The mullets or grey mullets are found world-wide in temperate to tropical coastal waters readily entering estuaries and even resident in freshwaters. There are about 17 genera and 72 species but only 3 species are native to Iran in fresh and brackish waters and a further 2 species have been successfully introduced (the latter not mapped in Berra (2001) because they are exotics). Other species are recorded as entering the rivers of southern Iran from the Persian Gulf and Sea of Oman although identification is not always certain (see Marine List). Maximum size is about 0.9 m.

This family is characterised by a compressed to subcylindrical body with a somewhat flattened head; moderate sized scales which may be cycloid but are ctenoid in most adults and extend onto the top and sides of the head; faint or no lateral line along the flank but pits or grooves on scales contain the sense organs; the eye may have an adipose or fatty eyelid forming a vertical, slit-like opening; vertebrae usually 24, rarely as high as 26; wide gill openings; gill rakers long and slender and increasing in number with growth; upper elements of the gill arch are specialised as a pharyngobranchial organ,;5-6 branchiostegal rays; a spiny and short first dorsal fin (4 spines), the second dorsal with 1 unbranched ray or spine and 6-10, usually 8, branched rays; anal fin with 2-3 spines and 8-12 branched rays; an abdominal pelvic fin with 1 spine and 5 soft rays; pelvic bones connected to the postcleithrum by a ligament; mouth transverse and small; teeth on jaws short, weak and flexible, and the lower jaw may be toothless; the stomach wall is strongly muscled (gizzard-like); and the gut is very long and coiled.

Mullets are schooling fish which feed on microscopic algae and the minute animals associated with the algae. They grub, gulp or suck (hence "mugil") bottom deposits, spitting out some of the debris and extracting nutrient from the remainder. The long gill rakers filter the food, the strong gizzard-like stomach crushes it and the long intestine (about 7 times body length) aids in digestion. Their bottom feeding leaves long patches of disturbed sediment readily visible from a distance. Eggs, larvae and young mullet are pelagic. Adults are found in large schools in coastal waters or on tidal flats. These fishes are very important economically as food eaten fresh, smoked or canned, as bait, and as cultured fish in ponds. The flesh is oily and rich but has few bones. Mugilid species in Khuzestan are thought to be the intermediate hosts of Heterophyidae flukes found in humans and carnivores (Massoud et al., 1981).

Recent studies have been carried out on culturing Mugil cephalus and Liza aurata in brackish water, in inland pools and salt and freshwater culture ponds in the northern and central parts of Iran (Emadi, 1993a; Iranian Fisheries Research and Training Organization Newsletter, 11:6, 1996; Azari Takami et al., 1997). In April 1994, 20,000 Mugil cephalus fry weighing 0.5 g were imported from Hong Kong as part of this programme (Iranian Fisheries Research and Training Organization Newsletter, 4:8, 1994). Azari Takami et al. (1997) successfully raised fry of Liza aurata and L. saliens at Bafgh-Yazd in central Iran in earthen ponds supplied with brackish well water. Fry in the 3-10 g range were cultivated for 100 days at 2200 fry/ha with pond fertilisation and with fertilisation and complementary feeding, giving 100 g and 120 g fish respectively. Experiments with different stocking densities and mixes of the two species were also carried out. Second year L. saliens reached 165 g and third year L. aurata reached 630 g and sexual maturity.

Experiments have been carried out on fishing methods for these fishes in Iran, comparing encircling gill nets with fixed gill nets and with purse seines (Annual Report 1992-93, Iranian Fisheries Research and Training Organization, Tehran; Annual Report 1993-94, Iranian Fisheries Research and Training Organization, Tehran). In 1994-1995, the total mullet catch was 4145 t, 85% of which was L. aurata. Catch per unit effort decreased by 50% over the preceding three years (Annual Report, 1994-1995, Iranian Fisheries Research and Training Organization, Tehran, p. 37, 1996).

The general name for mullets in Farsi is kefal or kafal.

Pillay (1972) gave a bibliography on mullets and Thomson (1997) reviewed the family, giving further details of anatomy than summarised here.

Genus Liza
Jordan and Swain, 1884

This genus is characterised by thin to moderately thick, terminal upper lip without papillae, the lower lip is directed forwards and is thin-edged, teeth are setiform, ciliiform or absent in the upper lip, ciliiform or absent in the lower lip, there is a symphysial knob to the lower jaw and the lower jaws meet at a 90º angle or more, the maxilla is bent down over the premaxilla and is either uniformly curved or is s-shaped, the maxilla end is visible when the mouth is closed, the anteroventral edge of the preorbital bone is serrate, weakly concave or kinked and ventrally it is broad and squarish, an adipose eyelid is present sometimes but is not well-developed being a narrow rim around the eye at all ages, the pharyngobranchial organ has two valves, pyloric caeca number 2-14, predorsal scales are unicaniculate, and the pectoral axillary scale is weak or absent. Thomson (1997) lists further characters but the genus is distinguished easily from Mugil (q.v.), the only other genus from Iran.

Liza abu
(Heckel, 1843)

Further illustrations

Liza abu, lateral view of head of above; Liza abu, dorsal view of head of above; both after Berg (1949)

Common names

بياح (biah), biah zury, zuri, kafal, shochy, do'kelki in Khuzestan (= with two sails, presumably referring to the two dorsal fins), ? derbak.

[maid, khishni, hishni, abu-khraiza, hosoon, hashsoun, abu-khraiza, or abu sukkanejn (= father of two anchors in allusion to the toothed suborbital bone according to Heckel (1843b)), all in Arabic; minghaj in Pakistan; abu mullet, freshwater mullet].

