Genus Neogobius
Il'in, 1927

This genus of gobies is found in the Black and Caspian seas where there are about 14 species, some large enough to be the object of commercial fisheries. The general Farsi name for fishes in this genus is گاوماهي (gav mahi), سگ ماهي (sag mahi) or gel-ye mahi, not repeated under each species.

Berg (1948-1949) and various papers by Pinchuk (1976, 1977, 1991) recognise Neogobius as a genus but Vasil'yeva (1989) considers that the separation of Neogobius, even as a subgenus, is doubtful and refers the species to Gobius. Simonovic (1999) briefly reviews the literature on Neogobius and its distinction from Gobius. Presence or absence of a swimbladder, egg size, and presence or absence of pelagic larvae are characters which have been used to recognise genera or subgenera but these may be phylogenetically independent (Svetovidov, 1964b). Various subgenera may be recognised within Gobius such as Gobius Linnaeus, 1758, Neogobius Il'in, 1927 (type species N. fluviatilis), Apollonia Il'in, 1927 (monotypic for N. melanostomus according to Pinchuk (1991) although Vasil'yeva (1989) and Dobrovolov et al. in Charlebois et al. (1997) add the species fluviatilis on the basis of osteology and electrophoretic studies; and then later she (Vasil'eva, 1996a) places both these species in the subgenus Neogobius, again on osteological grounds), Ponticola Il'in, 1927 including such species as ratan (type species), and Eichwaldia for caspius (type species)(Eichwaldia is preoccupied by Eichwaldia Billings 1858 in fossil brachiopods, replaced by and objective synonym of Eichwaldiella Whitley, 1930). For the moment I retain most species in Neogobius as their relationships and species content have not yet been fully resolved. Miller and Vasil'eva in Miller (2003 - Vasil'eva's assignments) give the following subgenera, with definitions (these subgenera may eventually be elevated to genus once a thorough analysis is complete (see below); note assignments conflict in part with the above:- Neogobius (with one species, caspius), Apollonia (fluviatilis and melanostomus), Babka (gymnotrachelus, not in the Caspian Sea), Ponticola (the remainder - including species not in the Caspian Sea). Miller in Miller (2004) place Neogobius bathybius in the genus Chasar and this is followed here. Neilsen and Stepien (2006) and Stepien and Tumeo (2006) used mtDNA cytochrome b sequence data and consider Apollonia (N. melanostomus and N. fluviatilis) to be highly divergent from all other neogobiins, Mesogobius is the sister genus of Proterorhinus and a clade of these two genera is sister to Neogobius.

Pinchuk (1991) states that many of the characters used to define genera are composed for convenience in identification rather than indicating natural relationships, i.e. the characters are simply those used in keys. Ahnelt and Holčík (1996) call the taxonomy of this genus "variable, unstable and frequently uncertain" since variation between Black and Caspian Sea populations is usually very small and since there are migrating and resident marine and freshwater populations of the same species. Miller and Vasil'eva in Miller (2003) state that the genus is paraphyletic (included species do not share an autapomorphy) but retain it for convenience on morphological grounds, a practice followed here until a cladistic revision is performed.

These gobies are characterised by having an elongate body, compressed posteriorly, mouth of moderate size, 6 first dorsal fin rays, more than 10 rays in the second dorsal fin (large number of rays in the unpaired fins according to Pinchuk (1991) compared to Gobius sensu stricto), anterior nostrils tubular but not very elongate, posterior nostrils near eye, ctenoid scales of moderate size, a scaled nape and predorsal area, cheek naked, the pelvic fin anterior membrane may have obvious lateral lobes, no barbels, upper rays of pectoral fin may be free and filament-like (Pinchuk (1991) states that they are always within the fin membrane or joined), teeth conical and in a few series, back muscles extend forward almost to the eyes, tongue not notched or only slightly notched, no swimbladder in adults, 32-35 vertebrae modally (Gobius has only 28 and Proterorhinus 30-32 (Simonovič et al. (1996)), dorsal pterygiophore formula (3)22110, anal pterygiophores before first caudal haemal spine 2 or 3, large, oligoplasmatic roe, and no pelagic larvae. Miller and Vasil'eva in Miller (2003) give details of neuromast organs as follows:- infraorbital neuromasts typically in 7 transverse rows, 4 before and 3 above hyomandibular row b, and no row a. Row 7 is made up of a few to several papillae in a row descending postero-ventrally from just in front of the anterior oculoscapular pore α. Rows 5i and 6i are separated with 5i well behind the anterior end of hyomandibular row b and with 6i reaching or falling short of row b. Dorsal supraorbital rows o are separate in the dorsal midline. Hyomandibular row z ends near pore χ. Supratemporal accessory line x¹ ending anteriorly behind pore β. Anterior oculoscapuler, posterior oculoscapular, and preopercular canals present. These have the pores σ,λ,κ,ω,α,β and ρ; θ and τ; and χ, δ and ε. Anterior oculoscapular pore ρ and posterior oculoscapular pore θ well separated.

Neogobius is distinguished from the closely related genus Mesogobius Bleeker, 1874 by having a smaller number of infraorbital transverse rows of pit organs and the transverse parietal posterior rows of pit organs are separated by a wide interspace (Pinchuk, 1991).

Simonovič et al. (1996) consider this genus of gobies to be a young one as evidenced by the distribution of species in the Caspian and Aral seas which closed recently. Simonovic (1999) concludes that Neogobius (and Proterorhinus) evolved from a common ancestor in the Dacian Basin of the eastern Paratethys (now the Black Sea) or its tributaries during the early to mid-Pliocene, as evidenced by their absence from Adriatic, Ionian and Aegean basins. Divergence probably occurred in freshwater, riverine habitats as development is direct without a pelagic larval stage as found in marine gobiids. The hypersalinity of the isolated Black Sea in the late Miocene to early Pliocene was the causal event that led to rapid speciation of Neogobius and the genus retained direct development when it returned to the Black and Caspian seas. Dillon and Stepien (2001) using mitochondrial DNA suggest that the genera Neogobius and Proterorhinus diverged about 5.2±1.0 MYA in the late Miocene/early Pliocene from a common ancestor shared with Gobius during the isolation of the Paratethys Basin from the Mediterranean Tethys Sea. This contradicts suggestions that the neogobiins diverged from Gobius during the Quaternary interglacial connections of the Black and Mediterranean seas.

Neogobius caspius
(Eichwald, 1831)

Common names

gel-ye mahi Khazari (= Caspian goby), gavmahi-ye Khazari, gavmahi-ye Daryaye-e Khazar.

[xval xulu in Azerbaijan; Khvalynskii bychok or Hyrcanian goby in Russian; Caspian goby].

Systematics

No major synonyms and no types known. Described in Latin from "Hab. in Caspio mari, in sinu Bacuensi" (in the Caspian Sea, in Baku Bay, Azerbaijan).

Key characters

This species is separated from other Caspian gobies in Iran by the rear nostril being slit-like and far from the eye margin. It has a comparatively small mouth.

Morphology

Head canals and free neuromasts on the body are typical of a Neogobius. First dorsal fin spines 5-7, usually 6, second dorsal fin with 1 spine followed by 14-17 soft rays. The first ray of the second dorsal fin may be elongated and branched at its tip and in such cases was counted as a "spine". Anal fin with 1-2 spines, usually 1, and 10-14 soft rays. Lateral series scales 57-71. Predorsal area and nape scaled, anteriorly reaching to the orbit (postorbital section of the supraorbital canal of the cephalic lateral line system). Anteriormost scales cycloid. Scales have a diamond-shaped pattern on the flank. Individual scales are squarish with the upper and lower margins straight to slightly rounded or, more rarely, each scale has an overall rounded shape. The posterior margin has two straight edges meeting at the posterior centre. The posterior margin bears ctenii. The anterior margin is wavy where the radii terminate at indentations and there is a central protuberance. Moderately numerous radii radiate anteriorly from the central point of the posterior margin, occupying the entire anterior field and spilling into the lateral fields. Circuli are fine. There is a dermal papilla on the posterior edge of the gill chamber, just under the gill cover. The gill rakers are short anteriorly and posteriorly but vary in length and the longer central rakers reach the second adjacent raker when appressed. Rakers are commonly forked or even antler-like. Dorsally the smallest rakers are difficult to distinguish from mouth cavity tubercles and only definite rakers were included in the count. The pelvic fin anterior membrane has pointed lobes. The gut is an elongate s-shape with convolutions or twists along its length. The genital papilla is bifurcated at the tip.

Meristics for Iranian specimens: first dorsal fin spines 5(1), 6(37) or 7(2); second dorsal fin soft rays 14(2), 15(10), 16(27) or 17(1); anal fin soft rays 11(2), 12(25) or 13(13); pectoral fin rays 17(6), 18(29) or 19(5); lateral series scales 60(2), 61(4), 62(6), 63(8), 64(10), 65(6), 66(1), 67(1), 68(1) or 70(1); total gill rakers 8(1), 9(3), 10(17), 11(14), 12(4) or 13(1); and total vertebrae ?.

