Sticklebacks are found in marine and fresh waters of the cooler parts of the Northern Hemisphere. There are about 8 species of which one is native to Iran and another has been introduced.

This family of small fishes is characterised by a compressed, fusiform body; teeth in bands in each jaw but none on the tongue or palate; a protractile mouth; 3 branchiostegal rays; no postcleithrum; no scales but a series of plates along the flank variably developed, sometimes absent; 2 or more (usually 3-16) isolated spines in front of a soft dorsal fin (usually 6-14 rays); and a pelvic fin with a strong spine and only 0-2 soft rays.

The species in this family have been studied extensively (Coad, 1981f; Paepke, 1983; Wootton; 1976; 1984; Paepke in Bănărescu and Paepke, 2002). There is variation in colour, body form, spine numbers and development, and plate numbers. These variations in anatomy are matched by variations in biology such as habitat, feeding and reproduction. Variation in behaviour, biology and in speciation makes these small fishes, which have no commercial value, particularly important. Some of the variation is owing to environmental factors while some has a genetic basis. Several books have been devoted to them and thousands of scientific studies. Sticklebacks make excellent aquarium fishes. Their reproductive behaviour is complex, involving courtship and nest building. Some populations are anadromous and enter fresh water to breed.

Genus Gasterosteus
Linnaeus, 1758

This genus is characterised by having a modal count of 3 isolated strong spines in front of the soft dorsal fin, the body usually has strong bony scutes along the flank developed as a keel on each side of the caudal peduncle, a strong spine in the pelvic fin, and a complex reproductive behaviour.

The threespine stickleback, and related populations which act as good species but have not been formally named, have been studied extensively for their reproductive and other behaviours and for the insights that morphological variation and genetics throw on evolution.

Gasterosteus aculeatus
Linnaeus, 1758

Common names

سه خار seh khar (= threespine), سه خاره (= seh khareh or sehkhareh), mahi seh khareh.

[trekhiglaya kolyushka or threespine stickleback in Russian; threespine stickleback].

Systematics

Gasterosteus aculeatus was originally described from Europe. The complex systematics of sticklebacks are not reviewed here. The Iranian specimens appear to be of a "marine" form with well-developed scutes on the flanks but their origin is not known.

Key characters

The 3 strong dorsal spines, strong pelvic fin spine with a single cusp at the base and the row of plates along the flank are distinctive.

Morphology

First dorsal fin comprised of usually 3 spines (2-4), second dorsal fin with 1 spine and 7-14 soft rays, anal fin with 1 spine and 6-13 soft rays, pectoral fin with 8-11, usually 10, branched rays and pelvic fin with 1 spine and 1 soft ray. Gill rakers 14-27, elongate and reaching as far as the fourth adjacent raker when appressed. Vertebrae 27-36. Plates along the flank 30-37; the Iranian specimens have a complete row of flank plates and a well-developed caudal peduncle keel, other populations may have an incomplete row or no plates at all. This species is very widespread and extremely variable over this range in the characters listed above and may well exceed the limits cited, e.g. dorsal fin spines are absent in some fish but the Iranian fish are of the typical marine form. The chromosome number is 2n=42 (Klinkhardt et al., 1995). The gut is short and s-shaped.

An Iranian specimen had 3 dorsal fin spines and 10 soft rays, 1 anal fin spine and 7 soft rays, 10 pectoral in rays and 1 spine and 1 soft ray in the pelvic fin. Scutes, including those forming the caudal peduncle keel, numbered 32. Total gill rakers numbered 19.

Sexual dimorphism

Breeding males develop a red belly and throat, blue sides, light blue back and have bright blue or turquoise eyes.

Colour

Marine populations are more silvery on the flanks than freshwater ones which are more olive. Generally the back is green-brown, olive or grey to blue-black, flanks olive to silvery and the belly silvery-white. Fins are generally clear. The peritoneum is silvery with large, widely spaced melanophores. Stream-dwellers have an irregular pattern of dark spots on the flanks and the back is an iridescent dark green.

Size

Reaches 11.0 cm.