Systematics

Mugil pseudotelestes Pietschmann, 1912, described from the "Schatt el Arab bei Basra (Aschar)" (Ashar is at 30°31'N, 47°50'E), is probably a synonym (Coad, 1991b) based on the original description. Mugil hishni Misra in Hora and Misra, 1943 described from "Rivers and Hors, Iraq" (hors or hawrs are marshes) is also a synonym based on the description, an opinion concurred in with Ingham (no date) and Özdilek (2003). Thomson (1997) considers hishni to be a synonym and possibly pseudotelestes although he considers the description of this species insufficiently detailed. Mugil abu zarudnyi Berg, 1949 was described from "Ser-i-pul, 30 km from Malamir, between Deh-i-dez and Malamir, region of the Bakhtiars and Lurs, upper course of the Karun R., south-western Ian, 17 III 1904, N. Zarudnyi". Thomson (1997) considers this subspecies to be of doubtful validity given the variability of this species. Different stocks exist in the Tigris, Euphrates and Orontes rivers as evidenced by morphology (Turan et al., 2004).

Randall (1995b) places this species in the genus Chelon Rose, 1793; Thomson (1997) does not.

Material of Mugil abu, housed in the Naturhistorisches Museum Wien, is under NMW 9224-9230 (7 fish) and 67868 (2) and are syntypes. The type locality is the "Tigris bei Mossul" according to Heckel (1843b) and the catalogue lists 4 specimens.

Mugil (Liza) abu zarudnyi Berg, 1949 was described from Iranian tributaries of the Tigris River basin. The 5 syntypes of zarudnyi are in the Zoological Institute, St. Petersburg (ZISP 24336), measure 69.1-80.7 mm standard length. The date in the catalogue is 4.II.1904 (old style).

The holotype of Mugil hishni is in the Zoological Survey of India, Calcutta under ZSI F13626/1 with 1 paratype under ZSI F13627/1 (Menon and Yazdani, 1963; Eschmeyer et al., 1996).

Key characters

The high lateral scale count, long pectoral fins reaching almost level with the first dorsal fin origin when folded back (note fin tips often frayed, especially in preserved material, so not as apparent), short pectoral axillary scale, thin lips, 3 anal fin spines and 8 branched rays, relatively strong spines in the first dorsal and anal fins, and peg-like or setiform teeth (not tricuspid) in the upper jaw only, distinguish this species from other species in the genus Liza and from other mullets.

Morphology

The eye has fatty tissue covering as far as part of the iris. Lips are thin and the lower lip has a pronounced knob. Peg-like teeth are obviously present only on the upper lip, the lower lip having scattered ciliate teeth. The end of the maxilla has an s-shaped bend and its tip is exposed. The anterior edge of the denticulate preorbital is angular, bending down at the corner of the mouth. The pectoral axillary scale is weakly developed. Occasional antero-dorsal scales have double canals. Pectoral fin length is 75-78% of head length and this fin extends back to a level almost at the first dorsal fin origin. First dorsal fin spines 3-4, usually 4, second dorsal fin soft rays 5-10, usually 8 after 1-2 spines, anal fin spines 3 followed by 5-10, usually 8 soft rays, pectoral fin branched rays 13-17 and pelvic fin branched rays 5-6, usually 5. Vertebrae 21-25. Fusions and minor vertebral anomalies were described by Al-Hassan (1987) and Al-Hassan and Naama (1986b) from Iraqi fish. Lateral scales 39-53, usually 44-50. Scales are strongly ctenoid on the exposed part and the fish feels rough to touch when rubbed from tail to head. The embedded part of the scale has fine circuli. The focus is very posterior. Scale shape is rectangular with the anterior margin vertical or somewhat wavy. The anterior upper and lower corners are square or even pointed. The dorsal and ventral scale margins are straight and the posterior margin is rounded. There are a few radii (as few as 4) from the focus to the anterior margin and, where these intersect the margin, it may be slightly indented to form a wavy edge. There are 4 pyloric caeca and the gut is elongate and coiled. Gill rakers are short than the gill filaments and number 44-55. They bear teeth on the internal edge. Islam and Al-Nasiri (1978) give morphometric characters. Hoda (1978) describes the larva (as Mugil hishni) in Iraq. 2n = 50 (Balasem et al. (2000). Thomson (1997) notes that this is the most variable species in the family.

Al-Hassan (1984b) showed differences in counts of vertebrae and dorsal fin rays between fish from Basrah and the Karkheh River in Iran. Turan et al. (2004) also noted differences in morphometric data for stocks from the Orontes (= Asi), Tigris and Euphrates rivers of Turkey, attributing this to phenotypic adaptation as the stocks were genetically homogenous. Thomson (1997) notes that this is the most variable species in the family. Jawad (2004b) studied asymmetry in this species from the Shatt al Arab at Basrah and suggested pollution could be a cause. Jawad and Öktener (2007) record lordosis (axial spinal curvature) in this species in the Atatürk Dam Lake, Turkey.

The nominal subspecies zarudnyi has 3-4 first dorsal fin spines, 1-2 spines and 5-7 soft rays in the second dorsal fin, the anal fin has 3 spines and 5-9 soft rays, usually 9, and scales in lateral series 41-46. The larger scales distinguish it from the typical form at Mosul in Iraq (Berg, 1949). My observations on the types show 4(4) first dorsal fin spines, 1(2) or 2(2) second dorsal fin spines and 7(3) or 8(1) soft rays, 7(1), 8(1) or 9(2) anal fin soft rays, 5(4) pelvic fin rays, 13(1) or 14(3) branched pectoral fin rays, and 39(1), 43(1), 44(1) or 45(1) scales in lateral series. One specimen is unusual in having a mix of abnormally low counts and normal counts: 3 first dorsal fin spines, 5 second dorsal fin soft rays, 5 anal fin soft rays, 5 pelvic fin rays, 15 pectoral fin rays, and 43 lateral series scales.