Sexual dimorphism

Colour differences are given below.

Colour

Overall colour is a dark grey or grey-brown with a clearly contrasting white to pearly white belly and lower head surface. The back may have 7-8 dark brown or grey saddles. The flanks have 6-10 obscure dark spots. The first dorsal fin has 2-4 dark brown stripes and a black spot over the last three rays. The black spot may not be very evident and merges with the general background pigmentation. There are no clearly defined spots on the fins although the rays are brown in all but the pelvic and anal fins. The anal and pelvic fins are pearly-white. The caudal fin has a narrow whitish transparent edge. The iris has a narrow golden ring. The genital papilla is white or grey. The peritoneum is silvery-brown in preserved specimens.

Breeding males are black all over, often including the margin of the first dorsal fin. First dorsal fin ray tips may be yellowish. The belly is whitish to pale grey in front of the pelvic fins. There is a dark spot at the end of the first dorsal fin. The second dorsal fin has a narrow colourless margin but fin tips are not extended into free ends as obviously as in some Neogobius species. All fins have a fringe effect although this is not well developed in the first dorsal fin. The caudal fin has a colourless or whitish margin. The dorsal fin spot is lost temporarily after spawning.

Size

Reaches 20.2 cm.

Distribution

This species is found in the Caspian Sea and is recorded between Kultuk and Astara in Azerbaijan (Ragimov, 1965). In Iran records are from both the souwestern and southeastern Caspian Sea.

Zoogeography

Endemic to the Caspian Sea and possibly unique to the genus Neogobius should other species be assigned to what are now recognised as subgenera (see genus account above).

Habitat

Found throughout the Caspian Sea but does not enter fresh water. It is found on sand or pebble bottoms, less often on stones and rarely on soft mud. They tend to remain inshore until the winter when temperatures fall although high summer temperatures may drive them into deeper and cooler water for a short period (Pinchuk and Miller in Miller, 2003).

Age and growth

Unknown.

Food

Gut contents include polychaetes, crustaceans, small bivalve molluscs and fish. In some areas molluscs predominate, in others crustaceans.

Reproduction

Egg sizes in Iranian specimens reach 2.1 mm and fish taken on 14 May have eggs 1.9 mm in diameter suggesting a spring to summer spawning season. This species approaches coastal areas in the southern Caspian Sea at the end of March and the beginning of April, later than N. syrman and N. gorlap. Females may have up to 1007 large eggs and up to 1985 small eggs, indicating repeat spawning (Pinchuk and Miller in Miller, 2003).

Parasites and predators

Sattari (2004) records the presence of the nematode, Eustrongylides excisus, in this species. This parasite can damage muscles in commercial species and render them unsuitable for sale. This species is eaten by the Caspian seal and by sturgeons. Sattari et al. (2005) surveyed this species in the inshore area of the Caspian Sea, recording Eustrongyloides excisus and Dichelyne minutus.

Economic importance

Not reported as of economic importance in Iran, it has been caught commercially in the former Soviet Union and on rod and line. It does form part of the diet of sturgeons (Pinchuk and Miller in Miller, 2003).

Conservation

Trends in numbers of individuals of this species and threats to it have not been examined so its conservation status is unknown.

Further work

The biology of this species needs investigation.

Sources

Pinchuk and Miller in Miller (2003) is the most recent summary on this species.

Iranian material: CMNFI 2006-0022, 1,124.8 mm standard length, Gilan, south-west Caspian Sea off Astara (38°00’N, 49°30’E to 38°20’N, 50°00'E); CMNFI 2006-0027, 2, 113.4-121.1 mm standard length, Gilan, Talesh (37°48’N, 48°55’E); NMW 80605, 1, 116.1 mm standard length, Mazandaran, Now Shahr beach (36°39’N, 51°31’E); NMW 95073, 1, 92.8 mm standard length, Mazandaran, Gomishan lagoon near estuary of Gorgan River (36°59’N, 54°00’E).

Neogobius cyrius
(Kessler, 1874)

Common names

gav mahi rud-e Kura (= Kura River goby) or gavmahi-ye Rud-e Kurosh.

[Kura goby, Kura River goby].

Systematics

Studies by Vasil'eva (1995a) and Vasil'yeva and Vasil'yev (1995) indicate that gobies from the upper and middle Kura River described as Gobius cyrius Kessler, 1874 and Gobius Weidemanni Kessler, 1874, and identified by various authors as Gobius platyrostris, Gobius constructor, Gobius platyrostris cyrius, Gobius cephalarges constructor, Neogobius cephalarges constructor and Neogobius platyrostris constructor should all be referred to Neogobius cyrius.

Gobius cyrius was described from the Kura River near Borzhom, Georgia and 3 syntypes are in the Zoological Institute, St. Petersburg under ZISP 2235 (Eschmeyer et al., 1996). One of these, a male 103 mm total length and 84 mm standard length, is designated as the lectotype by Vasil'yeva and Vasil'ev (1995). Two syntypes of Gobius Weidemanni described from Transcaucasia are under ZISP 2224.

Key characters

The pelvic fin anterior membrane has large, angular lateral lobes, at least one-fifth width of rear edge and pelvic fin less than nine-tenths distance to anal fin; the posterior nostril is near the edge of the orbit; lateral series scales usually 54-76; upper lip moderately swollen, width about 0.75 to more than length lateral preorbit; and interorbital distance 0.4-0.8 eye diameter.

Morphology

The head width is much greater than its depth. The interorbital distance is not more than half the eye diameter. The top of the head and the occiput are scaled with cycloid scales. The upper lip is expanded towards the mouth corners, sometimes narrowing at the very end. The lower jaw protrudes and the angle of the jaws reaches back below the anterior half of the eye. The snout is longer than the eye diameter (1.3-14 times). The upper lip is swollen at the angle. The second dorsal fin is of equal height along its length or rising slightly higher at its middle or end. The pelvic fin has a well-developed membrane with pointed lobes and does not extend to the anal opening. The caudal peduncle is compressed, depth about 0.30-0.35 length. The caudal fin is usually rounded but may be pointed, truncated or scalloped. The predorsal area is marbled and the first dorsal fin has a distal dark band.

First dorsal fin with 6-8, usually 6, spines, second dorsal fin with 1 spine and 15-20, usually 18-19, soft rays, and anal fin with 10-16, usually 14, soft rays (but see below), pectoral fin rays 17-19, and lateral line scales 53-78. Vertebrae 33-34. The chromosome number is 2n=36-42 (Klinkhardt et al., 1995).

Meristics in Iranian material: first dorsal fin spines 6(38), second dorsal fin with 15(7), 16(28) or 17(3) soft rays, anal fin with 10(1), 11(8), 12(26) or 13(3) soft rays, and pectoral fin rays 17(3), 18(28) or 19(7). Lateral line scales 54(2), 55(5), 56(7), 57(11), 58(6), or 59(4).

Diploid chromosome number 36-42, chromosome arms 46, polymorphism seen in a pair of subteleocentric chromosomes, the number of which varies from 0 to 2.

Sexual dimorphism

Males may not become black during the breeding season (Vasil'yeva and Vasil'yev, 1995). There are various differences in morphometric characters, summarised in Vasil'eva and Vasil'ev in Miller (2003).

Colour

The body is marked by a reticulate or marbled pattern in dark fawn, by scattered light spots and by 8-10 elongate dark spots along the lateral line. The back anterior to the dorsal fin is marbled. The belly is paler than the flank. The first dorsal fin is dark, particularly in the upper part where the darkening may form a band, with a transparent margin and a conspicuous black spot anteriorly below the tip of the fin. The first dorsal, caudal and anal fins have light margins but the fins are mostly dark. The light edge is obvious in the anterior parts of the first dorsal and anal fins. Only the second dorsal fin ray tips are light. The pectoral and pelvic fins are both uniformly dark.

Size

Attains 101.3 mm standard length, 13.0 cm total length.

Distribution

This species is found in the Caspian Sea basin including the Anzali Mordab and tributary rivers (Ahnelt and Holčík, 1996) and the upper and Middle Kura River and upper Aras River of the former U.S.S.R. (Berg, 1948-1949; Vasil'eva and Vasil'ev in Miller, 2003).

Zoogeography

This species is distributed in rivers of the Caspian Sea basin in Azerbaijan and Iran while Neogobius constructor, with which it has been confused, is found in the Black Sea basin. The absence of N. cyrius from the lower Kura River could have been prevented by the prior penetration of N. gorlap (= iljini) according to Vasil'eva and Vasilev (1995).

