beach (ca. 37º29'N, ca. 49º29'E); CMNFI 1970-0567, 7, 52.9-99.5 mm standard length, Gilan, Pir Bazar Roga (37º21'N, 49º33'E); CMNFI 1970-0575, 1, 94.3 mm standard length, Gilan, Pir Bazar Roga (37º21'N, 49º33'E); CMNFI 1970-0587, 3, 131.6-140.0 mm standard length, Mazandaran, Babol River near Babolsar (36º43'N, 52º39'E); CMNFI 1971-0343, 3, 104.6-109.0 mm standard length, Langarud at Chamkhaleh (37º13'N, 50º16'E); CMNFI 1979-0077, 8, 128.4-149.2 mm standard length, Mazandaran, Caspian Sea beach at Now Shahr (36º39'N, 51º31'E); CMNFI 1980-0130, 9, 59.3-97.8 mm standard length, Mazandaran, river near Iz Deh (36º36'N, 52º07'E); CMNFI 1980-0136, 16, 76.6-100.5 mm standard length, Mazandaran, Fereydun Kenar River estuary (36º41'N, 52º29'E).

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