Meristic values for Iranian specimens, excluding the above: first dorsal fin spines 4(36); second dorsal fin soft rays 7(4), 8(31) or 9(1); anal fin soft rays 8(28) or 9(8); pectoral fin branched rays 13(1), 14(17), 15(13) or 16(4); pelvic fin branched rays 5(35) or 6(1); lateral series scales 44(5), 45(5), 46(5), 47(8), 48(2), 49(4), 50(1) or 51(1); and total vertebrae ?.

Sexual dimorphism

Unknown.

Colour

The back is a light brown or greyish or olive-green with the flanks and belly silvery or yellowish-silver. There may be an indistinct silvery stripe or 2 grey stripes along the flank. Generally the upper flank is dark, the lower flank pale, and the two clearly demarcated. The upper part of the lower flank may bear alternating light and dark stripes but these are sometimes poorly expressed. The second dorsal and caudal fins are dusky to brownish and lower fins are yellowish-white to hyaline. Scale margins are covered in small black spots. The top of the eye is lime-green and reddish-brown just below but still silvery around the pupil generally. Young fish have a reddish colour at the base of the pelvic, anal and caudal fins and have an evident mid-lateral stripe against a pale body.

Size

Attains 26 cm total length and 0.15 kg.

Distribution

Found in the Tigris-Euphrates and Orontes (= Asi) (Özdilek, 2003) river basins including the Tigris River basin in Iran in rivers and marshes, in lower reaches of rivers draining to the Persian Gulf, and in Pakistan. In Iran it is also recorded from Parishan (= Famur) Lake but it was not captured in a 1995 survey. A record from the Barm-e Shur near Shiraz is probably an introduction as this species was not caught there in the 1970s by me (Gh. Izadi, pers. comm., 2001).

Abdoli (2000) maps this species in the lower Hasan Langi, Kul, Gowdar and Mehran rivers at the Straits of Hormuz in the Hormozgan basin; the lower Mand River and the lower Zohreh (= Hendijan) rivers in the Gulf basin, the Arvand, lower Karun, lower Karkeheh and the Simarreh rivers in the Tigris River basin..

Zoogeography

As a freshwater member of a genus with many species in the sea, its origins lie with these marine relatives.

Habitat

This mullet is a freshwater species found in rivers, streams, channels, canals and drains, lakes, reservoirs and ponds, on fish farms of Iraq and neighbouring countries, occasionally entering estuaries. It usually occurs in schools. Epler et al. (2001) found it to be the dominant species of fish in lakes Habbaniyah, Tharthar and Razzazah, Iraq, comprising 72% of all fish collected. This was one of the most abundant species in the recovering marshes of southern Iraq in 2005-2006 (at almost 36% of 16,199 fishes collected)(Hussain et al., 2006) and in the marshes in the 1980's (Hussain and Ali, 2006). Nasir and Na'ama (1988) and Hussain and Naama (1989) report it from the Khawr az Zubayr in a marine environment, probably a consequence of human-induced environmental changes. It is the most abundant species in autumn in the Karun River, Iran, comprising 44.2% of the catch (Mokhayer, 1981c).

van den Eelaart (1954) reporting on Iraqi populations found this mullet in the surface waters and submerged vegetation of lakes and marshes, preferably where there is a gentle water flow. In December-January it enters rivers and deeper waters, especially in very cold winters. Ahmad et al. (1983; 1985) have shown this species can withstand abrupt increases of temperature up to 30°C and salinity up to 10‰ for 24 hours under experimental conditions. Mortality in water at 15‰ is low. Salinities up to 30‰ and temperatures up to 35°C are tolerated, presumably if increases are gradual. Ahmed et al. (2002) stated that it prefers salinities not exceeding 2‰ (later 5.6‰) but can survive abrupt transfer to 15‰. S. Cowton (pers. comm., 23 August 2005) has observed schools of this species gaping at the surface in the artificial lake around Al Faw Palace in Baghdad, presumably in response to high temperatures and low oxygen. It is often the dominant species left in small pools when marshes dry up, as in the Shadegan Marshes of Iran observed by B. W. Coad.

Age and growth

Al-Nasiri and Islam (1978) studied the age and growth of this species from commercial catches in the Shatt al Arab, Iraq. Specimens were aged by examining the otoliths and three age groups determined with 0+ fish being 8.9-10.9 cm, 1+ fish being 9.9-14.8 cm and 2+ fish being 13.6-18.2 cm total length. Length-otolith formulae were given. Al-Yamour et al. (1988) examined a population of this species in the Al-Daoodi Drain, Baghdad and found an age span up to 7 years using scales to age fish. Older age groups (5 and 6) grow more slowly than Diyala River fish, perhaps because of higher salinity in the Drain and the enriched conditions in the Diyala River due to sewage. The length-weight relationship was W = 0.034 L^2.6, for males W = 0.062 L^2.396,and for females W = 0.031 L^2.642. The condition factor was 6.308 for males and 3.155 for females. Khalaf et al. (1986) studied a population in the Diyala River, Iraq which was polluted with sewage from the Rustamiyah treatment plant. Khishni is the second dominant species from December to March after Chondrostoma regium and in August the dominant species in catches. Fish were heavier and in better condition in the more polluted areas, but probably not as good for human consumption! Growth declines after age group 5 with few fish in age group 6. Length-weight relationships were W = -3.39 L^2.64 for males and W = -2.96 L^2.50 for females. Mhaisen and Yousif (1989) examined a population of khishni in Mehaijeran Creek, a side branch of the Shatt al Arab south of Basrah, Iraq. Only 3 age groups (0+ to 2+) are reported since the creek water level is affected by the tide and older fish tend to move into the deeper waters of the adjacent Shatt al Arab. Growth is faster in the creek than in other Iraqi locations. The length-weight relationship was log W = 2.794 log TL - 1.64840 for males and log W = 3.337 log TL - 2.25728 for females. Mhaisen and Al-Jaffery (1989) report 6 age groups for fish from Babylon Fish Farm west of Hilla, Iraq with a total length-weight relationship log W = 2.96057 log L - 11.19599 (and for standard length log W = 2.87574 log SL -10.24769). Fish were in good condition as they were taking food meant for cultured carp. The relative condition factor was 0.98-1.04, similar to values obtained by other authors. The von Bertalanffy growth equation was TL_t = 409.6 {1 - exp [-0.06314 (t - 3.13868)]}. Al-Shamma'a et al. (1995) examined fish from the Tigris River at Al-Za'faraniyah, Iraq and found log total weight = -2.033 + 3.119 log total length (r= 0.955). Epler et al. (2001) found the oldest age groups to be 4+ in Iraqi lakes Habbaniyah and Razzazah and 5+ in Lake Tharthar. The mean condition factor was 0.97, 1.05 and 1.09 in lakes Habbaniyah, Tharthar and Razzazah respectively. Syzpuła et al. (2001), studying age and growth in the lakes Habbaniyah, Tharthar and Razzazah in 1981 and 1982, found this species grew fastest in Lake Tharthar. A decrease in length growth was noted in the second year of life and a decrease in body mass in the last years of life.