Vasil'eva and Vasilev (1995; 1996a) consider that Sarmatian marine ancestors of modern N. cyrius and N. constructor most probably moved into fresh water during the Miocene, about 5 MYA. Mountain building in the Caucasus isolated the Kura and other rivers which once flowed to the Black Sea and their course became oriented to the Caspian Sea. Isolation of the gobies resulted in speciation.

Ahnelt and Holčík (1996) present an alternative view. They place the origin of this species in the Quaternary when fresh water from melting glaciers connected the Black and Caspian seas via the Manych Channel allowing freshwater fishes to disperse. This occurred four times during the Pleistocene, the last time about 14-12,000 years BP. A goby species was able to colonise both fresh and brackish water and particular stocks began to favour certain habitats. Those stocks which favoured headwaters evolved into N. cyrius while those which favoured lower regions and coastal areas evolved into N. gorlap (= iljini). Ahnelt and Holčík (1996) point out that there is an analogous situation in the Black Sea with N. constructor and the species N. rhodioni Vasil'yeva and Vasil'yev, 1995. Additionally all west Caucasian and Caspian riverine gobies are very similar morphologically as evidenced by the difficulty in constructing reliable keys, suggestive of recent differentiation about 11,000-9,000 years BP after the isolation of the Black and Caspian seas.

Habitat

This small goby is found only in freshwater in mountain and foothill zones in contrast to N. gorlap. It is found in shallow (3 m or less) streams with a high gradient and current speed (1.6-4.9 m/sec on the bottom) in Iran (Ahnelt and Holčík, 1996). However, Vasil'yeva and Vasil'yev (1995) record it as absent in areas of strong current in the Kura River, preferring slow current and muddy bottoms. This type of habitat is limited in Iranian rivers which are much shorter and smaller than those of the Caucasus where an extensive lowland course is found. In Iran, the stream bed is composed of stones and boulders with some pebbles in the upper reaches and pebbles and gravel in the lower reaches. Small body size is an advantage for hiding under rocks to avoid predators and to escape the rapid current.

Age and growth

Life span is up to 3 years with maturity attained in the second or third year (Vasil'eva and Vasil'ev in Miller, 2003).

Food

Vasil'eva and Vasil'ev in Miller (2003) report feeding on insect larvae and parts of plants.

Reproduction

This species may contain eggs in three size groups, the largest being 2.81 mm in diameter, indicative of batch spawning. Total fecundity reached 1060 eggs. Spawning occurs from May to August at 11-20ºC, in some localities reported only for April-May (Vasil'eva and Vasil'ev in Miller, 2003).

Parasites and predators

Unknown.

Economic importance

None reported although in Azerbaijan some are caught by anglers.

Conservation

Further field work is necessary to assess numbers and status of this species.

Further work

The biology, distribution and conservation status of this species, recently recorded from Iran, remain to be examined in detail.

Sources

Counts and data are based on Ahnelt and Holčík (1996).

Neogobius fluviatilis
(Pallas, 1814)

Common names

gavmahi-ye tireh (= dark goby), gel-ye mahi rudkhanehai (= river goby), gavmahi-ye sheni, sebele.

[gumlur xulu in Azerbaijan; Kaspiiskii bychok-pesochnik or Caspian sand goby, rastrepka (= a person with untidy hair in reference to the fringed ends of the fin rays), chernysh (= darkie), khylak (when emaciated), all in Russian; Caspian monkey goby].

Systematics

Gobius fluviatilis was originally described in part from near the mouths of rivers falling into the Black Sea and similarly the Caspian Sea. No types are known. Neogobius fluviatilis pallasi (Berg, 1916) is the subspecies of the Caspian Sea basin. Kottelat and Freyhof (2007) recognise pallasi as the Caspian Sea species and restrict fluviatilis to the Black Sea basin. The type locality is the Caspian Sea, mouths of the Ural and Volga and syntypes are in the Zoological Institute, St. Petersburg under ZISP 2195, 2204, 23137, 30729, 30736, 30738, 30919, 30920, 30924-26. 33182, 34276, 34277 (Eschmeyer's "Catalog of Fishes", downloaded 23 August 2007).

Key characters

Pelvic fin anterior membrane with rounded and shallow lateral lobes. less than one-fifth rear edge width; pelvic fin disc 0.9 to more than distance to anal fin origin; nape with ctenoid scales; first dorsal fin without large dark spot (except in juveniles); lateral series scales usually 55-70; pelvic fin membrane anterior lobes small, rounded; angle of jaw anterior to orbit; and two transverse infraorbital papillae rows below longitudinal hyomandibular row b.

Morphology

The head width (between upper origins of opercles) is about equal to head depth (at eyes). The interorbital distance is not more than 0.75 eye diameter. The top of the head and the occiput are scaled with ctenoid scales. The upper lip is expanded towards the mouth corners, sometimes narrowing at the very end. The angle of the jaws reaches back at a level between the eye and the posterior nostril. The snout is longer than the eye diameter (1.6 times). The upper lip is not swollen at the angle, and measures 0.4-0.6 lateral preorbital area (between lip and eye). The first dorsal fin is high with an acute anterior profile, the first branched ray about twice as long as the penultimate ray. The pelvic fin has small, rounded lateral lobes (< 0.2 rear edge width) and almost reaches the anal fin (0.9 distance) or extends beyond the anal fin origin. The caudal peduncle depth is 0.5-0.6 length.

First dorsal fin spines 5-7, usually 6, second dorsal fin with 1 spine followed by 11-18, usually 15-17, soft rays, anal fin with 1 spine and 11-17 soft rays, usually 13-15, and pectoral fin rays 16-19. Lateral line scales 49-69, mostly 52-65. Gill rakers 6-10. Vertebrae 31-35. The chromosome number is 2n=46, with 46 acrocentric chromosomes and 46 chromosomal arms (Grigoryan and Vasil'ev, 1993; Klinkhardt et al., 1995; Simonovic, 1999).

N. f. pallasii is distinguished by the dorsal fin spot in young fish and an average number of lateral series scales being 53 as opposed to 62 for Black Sea fish.

Sexual dimorphism

See under colour. Males become slimmer at spawning and their are morphometric differences between the sexes (Pinchuk et al. in Miller, 2003).

Colour

Overall colour is pale and sandy, in cantrast to other gobies. On the flanks and over the back there is a series of 8-9 brownish elongate spots or blotches. The belly, lower head and genital papilla are pearly white. A dark bar runs from the eye antero-ventrally to the lip. The first dorsal fin has a dark spot posteriorly, although it may be absent in some adults, and is characteristic of the subspecies pallasi (Il'in, 1956), and found in small fish in the southern Caspian, persisting in adults in the northern Caspian (Pinchuk et al. in Miller, 2003). The first dorsal fin has 1-2 rows of grey to black spots and the second dorsal fin has 1-3 rows of pale grey spots. The caudal, anal, pectoral and pelvic fins are mostly grey on the rays and immaculate.

Breeding males become black or blue-black with the dorsal, caudal and anal fins bearing a yellow-orange margin. Some fish have a very narrow colourless margin to the pectoral and pelvic fins. The second dorsal fin may only be yellowish on its first ray, the remainder being white and the caudal margin may be colourless. Rays in the second dorsal fin of breeding males become extended into free tips.

Size

Reaches 24 cm total length although in the Caspian the largest fish are 16.0 cm males (Pinchuk et al. in Miller, 2003).

Distribution

Found in the Black and Caspian seas and their basins (as far inland as Hungary) and introduced to the Aral Sea. In Iran, it is found in rivers along the Caspian coast including some upper reaches, the Aras River, the Anzali Mordab, Gorgan Bay, the southeast Caspian Sea, the southwest Caspian Sea and the south-central Caspian Sea (Shamsi et al., 1997; Abbasi et al., 1999; Kiabi et al., 1994; 1999; Abdoli, 2000).

Zoogeography

The southern Caspian Sea and its tributary rivers is inhabited by a distinct subspecies, presumably on account of isolation from populations in the Black Sea. See genus account above.

Habitat

This species is found in inshore brackish waters and enters rivers. Salinities up to 46.9‰ are tolerated in marine bays. It is found down to 25 m although depths of 0.5-10 m are preferred, shallower in spring (0.5-5.0 m), slightly deeper in summer and deeper still in fall (5-10 m)(Pinchuk et al. in Miller, 2003). It is found over sand, mud and sandy-shelly bottoms. In the Madarsoo stream of Golestan National Park, abundance ranged from 0.1 to 0.75 fish per sq m and biomass from 0.21 to 4.88 g/m² (Abdoli et al., 2002). Floods in this stream reduced the population, presumably through destruction of the substratum and its food supply. Smaller fish were caught in riffles while larger fish lived close to to the river bank in depths up to 0.5 m. Abdoli and Rahmani (2001) found this species to represent 95% of the goby catch in the Madarsoo stream, with N. melanostomus occupying the remainder.