Distribution

Found around the Northern Hemisphere in fresh and marine waters. Reported as an introduction to Iran by Abdoli (1993a, 1993c) and Coad and Abdoli (1993b), this species is found at the Neka Power Plant in Mazandaran near Behshahr, the Tajan River, the lower Gorgan River and Gorgan Bay, Gomishan Lagoon, the lower Babol, Heraz, Chalus, Tonekabon, Langarud Polarud and Safid rivers, the Anzali Talab and the southeast Caspian Sea, the middle to upper Kashaf River in Khorasan, and the upper Kal Shur and upper Jomein.rivers in the Kavir basin (Abbasi et al., 1999; Kiabi et al., 1999; Abdoli, 2000; K. Abbasi, pers. comm., 2001; Jolodar and Abdoli, 2004; Niksirat et al., 2006). It is also caught by herring fishery ships on the coast of Iran (K. Abbasi, pers. comm., 2001).

Zoogeography

The exotic origin of the Iranian population is not known but the complete row of plates suggests a marine population. Sal'nikov (1995) reports this species from the southeastern Caspian Sea and moving into the Atrek River in Turkmenistan in large numbers. He refers to it as the Black Sea-Azov three-spined stickleback but it is unclear whether by this is meant its origin, its dispersal route or simply the nearest natural habitat for the species.

Habitat

These sticklebacks inhabit inshore coastal waters, lakes, ponds, rivers and streams, and may be anadromous. Marine and lake fish can be pelagic. They are often found among algae. In Iran, this species is caught at 30-100 m by herring fishery ships (K. Abbasi, pers. comm., 2001).

Age and growth

Maximum life span is a little over 3 years although some fish probably live only 1 year and a few months, dying after they spawn. Paepke in Bănărescu and Paepke (2002) is a recent review of literature. Esmaeili and Ebrahimi (2006) give a significant length-weight relationship based on 500 Iranian fish measuring 3.60-7.20 cm standard length. The a-value was 0.0090 and the b-value 3.428 (a b-value < 3 indicating a fish that becomes less rotund as length increases and a b-value >3 indicating a fish that becomes more rotund as length increases).

Food

Food is various crustaceans, aquatic and terrestrial insects, snails, worms, fish eggs and fry including their own species, and a wide variety of other available organisms taken both on the bottom or pelagically. Copepods and chironomids tend to dominate as food items. Again Paepke in Bănărescu and Paepke (2002) is a recent review of literature.

Reproduction

Spawning occurs from April to October, varying with locality over the wide range of this species. The male parental cycle at one site in Canada lasts 9-15 days with female interspawning intervals of 19 days. Males and females only complete one spawning here, though laboratory studies show males capable of 5 reproductive cycles and females of producing a clutch of eggs every 3-4 days. Harsh physical conditions are probably the cause. The male builds a barrel-shaped nest in shallow, sandy areas from plant fragments glued together on the bottom with kidney secretions. The nest is in an open area but near vegetation. The nest has an opening at each end. The male has a complex courtship dance with zig-zag motions and a leading motion to the nest. A responsive female adopts a submissive head up position, which also reveals the egg-swollen belly. The male pokes his snout at the nest to indicate its position to the female, tipping his head sideways to display the bright red throat. The male jabs the female with his snout through the nest wall after she enters to stimulate egg release. He then follows the female through the nest to fertilize the eggs and drives the female away. Several females may spawn in one nest which can contain up to 1026, yellowish 1.8 mm diameter eggs. The male guards and fans the eggs and guards the fry.

Parasites and predators

Many fishes and birds, and even snakes, seals and small mammals, feed on sticklebacks despite their protective spines which are locked erect when they are disturbed. Niksirat et al. (2006) record Corynosoma strumosum in this species from the Gomishan Lagoon.

Economic importance

The threespine stickleback has received much attention for its evolutionary interest, behaviour and utility as an experimental fish. They may be predators on fish eggs and larvae, and competitors for food, of more commercially important species. The Baltic Sea area has had sufficient numbers to support an oil extraction industry (Paepke in Bănărescu and Paepke, 2002).

Conservation

Lelek (1987) classifies this species as intermediate to rare, locally vulnerable in Europe. As a recently recorded exotic species in Iran it is still comparatively rare but should not be accorded any status.

Further work

The spread of this exotic species should be monitored and its effects on native fishes observed.