The effect of starvation over 35 days on the proximate chemical composition of this species was studied by Yesser et al. (1999). They found a sharp decline in lipid content (4.38 to 0.98%), a slight drop in protein and an increase in both moisture and ash. Both condition factor and viscera somatic index declined gradually, 1.2 to 0.83 and 10.18 to 3.63% respectively. Body weight fell by 30.59%. Lipid reserves in muscle were therefore an important form of energy storage.

Ünlü et al. (2000) report age groups of 1+ to 4+ in the Turkish Tigris River. Hussain et al. (1987) found condition factor to range from 1.12 to 1.64 for different length groups for Karkheh River fish from Iran near the Iraq border and Hawr al Hawizah.

Food

Al-Nasiri et al. (1977) studied the feeding ecology of this species in the Shatt al Arab, Iraq. Aquatic plant parts and phytoplankton are food items but the vast bulk of material is sand grains and organic detritus, the former presumably ingested while searching for detrital food. Phytoplankton is made up of diatoms (50%), green algae (36%) and blue-green algae (14%), with diatoms the most abundant numerically. Plant parts are fragments of Vallisneria leaves and rarely leaves and stems of Potamogeton and Polygonum. Islam et al. (1981) reported on the seasonal patterns of feeding in Rashdiyah Reservoir, Baghdad. However it should be noted that only 10 fish were examined for each month. Aquatic plant parts, organic debris and phytoplankton are dominant foods followed by zooplankton and aquatic insects. The diet is diverse, 48 species of Chlorophyceae, 60 species of Bacillariophyceae, 9 species of Myxophyceae and 3 of Euglenophyceae. Heavy feeding occurs in late winter, spring and fall with peaks in April and November. Empty stomachs are more common in summer. Islam and Khalaf (1983) studied diel feeding patterns in the same reservoir and found peaks at 0600 and 2100 hours. Naama and Muhsen (1986) studied the feeding periodicity of this species in the Hawr al Hammar, Iraq and found the main food to be algae, mixed with incidental sand grains. There is a single feeding peak each day at 1730 hours and feeding stops at 0200 hours. This species is a day feeder. In another study of the recovering Hawr al Hammar, diet was 76.49% algae and 20.3% diatoms with amounts of crustaceans and plants being less than 10% each, in the Hawr al Hawizah 74.3% algae and 22.5% diatoms, with amounts of plants and crustaceans being less than 10% each, and in the Al Kaba'ish (= Chabaish) Marsh 75.8% algae and 20.0% diatoms with plants and crustaceans at less than 10% each (Hussain et al., 2006). Ahmed and Hussain (1982) examined the food of young fish near Basrah, Iraq and found organic detritus to be an important food followed by phytoplankton. The smallest fish are consuming eggs in large quantities. Al-Shamma'a and Jasim (1993) studied feeding in the Hawr al Hammar in Iraq during the flood period and reports small quantities of adult insects, chironomid larvae, trichopteran larvae, other insect larvae, molluscs and worms, while copepods, cladocerans, and rotifers are important foods. This variation from the diet studies reported above may be due to the flood not allowing diatoms and algae to settle out and become available as food. Typical foods and gut contents such as organic detritus, algae, diatoms, plant tissues and sand grains are also present. Sand grains may help in trituration of food and therefore are not an accidental inclusion. Al-Shamma'a et al. (1995) examined fish from the Tigris River at Za'faraniyah and found phytoplankton ranked first in the diet followed by detritus. Debris comprised more than 37% of stomach contents on the points method. Epler et al. (1996) found detritus to be the main food in three Iraqi lakes. Epler et al. (2001) found detritus to be 83.7% of the diet in Lake Tharthar, mineral parts (presumably sand) 12.7% and plants 3.6%. In Lake Habbaniyah detritus was 73.0%, mineral parts 16.5% and plants 8.4%. In Lake Razzazah detritus was 84.4%, mineral parts 14.7% and plants 0.9%. Detritus was the principal food year round with no seasonal variations. Hussain and Ali (2006) examined feeding relationships among fishes in the Hawr al Hammar and found this species to be a herbivore, 39.6% of the diet being plants and algae, with 18% detritus.

Hussain et al. (1987) examined the food of khishni in the Karkheh River, Khuzestan, where it is the dominant species in terms of numbers caught, by two orders of magnitude. However capture techniques would affect this assessment. Food was similar to that reported from Iraqi fish. Phytoplankton is the most important food for fish 3.0-3.9 cm long, followed by organic detritus, while in larger fish this order is reversed. Silt is an important content of the gut in all fishes studied. Eighteen species of Bacillariophyceae, 6 Chlorophyceae and 4 Cyanophyceae species were recorded from gut analyses. Abdoli (2000) reports Daphnia, Hemiptera, Navicula, Nitzschia, Amphora and Cymbella species for Iranian specimens.