Age and growth

Sexual maturity is attained at 2 years of age (9-12 cm for males, 8.5-10.5 cm for females) but may be as early as 1+ year (5.5 cm), particularly in the Caspian. Spawning males near Bandar-e Anzali were 12.4-15.2 cm long. Life span is 6 years but perhaps only 2+ years in the Caspian (Pinchuk et al. in Miller, 2003). Abdoli et al. (2002) found a sex ratio of 1 male to 3 females in the Madarsoo stream.

Food

Diet items include crustaceans with lesser amounts of molluscs, polychaetes, chironomids and small gobies in the north Caspian Sea. They feed most heavily in the post-spawning period in July and August (Opalatenko, 1979). The quantity of amphipods eaten increases with age while the amount of mysids decreases. Introduced species, such as crabs, the worm Nereis and the mollusc Abra, are also eaten (Kosarev and Yablonskaya, 1994). In the Madarsoo stream of Golestan National Park in Iran, Ephemeroptera and Chironomidae are the most important food items but also included Trichoptera, other aquatic and terrestrial insects, crustaceans (including freshwater crabs), arachnids, worms and snails (Abdoli and Rahmani, 1999; Abdoli and Rahmani, 2001; Abdoli et al., 2002).

Reproduction

Spawning can take place from late April to September, varying with locality. Peak spawning in the Volga River delta is in May. Spawning is recorded at 18-26ºC, 20-28‰ and 0.5-1.3 m (Pinchuk et al. in Miller, 2003). In the Madarsoo stream of Iran, spawning peaked in March with an absolute fecundity of up to 532 eggs (Abdoli et al., 2002). Fecundity reaches 1025 eggs in the southern Caspian (perhaps 12,800 eggs elsewhere) and egg diameter 2.1 mm. Yellow-amber or pale pink eggs are laid on or under stones and plants. Nests are excavated by the male under natural or artificial objects. The male defends the nest and larger males are more successful. However, the stress associated with constant defense against predators and competing males leads to extreme emaciation. Nests contain more eggs than fecundity would indicate suggesting that more than one female lays eggs in a nest (Pinchuk et al. in Miller, 2003).

Parasites and predators

Pazooki and Aghlmandi (1998) found the nematode Dichelyne minutus infecting the intestine of 6.6% of fish examined from the Tajan River in Mazandaran. Sattari (2004) records the presence of the nematode, Eustrongylides excisus, in this species. This parasite can damage muscles in commercial species and render them unsuitable for sale. Fil mahi (Huso huso), chalbash (Acipenser gueldenstaedtii) and suf (Sander lucioperca) are predators. Sattari et al. (2005) surveyed this species in the inshore area of the Caspian Sea, recording Eustrongyloides excisus and Dichelyne minutus.

Economic importance

This is the most economically important goby in the north Caspian Sea according to Berg (1948-1949). Il'in (1956) considered this an error; it is the most numerous species but commercial fishing does not occur there. Pinchuk et al. in Miller (2003) state however that it comprised 54% of the entire goby catch, although only 7.7% in southern Dagestan. It is food for sturgeons and Sander lucioperca.

Conservation

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, habitat destruction, widespread range (75% of water bodies), absent in other water bodies in Iran, and absent outside the Caspian Sea basin (as N. f. pallasi).

Further work

On of the better known gobies in Iran but could still use work on its biology.

Sources

Iranian material:

Neogobius gorlap
Il'in in Berg, 1949

Common names

mahi kafzi (= bottom-dwelling or benthic fish), gel-ye mahi sar bozorg (= bighead goby), gavmahi-ye sarbozorg, gav mahi sar gondeh, sebele, gorzak.

[Names once used for Neogobius kessleri gorlap may be applied to this new species: iribogaz xul for Azerbaijan; bychok-golovach or bighead goby in Russian; gorlap goby, Caspian bighead goby]

Systematics

The Caspian Sea basin was thought to contain the subspecies Neogobius kessleri gorlap (Il'in in Berg, 1949). Il'in (1956) and Vasil'yeva (1991) considered N. k. gorlap to be a distinct species while Berg (1948-1949) and Pinchuk (1977) on external morphological grounds considered it to be a subspecies. Karyotype data (Vasil'ev and Grigoryan, 1993) shows N. k. kessleri from the Black Sea basin to have 29 chromosomes in males and 30 in females and the number of biarmed chromosomes in 2n=29 individuals is 17 and in 2n=30 individuals it is 16. Nominal N. k. gorlap from the Caspian Sea have 2n=46 in both sexes (Vasil'yev and Vasil'yeva, 1992). Vasil'ev and Grigoryan (1993), Vasil'yev and Vasil'yeva (1992), Vasil'yeva et al. (1994) and Vasil'yeva and Vasil'yev (1994) referred the Caspian Sea basin populations to Neogobius gorlap, but indicated that this taxon required redescription and this was carried out in 1996. Vasil'eva and Vasil'ev (1996) consider that Gobius gorlap Il'in is unpublished and nonvalid, i.e. a nomen nudum (Il'in's 1941 manuscript is lost) and give the taxon the name Neogobius iljini with a type locality in the Mangyshlak region of the Caspian Sea (holotype in the Zoological Museum of Moscow State University under ZMMGU P-19726 with paratypes ZMMGU P-46453 (3 specimens); note that the Zoological Museum of Moscow University (ZMMU; their acronym) has P-19726 and P-4643 (sic)(Pavlinov and Borissenko, 2001)). Kottelat (1997) points out that Berg (1948-1949; volume 3 including gobies dated 1949) had access to and used some of Il'in's data, thus making the name gorlap available. Indeed, any of the subsequent papers by Vasil'eva and Vasil'ev and others using the name with descriptive details would have made the name available. Neogobius iljini is therefore a junior synonym of Neogobius gorlap Il'in in Berg, 1949. There is no type series for N. gorlap as it is based on Il'in's data as outlined above.

Key characters

Pelvic fin anterior membrane with angular lateral lobes, lobes about one-sixth to almost one-half width of anterior edge of membrane; pelvic fin less than nine-tenths distance to anal fin; posterior nostril near edge of orbit; anterior nape with ctenoid or cycloid scales; rear of first dorsal fin without a dark spot; lateral series scales usually 54-76; lateral lobes of pelvic fin anterior membrane large, at least one-fifth width of rear edge; upper lip not markedly swollen, width at least 0.6 lateral preorbital width (lip to orbit), if less than 0.75, then nape scales ctenoid; interorbital distance 0.8-0.9 eye diameter; and caudal peduncle depth 0.67-0.75 length.

Morphology

This species is separated from other Caspian gobies in Iran by having a completely scaled nape, scales usually cycloid on the sinciput (anteriorly on the head just behind the eyes) (70-100% cycloid; 0-30% uniseriate ctenoid in Kura River fish) and cycloid or ctenoid posteriorly over the operculum (60-100% ctenoid in Kura River fish, 0-50% ctenoid in others); scales on the middle of the upper third of the operculum usually cycloid (70-100%); head depth at the eyes is slightly less or about equal to head width between the upper origins of the opercles; a large mouth with the jaw angle below the anterior part of the eye; the snout is much longer than the eye, 1.5-1.6 times; upper lip not expanded, or only slightly, less than lateral preorbital area (between lip and eye); interorbital distance less than 0.85 eye diameter; first dorsal fin not higher than second dorsal fin; moderately large, angular or pointed rather than rounded lateral lobes to the anterior pelvic membrane (rather small and obtuse lobes according to Ahnelt and Holčík (1996)), the membrane is 0.2-0.3 the width of the rear edge as opposed to not more than one-sixth; pelvic disc length is about 0.8 length of pelvic origin to anus length; scales in lateral series 53-79; caudal peduncle depth is 0.6-0.75 its length; the posterior nostril is close to the eye margin; and overall colour is yellowish and marbled.

The head in fish from the Kura River and possibly Iran have a rather subcylindrical shape (43.8-60.0%), while marine and north and middle Caspian Sea basin fish have a depressed and wide head, the width being markedly greater than the depth. The caudal fin is rounded, oval, or rarely elongated.

First dorsal fin spines 5-7, usually 6, second dorsal fin with 1 spine followed by 15-20, usually 18, soft rays, anal fin with 1 spine and 11-16, usually 13-15 (but see below), soft rays, pectoral fin rays 17-22, and pelvic fin rays 8-9. Marine specimens and those from the lower Volga River and Yashan Lake in the Uzboi River system of Turkmenistan have less than 15 anal fin branched rays while freshwater populations (in the Kura River at least, perhaps Iran) have 30-60% of all fish with 15 rays. Scale counts in the southern Caspian Sea are less (53-74) on average than for other populations (61-79) (Vasil'eva and Vasil'ev, 1996). Gill rakers 5-8. Vertebrae 33-35. The chromosome number for N. gorlap is distinctive with 2n=46 with 46 chromosomal arms (Vasil'ev and Grigoryan, 1993; Esmaily and Kalbassi, 2008).