Sources

Iranian material: CMNFI 1993-0144, 1, 57.3 mm standard length, Mazandaran, Neka Power Plant (36º51'48"N, 53º23'24"E).

Genus Pungitius
Coste, 1848

This genus of sticklebacks is found in North America and Eurasia with about 3-5 species (opinions vary) but only 1 in Iran (Paepke in Bănărescu and Paepke, 2002).

It is distinguished by a series of 7-12 small spines (much smaller than in the genus Gasterosteus) in front of the dorsal fin, arranged alternately to the left and right, the pelvic fin has 1 spine and 0-1 soft rays, and the skin is naked or has small bony plates in a row along mid-flank.

Pungitius platygaster
(Kessler, 1859)

Common names

nohkhar or nokhareh (= ninespine), mahi seh khareh nama (= threespine-like fish), mahi khardar (= spiny fish).

[tikan balig in Azerbaijan; malaya yuzhnaya kolyushka or southern ninespine stickleback in Russian; Ukrainian stickleback].

Systematics

Gasterosteus platygaster was originally described from Odessa and Aleshki on the Dnieper in the Ukraine.

Gasterosteus pungitius var. Kessleri Yakovlev, 1870 and Gasterosteus pungitius var. niger Yakovlev, 1870 both from lakes near Astrakhan, Volga River delta, Russia, Gasterosteus platygaster var. caucasicus Kessler, 1877 from Transcaucasia, and Pygosteus platygaster nuda Berg, 1905 from Lake Charkhal in the Ural River valley, are synonyms. Syntypes of the latter are in the Zoological Institute, St. Petersburg (ZISP 10613) (Eschmeyer et al., 1996; Kottelat, 1997).

Münzing (1969) retains this taxon as a distinct species but suggests that it may only be a subspecies of Pungitius pungitius (Linnaeus, 1758). Ziuganov and Gomeluk (1985) studied hybridisation of this species and P. pungitius under experimental conditions and consider that they are at most subspecifically distinct. They found 9 out of 19 morphological characters distinguish this species from P. pungitius as well as a differing ecology. However there were no ethological, nor presumably genetical, isolating mechanisms since F₃ hybrids were fertile. Ziuganov (1991), Keivany (1996), Keivany and Nelson (1997) and Keivany et al. (1997) recognise P. platygaster as a distinct species since it is 100% distinguishable from other species in the genus. However, Keivany and Nelson (2004) found that P. platygaster lay within a polychotomy with subspecies of P. pungitius. P. platygaster is retained as a full species until the two taxa come into contact naturally, which will test the hypothesis of Ziuganov and Gomeluk (1985).

Key characters

The small spines usually alternating left and right in front of the dorsal fin are distinctive.

Morphology

Characterised by 22-34 bony plates along the flank, perhaps a response to predators (Ziuganov and Gomeluk, 1985). The first 4-12 plates are large (Keivany and Nelson, 1998). There is no caudal peduncle keel. The plates in young fish are minute fragments of bone and difficult to see, especially posteriorly. The body form is less elongate than the related Pungitius pungitius. Dorsal fin spines slightly curved, 7-11 (in Iranian specimens 8(7), 9(11)) and branched rays 6-11, anal branched rays 6-10, pectoral fin rays 9-11 (usually 10), and pelvic fin with 1 serrate spine and 0-2 soft rays, usually 1. Rarely up to 4 dorsal fin spines may follow the midline and not alternate markedly in Iranian fish. The last spine in the series is usually slightly longer than the others. Vertebrae number 29-31 (in Iranian specimens 29(9), 30(9)) and gill rakers 7-13, reaching the base of the second raker below when appressed. The gut is short and s-shaped. The chromosome number is 2n=42 (Klinkhardt et al., 1995).

Sexual dimorphism

Colour at breeding is the most evident sexual dimorphism.

Colour

Females are olive with greenish-brown stripes, patches and mottling even during spawning. Males are jet black and develop a blue-white colour on the posterior side of the ventral spines as a stimulus for leading the females. The specimens described as var. kessleri were light grey and var. niger were black, perhaps non-spawners and spawners. The peritoneum is silvery.

Size

Attains 7.0 cm standard length.