Reproduction

Marammazi (1994) considered it likely that this species spawns twice each year in the Zohreh River, Iran draining to the northern Persian Gulf.

van den Eelaart (1954) gave the spawning season in Iraq as end of February to mid-March. In the Al-Daoodi Drain at Baghdad and the Hawr al Hammar of southern Iraq spawning starts in March and continued through May (Al-Yamour et al., 1988). Mean number of eggs reaches 59,793, increasing with size and weight. In the study by Khalaf et al. (1986), all age group 1 fish are mature and females outnumber males in age groups 2 to 6 although this may be due to sampling bias. Ünlü et al. (2000) report maturity at age 1 in the Turkish Tigris River based on gonad development, with no spawning in the period August to February. Mhaisen and Yousif (1988) examined a population of khishni in Mehaijeran Creek, a side branch of the Shatt al Arab south of Basrah. Fish are ripe from January to March and females partly spent in April and spent in May. The fish spawn once. All males and females were mature at 16 cm in the creek while females mature at 13 cm in the Hawr al Hammar. Some males matured at 10.5 cm and some females at 10.6 cm in the creek. Naama et al. (1986) studied reproduction in the Hawr al Hammar and found a prolonged breeding period from November to April during which two batches of eggs could be shed. Maturity is attained at the end of the first year of life for both sexes when they are about 10 cm total length, with all males mature at 16 cm and all females at 13 cm. Egg diameter is up to 0.75 mm. Epler et al. (1996) record a relative fecundity of 359,873 to 756,118 eggs for fish of age groups 1+ to 3+ from three lakes in Iraq. Mature eggs were found from January to May in one lake and from November to March in another, maturity being two months earlier in saltier water. Daoud et al. (1998) examined reproductive biology in fish from the Tigris River at Al-Khadhmia north of Baghdad. They found a sex ratio of 1:1.45 (male:female), significantly different from 1:1, a breeding season from December to March, sexual maturity in all fish longer than 10 cm total length, smallest mature male 10.4 cm, smallest mature female 10.6 cm, absolute fecundity 12,033-63,836 eggs and relative fecundity 1237 eggs/g. Epler et al. (2001) studied reproduction in lakes Tharthar and Habbaniyah and found both sexes to achieve maturity in the first year of life at 14.2 cm. Spawning occurred in May and fecundity was 652-791 thousand eggs/kg body mass. Eggs are shed on, and adhere to, vegetation.

Rashid (19940 gives details of the histological changes in the ovaries for fish from the Qarmat Ali canal, along with several indices. The gonosomatic index showed no significant change from October to December but increased from 3.03 in December to 9.43 in January and 16.4 in February, decreasing subsequently suggesting a gradual spawning took place in March and into April. The hepatosomatic index showed a significant increase in February to 3.34 and a significant decrease in March to 1.32, suggesting the liver was involved in vitellogenin synthesis necessary to oocyte development. The somatic index increased from 0.65 in October to 1.15 in December as the fish lay down reserves, decreasing to 0.53 in February and rising throughout March and April.

Parasites and predators

Bykhovski (1949) reports a new species of monogenetic trematode, Ancyrocephalus fluviatilis, from this species in the Karkheh River, Iran. Mokhayer (1981c) reports a high infestation rate with larvae of the nematode Contracaecum in Karun River fish. This has health consequences for humans if fish are eaten raw, or are inadequately salted, smoked or cooked. There has been no report yet of this parasite from humans in Iran.

Moghainemi and Abbasi (1992) record a wide range of parasites from this species in the Hawr al-Azim in Khuzestan. Mortazaei et al. (2000) report the worm Neoechinorhynchus tylosuri in 54.8% of fish examined from Khuzestan marshes. Farahnak (2000) and Farahnak et al. (2002) record Anisakidae from this species in Khuzestan.

Economic importance

It appears in stores as a regular food fish in Ahvaz, Khuzestan, and is an important food fish in southern Iraq (Al-Nasiri and Islam, 1978) with 212,850 kg marketed at Basrah from October 1975 to June 1977 (Sharma, 1980). It forms about 29% of the total annual catches of freshwater fishes in southern Iraq and about 7.4% of the total annual catch for the whole country despite its small individual size (Mhaisen and Yousif, 1989; Mhaisen and Al-Jaffery, 1989). Its caloric value is 162.42 Kcal/100g (Mahdi et al., 2005). Salim (1962) records this species jumping into boats in Iraq when attracted by lights. It is important on fish farms in Iraq where it competes for food with cultured carp (Al-Shamma'a and Jasim, 1993) and Mhaisen and Al-Jaffery (1989) believed it could be farmed successfully because of its high growth rate. Taken also in the subsistence fisheries of the Indus River in Pakistan.

van den Eelaart (1954) gave the fishing season for this species as December-January (peaking in January) in rivers, and December-March (January) for lakes and marshes in Iraq.

Balasem et al. (2000) showed this species to be more sensitive to pollution than other Iraqi species tested, namely Barbus luteus, Cyprinus carpio, Carassius carassius (sic, probably C. auratus) and Gambusia affinis (sic, probably G. holbrooki). The LC₅₀ of L. abu to copper after 72 hours exposure was 0.4 p.p.m. while the other species showed no mortality at this level. L. abu was also more sensitive to arsenic than these species and also Barbus sharpeyi, B. xanthopterus, B. grypus and Ctenopharyngodon idella (Ali et al., 1999). Wahab (1999) also tested the toxicity of four organophosphate insecticides to young fish, namely Dursban, Superacid, Malathion and Nogos with LC₅₀ at 0.102. 0.125, 0.875 and 1.2 5 mg/L respectively. Salinity has a significant effect on the toxicity. This mullet has also been used to assess the impact of gas oil from oil spills in the Shatt al Arab on ionic regulation, on the chloride cells and on the gills (Faddagh et al., 2004). It was found to be sensitive to this form of pollution and suitable as an indicator species.