Meristic values for Iranian specimens are: first dorsal fin spines 6(16), second dorsal fin soft rays 16(4), 17(11) or 18(1), anal fin soft rays 12(13) or 13(3), pectoral fin rays 18(8) or 19(8) and lateral line scales 63(5), 64(2), 65(2), 66(2), 67(2) or 68(2).

Sexual dimorphism

Abdurakhmanov (1962) reports on fish from Azerbaijan that head width, predorsal distance, second dorsal fin and anal fin bases and length of third branched anal fin ray are all greater in males while pelvic fin length and eye diameter are greater in females. In sea populations, females are larger than males.

Colour

A strongly yellow to reddish-yellow coloration distinguishes this species (Berg, 1948-1949; Vasil'eva and Vasil'ev, 1996) although Gavlena (1977) describes Volgograd Reservoir specimens as brown and others agree fish may be dark brown to dark grey or greenish. There are 4-8 elongated dark brown spots along the mid-flank in freshwater specimens, the last forming a horizontal "T" with the cross-bar on the caudal fin base. The flanks are usually marbled dark brown with light brown and yellowish strips, sometimes in a cellular design. There are light spots, darkly rimmed, along the sides of the head and near the pectoral fin bases, the latter also being likened to a network, reticulate pattern or cellular design. Cheeks with reticulate or roundish-cellular design. Short, longitudinal stripes often present below the eyes. The belly is light grey or light yellowish.

Dorsal, caudal and pectoral fins yellowish to light brownish. Second dorsal fin branched ray tips white. The fins typically have rows of small dark, orange-grey spots, although the pelvic fin has only a little dark grey or yellowish pigment with some brownish strips or many minute spots. The first dorsal fin lacks a large spot but has 3-4 series of spots; the second dorsal fin has 2-6, usually 3-4, series of spots; the anal fin is yellow to grey with occasional spots; the pectoral fin has 8-10 series of spots; and the caudal fin has 7-8 series of spots. The ends of the second dorsal fin branched rays are white. The anal fin has a light border as does the pelvic disc, although the latter sometimes has a black centre. The caudal fin has many minute spots. The genital papilla is dark grey. Young fish may appear spotted but have a more reticulate pattern on the flank than N. ratan and are generally darker.

The dorsal fins in breeding males have a wide yellowish or white margin and the second dorsal fin rays have free tips. The margin is rusty in a female. The head can be a dark bluish-grey and the flanks are dark with some paler markings. Fin membranes become dark.

Size

Reaches 22.5 cm. Freshwater populations have fish much smaller than those in the sea (Vasil'eva and Vasil'ev in Miller, 2003).

Distribution

Found in the inshore Caspian Sea and tributary rivers. It is reported from between Kultuk and Astara in Azerbaijan (Ragimov, 1965) and from the Uzboi Lakes in Turkmenistan. In Iran, it is reported from a wide range of rivers from Astara to the Gorgan and probably the Atrak, the Aras River, the Anzali Mordab and Gorgan Bay, the southeast Caspian Sea, southwest Caspian Sea and south-central Caspian Sea (Holčík and Oláh, 1992; Ahnelt and Holčík, 1996; Abbasi et al., 1999; Kiabi et al., 1999).

Zoogeography

This species is thought to have evolved from populations which settled in the lower reaches of rivers and in coastal areas while those populations which penetrated headwaters evolved into N. cyrius (q.v.) (Ahnelt and Holčík, 1996). See also genus account above.

Habitat

This species is found in fresh and brackish waters in rivers and lagoons and in inshore waters of the Caspian Sea. In the sea, it is found down to 10 m, rarely to 20 m, on rocky and dense sand bottoms. It moves inshore in the sea for spawning and retreats to deeper water (6-12 m) to overwinter (Vasil'eva and Vasil'ev in Miller, 2003). It may be found among reeds. It can live at river sites with a current velocity at 4.5 m/sec on the bottom (Holčík and Oláh, 1992). This species is allopatrically distributed with Neogobius cyrius (q.v.). Ahnelt and Holčík (1996) rate this species as a eurytope, inhabiting both fresh and brackish waters, slow and rapid currents, and clay and pebble and gravel bottoms.

Age and growth

Brackish water populations grow larger than freshwater ones (Ahnelt and Holčík, 1996). Males attain 3 years, females 2 years, and males grow faster than females. Maturity is reached at 1+ for most females and 2+ years for males (Vasil'eva and Vasil'ev in Miller, 2003).

Food

The principal food in the sea is fishes, mostly gobies and Atherina, but also includes crustaceans. Benthic food means this species competes with commercial fishes. In fresh water, fishes eaten include Balitoridae and the cyprinid Alburnoides bipunctatus, as well as crustaceans such as gammarids (e.g. Dikerogammarus haemobaphes), gobies such as its own species and N. melanostomus, insects and clams (Gavlena, 1977).

Reproduction

Spawning takes place in June in the Volgograd Reservoir and each female may contain up to 576 eggs (Gavlena, 1977). In the Caspian Sea, fish have as many as 3506 large eggs and 3399 smaller ones. Spawning takes place on rock and shingle bottoms with eggs laid on various objects. The males of this species are nest guarders. Spawning in the southern Caspian is in April and May with two batches of eggs deposited. In the lower Volga River, spawning is from the end of April to July (Vavsil'eva and Vasil'ev in Miller, 2003).

Parasites and predators

The Caspian seal, Pusa caspica, is a predator on this species (Krylov, 1984). Pazooki and Aghlmandi (1998) found the nematode Dichelyne minutus infecting the intestine of 100% of fish examined from the south Caspian Sea in Iran. Sattari (2004) records the presence of the nematode, Eustrongylides excisus, in this species. This parasite can damage muscles in commercial species and render them unsuitable for sale. Sattari et al. (2005) surveyed this species in the inshore area of the Caspian Sea, recording Eustrongyloides excisus and Dichelyne minutus.

Economic importance

None in Iran although it has formed a small part of the goby catches in the former Soviet Union. It is also caught by anglers (Vasil'eva and Vasil'ev in Miller, 2003).

Conservation

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 biology of this specie sin Iran needs work.

Sources

Meristics and colour description based in part on Gavlena (1977) describing fish from the Volgograd Reservoir, identified as N. kessleri. Counts and data for Iranian fish are based on Ahnelt and Holčík (1996).

Iranian material:

Neogobius gymnotrachelus
(Kessler, 1857)

Caspian Sea basin but no Iranian record although Kottelat and Freyhof (2007) map it from the Iranian shore. Gobius macropus De Filippi, 1863 described from Lake Palestrom near Poti, Georgia is a synonym. Neogobius gymnotrachelus macrophthalmus (Kessler, 1877) described from the middle and south Caspian Sea is the subspecies of the Caspian Sea (Berg, 1948-1949).

Neogobius melanostomus
(Pallas, 1814)

Common names

gavmahi-ye gerd (= round goby), gel-ye mahi gerd (= round goby), gavmahi domgerd, gavmahi-e-domguerd, sebele.

[xazar kirda xulu in Azerbaijan; Kaspiiskii bychok-kruglyak or Caspian round goby in Russian; black spotted goby].

Systematics

Gobius melanostomus was originally described from Sevastopol and Balaklava, Ukraine, on the Black Sea. No types known.

Gobius affinis Eichwald, 1831 described in Latin from "Hab. in Caspii maris sinu bacuensi, balchanensi" (Baku and Balkhan bays in the Caspian Sea, no types known) and Gobius sulcatus Eichwald, 1831 described in Latin from "Hab. in Caspii maris sinu balchanensi" (Balkhan Bay in the Caspian Sea, no types known), are synonyms. The Caspian Sea population was referred to Neogobius melanostomus affinis (Eichwald, 1831) but subspecies are no longer recognised (Il'in, 1956; Pinchuk, 1976).

Key characters

Pelvic fin anterior membrane with rounded and shallow lateral lobes; lobes not more than one-sixth width of anterior edge of membrane, or lacking entirely; nape scaled and at least anterior nape scales cycloid; first dorsal fin with large dark spot at rear; and lateral series scales usually 49-55.

Morphology

This species is separated from other Caspian gobies in Iran by having a small mouth, rounded, shallow, poorly-expressed lobes to the pelvic anterior membrane, scales in lateral series 41-59 (usually 47-55), generally at the low end of this range, mid- and anterior nape scales are cycloid as are most of those on the gill cover, throat, pectoral in bases and part of the abdomen, the pelvic disc is 0.6-0.8 pelvic base to anal fin length, the jaw angle is below the level of the anterior part of the eye, the posterior nostril is close to the eye margin, and the first dorsal fin has an obvious dark spot posteriorly.