Distribution

Found in the Black, Caspian and Aral seas and their basins. Reported from the southeast Caspian Sea, southwest Caspian Sea and south-central Caspian Sea, the Anzali Mordab, Ameerkalaye Lagoon near Lahijan, and lower reaches of rivers (Derzhavin, 1934; Holčik and Oláh, 1992; Nejatsanatee, 1994; Abbasi et al., 1999; Kiabi et al., 1999). Keivany (1996) considers it to be rare on the southern Caspian Sea coast. Jolodar and Abdoli (2004) report it from brackish portions of the Caspian Sea and rivers falling into it, being more numerous in the Gomishan Lagoon.

Zoogeography

Pungitius platygaster aralensis (Kessler, 1877) is reported from the western Uzboi lakes in Turkmenistan (Shakirova and Sukhanova, 1994) and with canal construction projects may ultimately reach the Caspian Sea basin.

Habitat

Described as a benthivore living a cryptic life in weed beds (Ziuganov and Gomeluk, 1985). It can be found in fresh and brackish waters.

Age and growth

In the Volga delta, mature adults are 3.2-5.8 cm long (mean 4.0 cm) from April to July and young-of-the-year are 1.2-2.8 cm long (mean 2.3 cm). Life span appears not to exceed 2 years as only sexually mature adults are caught in spring (Fortunatova, 1961) although a few fish may reach 3 years and maturity may be attained shortly before reaching 1 year (Paepke in Bănărescu and Paepke, 2002).

Food

Diet is small invertebrates including chironomids. Eggs of commercially important fishes may be eaten.

Reproduction

Reproduction can occur at high temperatures, e.g. 28°C, at which eggs of P. pungitius die. Spawning begins at 17°C. In the Volga delta spawning begins in late April and continues to the middle of June but is most intensive in the middle of May. Dense schools are formed which disperse after spawning with the fish becoming secluded in the heavy vegetation which develops at this time (Fortunatova, 1961). Fecundity is up to 90 eggs. Males build nests out of the remains of the previous year's vegetation glued together with kidney secretions (Fortunatova, 1961). A female indicates readiness to spawn by a head-up posture near the nest. The male performs a zig-zag dance and leads the female to the nest entrance by angling his head down at 60°, flashing his blue-white pelvic spines and moving by short jerks. The female enters the nest, the male taps her caudal peduncle to stimulate egg deposition, she leaves and the male enters the nest to fertilize the eggs. The leading part takes only 10 seconds.

Parasites and predators

The Caspian seal, Pusa caspica, is a predator on this species (Krylov, 1984) as are such fishes as Perca fluviatilis, Esox lucius, Silurus glanis, Aspius aspius and Sander lucioperca (Fortunatova, 1961) and Neogobius melanostomus, water snakes, pond turtles, frogs and fish-eating birds (Ziuganov, 1991).

Economic importance

None; although Paepke in Bănărescu and Paepke (2002) consider it important as a predator on mosquito larvae (and hence a biological control for malaria) in smaller water bodies.

Conservation

Holčík and Oláh (1992) report the loss of this species from the Anzali Mordab, where it was once abundant, through a change in the environment to fresh water from brackish, siltation, oxygen depletion and loss of spawning grounds. Keivany (1966) considers it to be rare on the southern Caspian Sea coast while Kiabi et al. (1999) consider this species to be of least concern in the south Caspian Sea basin according to IUCN criteria. Criteria include medium numbers, widespread range (75% 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 further investigation.

Sources

Descriptions of breeding and some meristic characters are taken from Münzing (1969) and Ziuganov and Gomeluk (1985).

Iranian material: CMNFI 1970-0552, 1, 16.0 mm standard length, Gilan, Sowsar Roga (37º27'N, 49º30'E); CMNFI 1970-0554, 12, 17.5-22.0 mm standard length, Gilan, Pir Bazar Roga (37º21'N, 49º33'E); CMNFI 1970-0567, 2, 17.7-21.4 mm standard length, Gilan, Pir Bazar Roga (37º21'N, 49º33'E); CMNFI 1970-0591, 2, 15.8-17.4 mm standard length, Gilan, Pir Bazar Roga (37º21'N, 49º33'E); CMNFI 1979-1215, 1, 22.3 mm standard length, Gilan, Sowsar Roga (37º27'N, 49º30'E).

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