Conservation

Mhaisen and Yousif (1988) recommend banning fishing from mid-January to mid-May during the spawning season and instituting an increase in fishing net mesh size to 23.2 mm.

Further work

Variation in this species should be re-examined to determine if nominal species and subspecies are valid. Biology and stock assessments for Iranian waters need to be carried out.

Sources

Type material: Liza abu zarudnyi (ZISP 24336).

Iranian material: CMNFI 1979-0240, 3, 57.1-70.7 mm standard length, Fars, Lake Famur (ca. 29º31'N, ca. 51º50'E); CMNFI 1979-0304, 12, 21.5-50.0 mm standard length, Fars, Lake Famur (ca. 29º31'N, ca. 51º50'E); CMNFI 1979-0352, 5, 11.4-22.6 mm standard length, Khuzestan, marsh 57 km east of Abadan (30º33'30"N, 48º48'E); CMNFI 1979-0353, 3, 15.7-18.3 mm standard length, Khuzestan, Karun River (30º22'30"N, 48º17'E); CMNFI 1979-0354, 6, 18.4-25.2 mm standard length, Khuzestan, Karun River tributary (30º31'N, 48º19'E); CMNFI 1979-0355, 3, 16.7-29.4 mm standard length, Khuzestan, Karun River tributary (30º35'N, 48º22'E); CMNFI 1979-0360, 12, 17.7-35.8 mm standard length, Khuzestan, canal branch of Karkheh River (31º40'N, 48º35'E); CMNFI 1982-0369, 11, 39.3-57.9 mm standard length, Khuzestan, Karkheh River (no other locality data); CMNFI 1993-0149, 2, 106.0-142.2 mm standard length, Khuzestan, Karun River (no other locality data); ZSM 25387, 4, 56.6-90.9 mm standard length, Khuzestan, Karun River at Ahvaz (31º19'N, 48º42'E); ZSM 25700, 6, 41.0-57.4 mm standard length, Khuzestan, fish pond near Ahvaz (no other locality data); uncatalogued 1, 169.8 mm standard length, Khuzestan (no other locality data).

Comparative material: BM(NH) 1971.4.2:1, 1, 130.2 mm standard length, Iraq, pond 25 km from Mosul (no other locality data); BM(NH) 1973.5.21:179-184, 6, 41.4-51.4 mm standard length, Iraq, Tigris River at Jadriyah, Baghdad (no other locality data); BM(NH) 1974.2.22:10-13, 4, 107.3-119.5 mm standard length, Iraq, Najab Bazar (no other locality data).

Liza aurata
(Risso, 1810)

Common names

kefal-e auratus, mahi kefal-e talaee (= golden mullet fish), kefal-e zarin, kafal.

[gizili kefal in Azerbaijanian; gatykelle, singil, orsbalyk in Turkmenian; singil' in Russian; golden mullet, golden grey mullet, long-finned mullet].

Systematics

Mugil Auratus was originally described from Nice, France. No major relevant synonyms.

Key characters

This species is distinguished from its relative in the Caspian Sea by each head and antero-dorsal flank scale having only one pit or groove (occasionally double), 6-10 pyloric caeca of about equal length or gradually becoming longer from ventral to dorsal, scales on the snout ending anteriorly as a single row of small scales, and the oral edge of the preorbital bone is moderately concave. The upper jaw reaches posteriorly to a level with the posterior nostril, the only species in the genus with this character. Young have two vertical dark lines at the origin of the caudal fin rays and a herring bone pattern on the flanks (Harrison in Miller, 2003).

Morphology

The first dorsal fin has 4 strong spines, the last weakly developed compared to the first three. The second dorsal fin has 1-2 weak spines (more resembling unbranched rays than spines) and 6-9, usually 7 or 8 soft rays (the second unbranched ray or spine may be branched near the tip - the mode of 8 may include this ray in literature sources). The anal fin has 3 spines and 7-10, usually 9 branched soft rays. The pectoral fin has 2 unbranched rays and 13-17 branched rays and the pelvic fin has 1 spine and 5 branched rays. Scales number 40-49 in lateral series. There is no pectoral axillary scale. There is an elongate first dorsal fin axillary scale and a pelvic axillary scale. Scales have an almost vertical anterior margin with the anterior dorsal and ventral corners square to pointed. This margin is slightly indented where radii intersect it. The dorsal and ventral scale margins are parallel and the posterior margin is rounded. The focus is posterior and the posterior field has weak ctenii. Circuli are fine and numerous and radii are limited to the the anterior field, numbering up to 13 in fish examined here but probably size dependent. The adipose membrane of the eye is rudimentary. The gill rakers are fine and numerous, apparently finer and more numerous than in Liza saliens, exceeding 100 in the larger fish examined here. Raker number is probably size dependent. Rakers are slender, compressed and serrated medially. When appressed, a raker reaches the thirteenth raker below. The gut is elongate with several anterior and posterior loops after a muscular stomach. The chromosome number is 2n=48 (Klinkhardt et al., 1995).

Meristic values for Iranian specimens are:- first dorsal fin spines 4(30); second dorsal fin with 1(3) or 2(27) "spines" or unbranched rays and 6(1), 7(27), 8(1) or 9(1) branched rays; pectoral fin unbranched rays 2(30) and branched rays 15(7), 16(20) or 17(3); pelvic fin branched rays 5(30); lateral line scales 41(2), 42(4), 43(8), 44(3), 45(8), 46(4) or 47(1); and total vertebrae ?.

Sexual dimorphism

Unknown.

Colour

The body is a dusky grey to blue-grey with a silvery flank and belly. The back and upper flank have a series of dark to golden stripes. There is a golden blotch on the operculum. The peritoneum is dark brown to black. See also Key characters.