First dorsal fin spines 5-8, usually 6, second dorsal fin with 1 spine and 11-18 soft rays, anal fin with 1 spine and 9-14 soft rays, and pectoral fin with 16-20 branched rays. Scales appear as diamond-shaped on the flank since the posterior margin has two straight edges coming to a central point. However scales can be quite rounded even adjacent to those forming a diamond pattern. The posterior margin bears ctenii. Dorsal and ventral margins are rounded and the anterior margin is indented above and below a central protuberance. Radii radiate anteriorly from the centre of the posterior margin. Circuli are fine. Gill rakers 9-13, presumably on lower arch only, see below. Gill rakers may reach the second adjacent raker when appressed and although usually regular can be branched and variable in size along the arch. Vertebrae 31-34.

Head depth at the eyes is 0.9-1.2 head width between the upper origins of the opercles. The interorbital width is 0.8 to slightly less than eye diameter. The snout is longer than the eye, 1.1-1.4 times. The upper lip narrow slightly rearward and is about half the lateral preorbital area (between lip and eye). Caudal peduncle depth is two-thirds its length. The tongue is truncate or slightly notched. The posterior teeth on the dentary bone are smaller than the anterior teeth and all are blunt. Pharyngeal teeth are molariform, adapted to crushing molluscs. The anal papilla is bifurcated at the tip. The gut is short and roughly s-shaped with some convolutions, particularly on the posterior section.

The chromosome number for "N. m. affinis" is 2n=46 with 46 chromosomal arms (Ráb, 1985; Vasil'ev and Grigoryan, 1993; Simonovic, 1999).

Meristics for Iranian fish:- first dorsal fin spines 5(6) or 6(34); second dorsal fin soft rays 12(1), 13(2), 14(18), 15(18) or 16(1); anal fin soft rays 10(3), 11(17), 12(19) or 13(1); total pectoral fin rays 17(11), 18(28) or 19(1); lateral series scales 48(1), 49(3), 50(8), 51(4), 52(8), 53(4), 54(5), 55(4), 56(2) or 57(1); total gill rakers 11(5), 12(15), 13(11), 14(7) or 15(2); total vertebrae ?.

Sexual dimorphism

Females are smaller than the male. Mature males have larger dorsal, pectoral and anal fins, swollen cheeks, and colour is different (see below).

Colour

Overall colour is yellowish-grey or brownish-grey (fawn) with 8-9 large, dark brown, blue-grey to black flank blotches. There are 4 saddles across the back. The first dorsal fin has a black blotch posteriorly over the last two rays (and sometimes on the interradial membrane between rays 4 and 5), and the blotch or spot may have a white border in juveniles. The spot can be absent as reported by Jude (1997) for fish introduced to the North American Lake Erie. The sides of the head have oblique, curved bands or a reticulate pattern of a rusty to gingery tint on a bluish-grey background. The pattern is darker on the opercle and snout. The first dorsal fin may be tinged green and has 3 rusty-brown bands and a narrow margin may be a rusty or yellowish colour. The second dorsal and caudal fins may have a light margin even in non-spawning individuals. The second dorsal fin has 3-4 rows of small rusty spots. The caudal fin also bears rusty spots anteriorly but not in very definite rows. The anal fin is grey to dark brown. The pectoral fin lacks spots and is almost colourless but may be tinged with yellow. The pelvic disc is grey with a rusty colour in the centre. The genital papilla is grey or unpigmented. The iris is yellow to orange. The peritoneum is a silvery brown.

Colour varies with habitat. In bays with algal growth fish are darker, blue-grey tints are lost, there are more yellowish-brown colours and there is an increase in number and size of dark-brown spots. Others may have an olive-green tint.

When spawning, males are charcoal black overall, sometimes with a bluish tint, and with indistinct yellow spots. The dorsal, caudal and anal fins are white-edged or yellow, although the first dorsal margin can be black and there may be practically no margin to the anal fin. The black spot on the first dorsal fin can still be seen against the light. There are no free tips to fin rays according to literature reports but Iranian specimens have all fin tips separated to form a fringe.

The young are a slate grey overall with a mottled and blotched flank. The mid-flank blotches may form a series of about 6. There is a spot at the upper base of the pectoral fin. The dorsal fin spot is centred on the membrane between the last two rays but spills over onto the adjacent membranes, particularly the posterior one. Fins have pigment on the rays and membranes with no clear pattern. The dorsal fins are darker than the anal which is darker than the pectoral or pelvic. There is a bar from the lower eye margin to the upper lip just anterior to the mouth corner.

Size

Reaches 29.0 cm total length. Freshwater fish are smaller than marine ones.

Distribution

Found from the Aegean to the Black and Caspian seas. Introduced to the Aral Sea in the 1950s but increasing salinity in the 1980s eliminated the population. Now in the Baltic Sea via rivers and canals or in ship ballast. Also present by introduction in the Great Lakes of North America where first reported in 1990, apparently from several sources (Brown and Stepien, 2006).

Reported from a wide range of rivers along the Caspian coast of Iran, the Anzali Mordab, Gorgan Bay, the southeast Caspian Sea, southwest Caspian Sea and south-central Caspian Sea (Holčík and Oláh, 1992; Abbasi et al., 1999; Kiabi et al., 1999; Abdoli, 2000; Jolodar and Abdoli, 2004).

Zoogeography

See genus account above.

Habitat

This species is found in inshore waters at depths to about 20 m, sometimes to 70 m or even 200 m in deeper sea areas in winter, on rock, gravel, shell, sand or silt bottoms. Aquarium specimens are seen to hide in crevices and under rocks. In the Caspian Sea, it may be found among eelgrass, Zostera. It also enters rivers. Larvae live near the bottom. The species prefers littoral areas where wave action keeps oxygen levels high and decaying material is reduced. It leads a sedentary life (Moskal'kova, 1996). It may be found from fresh waters to salinities of 40.5‰ from -1 to 32°C, and respiring through the skin can tolerate low oxygen conditions from 0.3-0.9 ml/l (Moskal'kova, 1996; Jude, 1997).

In the North American Great Lakes basin, where it is an exotic, this species prefers rocky habitats and is more active during the day than the night. The mean density in one river was approximately 7 gobies/sq m and can reach as high as 90 gobies/sq m since they aggregate. This goby has a high site fidelity in mark-recapture studies (Ray, 1997; Ray and Corkum, 1997a).

The gobies can tolerate a flow of 0.34 m/s for 3-4 minutes but at higher levels they retreat to the bottom and brace themselves against the current using the pectoral fins.

The onshore spawning migration in the southern Caspian Sea occurs in spring, later than N. syrman and N. gorlap. A spawning area is chosen on the basis of stones being present rather than depth. Larger males approach the shore first. There is an offshore movement as winter begins and in the hottest part of summer.

Age and growth

Maturity is attained in the second year by females and in the third year by males but may be as early as 1 year. Life span can exceed 5 years for females. Males die after spawning. Faster growth results in a shorter life span. At the end of the first year of life they can reach 5.5-6.0 cm (Moskal'kova, 1996). In North America, populations of this exotic are dominated by age one fish (MacInnis and Corkum, 1997a). Growth is slower in North America and maximum size is less than in its native habitat, probably because temperatures are lower than in Europe (Jude, 1997).

Food

Molluscs predominate with significant amounts of crustaceans in the north Caspian Sea but this can vary annually with crustaceans becoming predominant. They feed most heavily in the post-spawning period in July and August (Opalatenko, 1979). Other important foods are bivalves, such as zebra mussels, snails, polychaetes, chironomids, other aquatic insects, goby eggs and small fishes. Attached clams and mussels are bitten off the substrate by the large jaw teeth and crushed by the pharyngeal teeth (Moskal'ova, 1996). Molluscivory is also documented for Danube River populations (Simonovič et al., 2001) and for Baltic Sea populations (Skora and Rzeznik, 2001) and molluscs appear to be the preferred diet wherever this species is found. An exception may be the southern Caspian Sea where one study found crustaceans to predominate (Pinchuk et al. in Miller, 2003).

In the Caspian Sea, introduced species, such as crabs, the worm Nereis diversicolor and the mollusc Abra ovata, are also eaten (Kosarev and Yablonskaya, 1994). Iranian specimens contain plant fragments, mollusc shells, shrimps, fish remains, aquatic insects and polychaetes.

In North America, immature round gobies are the most successful predators on round goby eggs. Round gobies are said to be aggressive and will take a baited hook. However this goby may need to be stationary to detect prey. Nocturnal feeding occurs. The blunt teeth are indicative of a primarily mollusc diet.

Experimental studies in North America have shown this species to prefer individual and clumped zebra mussels to other foods such as sphaeriid clams. Feeding rates vary between 36 and 47 mussels (4.5-12.5 mm long) per day for fish 6-10 cm long, over 100 mussels per day when the mussels are smaller than 4 mm (Ghedotti et al., 1995). Mussels can remain in the mouth and pharynx for less than one hour to over 12 hours; shells are then split and ejected. However some are crushed and passed through the digestive tract. In the upper Detroit River, Canada, round gobies eat zebra mussels (58%), snails (6%) and other invertebrates (36%) such as aquatic insects, softshelled crayfish and zooplankton. In laboratory studies, round gobies ate an average of 1 g of mussels in 24 hours, smaller mussels being preferred (Ray and Corkum, 1997b). However, field studies in Lake Michigan show that round gobies are unlikely to remove zebra mussels (also a pest in North America) from a habitat (Djuricich and Janssen, 2001). These gobies are also predators on lake trout eggs under laboratory conditions in North America (Chotkowski and Marsden, 1999). They are also reported to eat sturgeon eggs in North America.

Reproduction

There is a movement inshore to waters about 0.2-1.5 m deep for spawning, males preceding females. Spawning takes place at the end of April to September in near shore areas of the north Caspian Sea and over a similar period in the Baltic Sea. Iranian specimens have well-developed testes on 10 April and spawning may occur earlier than in the North Caspian. There may be repeat spawning, up to 6 times every 18-20 days, as indicated by captive specimens. Peak spawning occurs at 15°C (range 10-30°C). Eggs are attached to or under rocks, in cavities, under logs or in such objects as cans and are aggressively guarded by the male. Early maturity, a very long spawning season and aggressive defense contribute to high egg, larvae and fry survival. The male prepares the nest site with a secretion from a cement gland which is coated over the site. As the female lays each egg, it is glued to the underside of the nest cavity roof in single layer rows. Egg clutches can be transported on the hulls of ships (Ahnelt et al., 1998). Fecundity reaches 6,177 eggs. Eggs are pale yellow, orange or pink, with red pigmentation. the eggs are ovoid with a sharp apex and measure 3.9 by 2.2 mm. Details of development are given by Moskal'kova (1996).

In North America, the species has been shown to be a multiple spawner with an extended reproductive season and male guarding of eggs (MacInnes, 1997). Here maturity occurs as early as year one and 43 mm standard length, a year earlier than in their natural habitat. Spawning extends from May to early August. Mean fecundity is 198 eggs. Each nest is utilised by large numbers of females since as many as an estimated 9462 eggs were found in each artificial nest site (MacInnis and Corkum, 1997b). Such a nest site can lose 50-70% of the eggs to predators while smaller clutches lose few eggs.

Jude (1997) notes that in North America some males do not defend a nest, the reason being unknown. This may well be due to such factors as availability of suitable spawning sites, large size or aggressiveness. He reports that after reaching a large size, males spawn once and then die, although females spawn up to six times through spring and summer, about every 20 days. Elsewhere males guard the nest from predators and fan the eggs to oxygenate them and to reduce siltation and fungal infection. Males will eat infected and unfertilised eggs. Males defend the nest by flaring the gills, spitting sand, darting at nearby intruders, biting, and growling for 1.0-1.5 seconds loud enough to be heard 10 m away. Nest sites in North America may be as deep as 7 m (Corkum and Wickett, 1998).

Males make several sounds including one attracting females to nest sites and another to intimidate other males. Females respond to male calls by a quieter sound (Jude, 1997).

Parasites and predators

Fil mahi (Huso huso), chalbash (Acipenser gueldenstaedtii), uzun burun (Acipenser stellatus), mash mahi (Aspius aspius), ordak mahi (Esox lucius), suf (Sander lucioperca) and seals are predators. Sattari et al. (2005) surveyed this species in the inshore area of the Caspian Sea, recording Dichelyne minutus. Sattari et al. (2007) report the nematode Eustrongylides excisus for this species in Iranian waters.

Economic importance

Robins et al. (1991) list this species as important to North Americans. Importance is based on its use in aquaria, as food and because it has been introduced outside its natural range. It is caught by anglers in some parts of the Caspian Sea basin.

It is present in the North American Great Lakes and is expanding (Ray and Corkum, 2001; Clapp et al., 2001; Jude et al., 1992; Jude, 2001). It is an introduction from the ballast waters of ships from multiple sources, perhaps including the Black Sea (Dillon and Stepien, 2001). Round gobies may displace native fish, compete for food and eat their eggs and young, and are the target of major efforts to study and contain them (Arrigoni and Berg, 2001; Charlebois et al., 2001; Diers et al., 2001; French and Jude, 2001; Janssen and Jude, 2001; Kaur et al., 2001; Schreier et al., 2001; Wolfe, 2001). They may also accumulate and pass on large concentrations of such chemicals as PCBs to sport fishes in North America (Jude, 1997). An extensive literature is now available on the Great Lakes populations.

It is an important food species in the Black Sea marketed fresh and formerly canned in tomato sauce. In the Sea of Azov in 1950-1960, gobies made up the bulk in local fisheries and round gobies comprised almost 90% of a catch exceeding 90,000 t (Moskal'kova, 1996). Commercial catches in the Caspian Sea have comprised up to 88.2% of goby catches but pollution has severely depleted stocks (Pinchuk et al., 2003).

Conservation

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, habitat destruction, widespread range (75% of water bodies), absent in other water bodies in Iran, and absent outside the Caspian Sea basin (as N. m. affinis).

Further work

Biology in Iran has not been studied as well as elsewhere.

Sources

Charlebois et al. (1997) and Pinchuk et al. (2003) give general reviews of biology and are excerpted briefly above.

Iranian material:

Neogobius ratan
(Nordmann, 1840)

Common names

gavmahi-ye ratan, gel-ye mahi ratan.

[Kaspiiskii bychok-rotan or Caspian ratan or rotan goby in Russian].

Systematics

Gobius ratan was originally described from Odessa on the Black Sea.

Gobius Bogdanowi Kessler, 1874 described from the Caspian Sea at Makhachkala (Petrovsk) is a synonym (the male of N. ratan goebeli according to Il'in (1956) although Pinchuk (1991) and Ragimov (1998a) consider it to be a subspecies of N. ratan). The Caspian Sea basin subspecies is usually referred to Neogobius ratan goebeli (Kessler, 1874). Pinchuk (1976) notes that fish from the Azerbaijan and Iranian coast differ from those from Dagestan and Turkmenistan, the first having fewer scales, but the number of specimens were insufficient to define taxa.

Two probable syntypes of Gobius ratan are in the Muséum national d'Histoire naturelle, Paris under MNHN A.1125 and a syntype is in the Zoologisches Museum Berlin (Museum für Naturkunde, Universität Humboldt, Berlin) under ZMB 2098 (Bauchot et al., 1991).

Gobius Goebelii Kessler, 1874 is described from Baku, Azerbaijan with a syntype in the Naturhistorisches Museum Wien under NMW 33910 and others possibly in the Zoological Institute, St. Petersburg (ZISP 2229-30) (Eschmeyer et al., 1996; Pinchuk et al., 2003). Neogobius ratan goebeli is recognised by Ragimov (1998a) as a subspecies in the southwestern Caspian Sea.

Two syntypes of Gobius Bogdanowi are possibly in the Zoological Institute, St. Petersburg (ZISP 10902) (Eschmeyer et al., 1996; Pinchuk et al., 2003).

Key characters

Pelvic fin anterior membrane with angular lateral lobes, not more than one-fifth width of rear edge; pelvic fin almost reaches the anal fin (0.9 distance) or extends beyond the anal fin origin; posterior nostril near edge of orbit; anterior nape with cycloid scales; rear of first dorsal fin without a dark spot; lateral series scales usually 49-54; and upper lip width 0.4-0.67 lateral preorbital width (lip to orbit).

Morphology

Pelvic fin anterior membrane with angular lateral lobes, rather than rounded; lobes small, not more than 0.2 width of rear edge; posterior nostril near edge of orbit; angle of jaw below pupil of eye; upper lip slightly swollen posteriorly, 0.5-0.67 lateral preorbital area (between lip and eye); first dorsal fin with sub-horizontal upper profile; rear of first dorsal fin without a dark spot; head depth at eyes slightly less to somewhat greater than width between upper origins of opercles; snout length about 0.9-1.2 orbit; lateral series scales usually 52-61; interorbital width 0.4-0.6 eye diameter; nape scales cycloid; pelvic fin almost reaches the anal fin (0.9 distance) or extends beyond the anal fin origin; the caudal peduncle depth almost equals its length, the posterior nostril is close to the eye margin, and colour dark brown with few spots (spawning males black). The two subspecies listed above are distinguished partly by scale counts, 63-66 in bogdanowi and 63 or less in goebeli.

First dorsal fin with 5-7, usually 6, spines, second dorsal fin with 1 spine and 15-19 soft rays, anal fin with 1 spine and 11-15 soft rays, and pectoral rays 17-21. Range in lateral series scales 49-70. Vertebrae 32-34.

Sexual dimorphism

Male colouration is distinctive and they have a higher dorsal fin.