Size

Commercial catches in Iran during the 1950s weighed 0.3-0.8 kg, sometimes as much as 1.5-1.8 kg (Farid-Pak, no date). Reaches 59 cm and 2.5 kg on the coast of Turkmenistan. The Fisheries Research Centre in Mazandaran caught an exceptional specimen of this species weighing 1.5 kg and measuring 54 cm long (Iranian Fisheries and Research Training Organization Newsletter, 3, 1994).

Distribution

Found in the Mediterranean and Black seas and from the British Isles south to South Africa.

First reported from Iranian waters in 1933 by Shukolyukov (1937a) and by Dmitriev (1946), this species and Liza saliens became acclimated to the Caspian Sea over a period of 30-35 years and are regarded as naturalized from the latter half of the 1960s onward in Soviet waters (Marti, 1940; 1941; Khoroshko, 1982). It was first introduced to the Soviet Caspian Sea in 1930-1931 (Baltz, 1991). Kaplin in Mandych (1995) indicates that these grey mullets entered from the Black Sea during a Caspian transgression but this is incorrect.

In Iran, this species is found in the lower reaches of rivers along the Caspian coast, the Anzali Mordab and its outlets where numbers will probably increase with increasing salinity (Holčík and Oláh, 1992), the Safid River, Gorgan Bay, the southeast Caspian Sea, southwest Caspian Sea and south-central Caspian Sea (Abbasi et al., 1999; Kiabi et al., 1999).

Zoogeography

This species is an exotic in Iran.

Habitat

This mullet inhabits the sea and enters the lower reaches of rivers, and is occasionally found in nearby lakes. It is recorded from depths of 5-700 m (Caspian Sea Biodiversity Database, www.caspianenvironment.org). Eggs develop in the open sea, larvae migrate to the coast and young feed along the shore and in bays. It winters along the Iranian shore in coastal waters, has a feeding migration in surface waters beginning in March to shallow areas of the middle Caspian and, by September-October, mature fish migrate over deeper water (300-700 m) of the middle and south Caspian to spawn. Feeding ceases at 6-8ºC and death occurs below 1.5ºC. The optimum temperature is 23-25ºC but young can be found in shallow water at 37.5ºC. It occurs from fresh water to salinities of 57‰ with mass mortalities recorded at 65‰ (Caspian Sea Biodiversity Database, www.caspianenvironment.org). Amini Ranjbar and Sotoudebnia (2005) assessed heavy metal (Zn, Cu, Pb and Cd) concentrations in fish from the Caspian Sea in Mazandaran and found higher than normal levels of Pb and Cd in muscle tissues.

Age and growth

Life span is up to 12 years in the Caspian Sea (Khoroshko, 1982). Maturity is attained at 38-45 cm and an age of 3-4 years for males and 5-6 years for females (RaLonde and Walczak, 1972). Fish taken from commercial catches in Iran are mostly 3-7 years old, 30.2-49.1 cm long and weigh 354-1266 g (Razivi et al., 1972). Fazli (1998) studied this species in the southeastern Caspian Sea of Iran and found that both scales and opercula could be used in ageing, although the  latter were better. Maximum growth occurred at 3 years of age. The b value in the relation between length and weight was 3.019 and sex ratio was 1:1.3 with females dominating.

Food

This species is reported to enter the Anzali Mordab to feed from January to March (Holčík and Oláh, 1992), a result of the increasing salinity of this lagoon. Food items are small benthic invertebrates and detritus with some insects and plankton. Most stomach contents contain numerous sand grains. Adults scrape periphyton from rocks, silt and artificial structures.

Reproduction

This mullet spawns in more northerly waters of the Caspian than its relative Liza saliens. Spawning begins in the middle of July in the middle Caspian and ends in the south Caspian from the middle to the end of October. Intensive spawning in the middle Caspian takes place in August-September at 20-22°C and a transparency of 7-11 m. Spawning depth is in the upper 0.5 m. The main spawning areas are at least 50-60 miles (80-96 km) from the coast (Avanesov, 1972) and this prevents the spawning area being easily exploited. Fecundity exceeds 4.4 million eggs in the Caspian Sea (Khoroshko, 1982); in Mazandaran average absolute fecundity reaches 772,350 eggs (Abdoli et al., 1996). The eggs are pelagic and have a diameter of 0.9 mm. In Iran, Gorgan Bay is believed to be a very important nursery and this is the major species caught by fishermen in winter (www.ramsar.org/ram_rpt_37e.htm, downloaded 28 July 2000). Shabanipour (1995) and Shabanipour and Heidari (2004) carried out histomorphological studies on the ovary of this species in Iran. Fazli (1998) found populations in the southeastern Caspian Sea of Iran spawned in September-November based on the gonadsomatic index, with most spawning in October. Males are ready to reproduce earlier than females. Absolute fecundity was 586,165 eggs.

Parasites and predators

Mokhayer (1976b) records the trematode Saccocoelium obesum from this species on the Iranian coast. This is a parasite of the intestine, with contamination rates of 90.4%, 88.6%, 81% and 34% for autumn, winter, spring and summer respectively. Gills carry Microcotyle mugilis at a rate of 2.0-2.3% and fish are also infected with Ancylodiscoides (sic) at a rate of 19.6%, 43%, 72% and 43.3% for autumn, winter, spring and summer respectively (Annual Report, 1994-1995, Iranian Fisheries Research and Training Organization, Tehran, p. 27-28, 1996; Annual Report 1993-94, Iranian Fisheries Research and Training Organization, Tehran, p. 49-50, 1995). Naem et al. (2002) found species in the monogenean treamtode genus Ligophorus on the gills of this species from the western branch of the Safid River.

This species is eaten by Sander spp., Silurus glanis and Huso huso.