Colour

Overall colour is dark brown with a few, discrete, rounded pale spots and, along the mid-flank, a series of small horizontal bars. Pale saddles cross the back. The first dorsal fin has a yellow or intense orange margin above a black bar (white in preserved fish). This fin also has a dark blotch, often with a bluish tint, on the first and second and second and third interradial membranes, and sometime son the third and fourth interradial membrane. The second dorsal fin is greyish with 3-4 rows of brown spots proximally, and it may have a pale margin. The pectoral and caudal fins have rows of rusty-brown spots proximally. The pelvic fin disc and the anal fin are grey with a broad pale margin. The belly is grey. Breeding males become black with a bluish tint.

Size

Reaches 23 cm.

Distribution

Found in the Black and Caspian seas including Iranian waters of the latter.

Zoogeography

See genus account above.

Habitat

This species lives in inshore waters over rocks, gravel and stones, although a spawning male was caught over silt near the Kura River, and a female was caught at 11 m at Krasnovodsk (Pinchuk et al. in Miller, 2003). It rarely enters fresh waters, at least in the Caspian.

Age and growth

Sexual maturity is attained at 2 years.

Food

The main food items are crustaceans, with smaller quantities of worms, molluscs and fish.

Reproduction

Spawning takes place from the end of March to the end of May, with a single repeat spawning. Eggs are deposited on and between stones. Females contain 22-360 ripened eggs (Pinchuk et al. in Miller, 2003).

Parasites and predators

None reported from Iran.

Economic importance

None as it is disliked by commercial and sport fishermen and is not common in the Caspian Sea (Pinchuk et al. in Miller, 2003).

Conservation

No data for Iran. Endangered in Turkey (Fricke et al., 2007).

Further work

The biology of this species in Iranian waters requires study.

Sources

Iranian material:

Neogobius syrman
(Nordmann, 1840)

Common names

None (other than general names listed under genus above).

[shirman in the Ukraine, syrman goby, Kaspiiskii shirman or Caspian syrman goby]

Systematics

Gobius syrman is described from Odessa, Dniester estuary, in the former U.S.S.R., now Ukraine). Gobius Trautvetteri Kessler, 1859 described from the lower Bug and Dniester rivers in the former U.S.S.R. and Gobius eurystomus Kessler, 1877 described from the southern Caspian Sea are synonyms. Berg (1948-1949) has eurystomus as a valid subspecies of N. syrman but this is not accepted now (Reshetnikov et al., 1997). Presumed syntypes of G. syrman are in the Natural History Museum, London (BM(NH) 1872.5.30:35, 105.0 mm standard length), Muséum national d'Histoire naturelle, Paris (MNHN A. 1126) and in the Naturhistorisches Museum Wien (MNMW 30099. Syntypes of G. eurystomus are under BM(NH) 1897.7.5.8-9 (2, 73.6-88.6 mm standard length), in the Zoological Institute, St. Petersburg (ZISP 10904-05), and perhaps NMW 29176. (Pinchuk et al. in Miller, 2003).

Key characters

Three transverse suborbital neuromasts rows occur ventral to the longitudinal suborbital row b while all other Neogobius have typically two rows. Additionally, pelvic fin anterior membrane with rounded and shallow lateral lobes, lobes not more than one-sixth width of anterior edge of membrane, or lacking entirely; pelvic fin disc two-thirds distance to anal fin origin; nape with ctenoid scales; first dorsal fin without large dark spot; lateral series scales usually 55-70; and angle of jaw below pupil of eye.

Morphology

First dorsal fin with 5-7, usually 6, spines, second dorsal fin with 1 spine and 15-19, usually16-18 soft rays, anal fin with 1 spine and 10-15, usually 12-14, soft rays, and pectoral rays 17-21. Range in lateral series scales 56-79. Vertebrae 34-35. Pelvic fin anterior membrane with very shallow, rounded lateral lobes. Posterior nostril near edge of orbit. Angle of jaw below anterior part of pupil, upper lip with uniform width, about half lateral preorbital area (between lip and eye). First dorsal fin relatively high, with rounded upper profile, without an upper anterior dark blotch. Second dorsal fin highest in middle. Head depth at eyes 1.1-1.2 width between upper origins of opercles. Interorbital width less than or equal to eye diameter. Snout length 1.3-1.4 orbit. Lateral series scales usually 59-67. Nape and predorsal area scaled completely. Breast, base of pectoral fin and upper part of opercle scaled, cycloid scales on ventral part of abdomen, opercle and anterior part of nape. Pelvic fin about two-thirds distance to anal fin origin. Caudal peduncle depth about half length. Posterior nostril close to the eye margin. The head canals and the free neuromasts on the body are typically arranged for a neogobiine. Three transverse suborbital neuromasts rows occur ventral to the longitudinal suborbital row b.

Sexual dimorphism

Males may have a more intensely dark distal band and body spots during spawning. Male median fin rays are slightly elongated during spawning. Females are usually smaller than males.

Colour

Overall colour pale grey, brownish-grey or more rarely yellowish-brown (perhaps fish parasitised with the strigeid nematode Neascus), with pale saddles across the back extending onto the flank and sometimes meeting dark blotches along the mid-flank. The body has large grey-brown markings arranged in a chequer-like pattern. The head has brown markings laterally and a dark band antero-ventrally from the eye to the upper lip. The first dorsal fin has a pale yellowish margin set off by a dark stripe above two brown stripes proximally. The second dorsal fin bands are less distinct and the anal fin has an indistinct, bluish band and a white margin. The pectoral fins are yellowish and the pelvic disc is pale. Belly pale. Males do not become dark during spawning (Pinchuk et al. in Miller, 2003).

Size

Attains 29.2 cm.

Distribution

Black and Caspian Sea basins including the Imeni Kirova or Kyzylagach Bay near the northwestern Iranian border (Kuliev, 1989) and between Kultuk and Astara in Azerbaijan (Ragimov, 1965) and recently recorded from Iran (Ahnelt et al., 2007). Reported from the Anzali Mordab and Gomishan Lagoon (Jolodar and Abdoli, 2004). Introduced to the Aral Sea.

Zoogeography

See genus account above.

Habitat

This goby is found principally in the sea, with one report from fresh water in the Caspian Sea basin (Emba River, Kazakhstan). It is unusual in being found on mud and silt bottoms and can tolerate low oxygen concentrations (to 20% saturation). It is rare offshore at 6-20 m in the Caspian Sea. It is found in the Caspian at 1-10 m, retreating in summer to slightly deeper water, reappearing as autumn cooling occurs, and then spending the winter at 30-50 m. It approaches shores earlier than other gobies for spawning, as early as the latter half of February for males with females in the second half of March (Pinchuk et al. in Miller, 2003).

Age and growth

Maximum age may be 6 years although most fish probably live only half this time. Maturity may be attained shortly before age 1 year and by 2 years for most fish.

Food

Fish, crustaceans and Nereis worms are the main diet items in Caspian Sea fish examined. Fish included Knipowitschia and fry of Neogobius fluviatilis and N. melanostomus as well as clupeids and its own species. Smaller individuals take crustaceans and larger ones favour fish (Pinchuk et al. in Miller, 2003).

Reproduction

The spawning season is from the beginning of April into May in the southern Caspian Sea. The eggs are found in two sizes, indicative of batch spawning. Up to 8474 ripe eggs are found in each female. Eggs are 4.2 by 1.9 mm and are laid under and between stones, on any available object or even muddy bottoms.

Parasites and predators

This species is eaten by Sander lucioperca and fry are eaten by sturgeons.

Economic importance

This species has been fished in former Soviet waters of the Caspian Sea because of its large size but the proportion in catches varies from 1-50%. It is important as food for commercial species.

Conservation

Only recently recorded from Iran, its conservation status in unknown.

Further work

The distribution and abundance of this species in Iranian waters needs to be surveyed as it is an important food for commercial fishes.

Sources

Pinchuk et al. in Miller (2003) is a recent summary of data on this species.

Iranian material: CMNFI 1970-0544, 1, 141.7 mm standard length, Gilan, near Bandar-e Anzali, (37°28’N, 49°27’E); CMNFI 1979-0689, 9, 87.1-124.0 mm standard length, Gilan, Safid River at Hasan Kiadeh (37°24’N, 49°58’E); CMNFI 1970-0586, 1, 100.1 mm, Mazandaran, Gorgan Mordab at Ashuradeh-ye Kuchak (36°50’N, 53°56’E); NMW 95074, 2, 100.1–130.2 mm, Mazandaran, south-east Caspian Sea near estuary of Gorgan River (36°59’N, 53°59’E); CMNFI 1979-0788, 2, 135.3–146.2 mm standard length, Mazandaran, Gorgan River (37°00’N, 54°07’E); NMW 95075, 1, 186.6 mm standard length, Mazandaran, south-east Caspian Sea, Mian Kaleh near Behshahr (36°53’N, 53°32’E).

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