At Ziba-kenar beach, Gilan in February 2004, this species showed erratic swimming and belly-up posture. A post-mortem showed gas accumulation and distension in the swimbladder, a yellowish liver, liquefaction of the gall bladder, excess micro-sand in the the caecum and hyperaemia of the intestine. The cause is thought to be an infectious agent closely related to a betanovirus or nodavirus (Iranian Fisheries Research Organization Newsletter, 38:3, 2004; Zorriehzahra et al., 2005).

Economic importance

The catch in Iran for this species and Liza saliens from 1956/1957 to 1961/1962 varied from 166,197 kg to 960,282 kg (Vladykov, 1964) and from 1965/66 to 1968/69 varied from 490 to 1916 tonnes (Andersskog, 1970). Vladykov (1964) and RaLonde and Walczak (1972) cite figures for the Bandar-e Anzali region for Liza aurata from 1937/38 to 1961/62 of 14 kg to about 113 t and for 1969/70 a catch of 1,085 t was recorded, while for the whole Northern Shilot (Fisheries Company) in the period 1965/66 to 1968/69 catches varied between 548 t and 1916 t. Holčík and Oláh (1992) report a catch of only 3 kg in the Anzali Mordab in 1990. The Food and Agriculture Organization, Rome records the following catches for the 6 years from 1980 to 1985 for mullets in Iran, presumably from the Caspian Sea:- 150, 400, 1500, 2733, 2135, and 2200 t respectively. Moghim et al. (1994) give a total biomass of 2400 tonnes for this species in the southern coastal area of the Caspian Sea with a maximum sustainable yield of 960 tonnes (figures for Liza saliens are 7000 tonnes and 2900 tonnes respectively). Caspian Sea catches of this species in Iran for the year 1993-1994 was 22% of the bony fish catch with Liza saliens comprising only 4% (the major part of the catch was safid mahi, Rutilus frisii, at 62%)(Annual Report 1993-94, Iranian Fisheries Research and Training Organization, Tehran, p. 83, 1995). Catches in former Soviet waters of the Caspian Sea are about three-quarters or more this species and one-quarter Liza saliens (Khoroshko, 1982). The main season for fishing in the Caspian Sea off Iran is from December to February, peaking in January (Farid-Pak, no date). Abdoli et al. (1996) note that beach seiner cooperatives started fishing a month earlier than usual in 1993, coinciding with the spawning season in October. Annual catch variations occur in Iranian waters, this species having an abundance of 86.5% in 1994 decreasing to 38% in 1995 (Iranian Fisheries Research and Training Organization Newsletter, 9:5, 1995). The catch of this species declined from 76.9% to 41.2% of the total mullet catch from 1993-1994 to 1994-1995 through overfishing of juveniles (Iranian Fisheries Research and Training Organization Newsletter, 11:7, 1996). Abdolmalaki (2001) records a catch per unit effort for beach seining as 93 kg in 1991, falling to 33 kg in 1997 through overfishing. The mean length of the catch in Guilan decreased from 1991 to 1997 while in Mazandaran it increased. Fazli and Ghaninejad (2004) give the year 2001 as that of the maximum mullet catch in their survey of the years 1993-2001, the catch increasing through this period. Catch per unit effort in each seine declined from 114 kg in 1993 to 43 kg in 1996, increasing to 66.4 kg and 78.4 kg in 2000 and 2001. For the years 2000 and 2001, L. aurata had a mean fork length of 32.7 and 32.3 cm, a weight of 418.3 and 419.8 g, and a K value of 0.61 and 0.93. They concluded that the harvest of this species is at a sustainable level. Heydatifard et al. (2002) state that its catch is greater than that of other bony fishes (presumably excluding kilka) in the southern Caspian Sea.

Hosseini et al. (2004) determined the shelf life of this species on ice in Iran was 10 days. Mazandaran fish have an average fat composition of 9.25%, 72% being unsaturated. Omega-3 fatty acids constitute 18.7% of the total fatty acids with a significant ratio to omega-6 fatty acids of 1.97 (Bedayatifard et al., 2002). Akhondzadeh Basteh et al. (2006) found the bacterial pathogens Listeria monocytogenes and Staphylococcus aureus in salted Liza aurata and Vibrio haemolyticus in fresh and salted L. auratus.

Conservation

The successful introduction of this species and Liza saliens in the Caspian Sea has apparently led to a decline in various clupeid species (Alosa) and of Sander marinum (Baltz, 1991). Beach seines with mesh sizes of 28 mm, 33 mm and 36 mm caught non-standard fish as 43.3%, 35% and 2.2% of the total catch respectively. Seines with a cod end of at least 36 mm are recommended for stock protection (Iranian Fisheries Research and Training Organization Newsletter, 6:8, 1994) (note the report names the fish as Mugil cephalus but the catch was probably a mix of Liza aurata and L. saliens). Contamination of this species in Iranian waters with Pb, Ni and Zn was examined by Fazeli et al. (2005). The highest contamination was in the southwest part of the Caspian followed by the south centre and the southeast. The highest concentrations observed were 17.51 mg/kg for lead, 6.23 mg/kg for nickel and 647.28 mg/kg for zinc.

Further work

As an important fisheries species, population numbers and biology should be carefully monitored on an ongoing basis.

Sources

Distinguishing characters based on Trewavas and Ingham (1972); Sakri (1993) gives an account in Farsi on the spawning and catch of mullets in the Iranian Caspian.

Type material: None.

Iranian material: CMNFI 1970-0509, 1, 124.2 mm standard length, Gilan, Safid River (37º24'N, 49º58'E); CMNFI 1970-0535, 1, 137.2 mm standard length, Gilan, Shafa River (37º35'N, 49º09'E); CMNFI 1970-0543, 3, 33.5-38.5 mm standard length, Gilan, Caspian Sea at Hasan Kiadeh (37º24'N, 49º58'E); CMNFI 1970-0543A, 4, 33.1-60.5 mm standard length, Gilan, Caspian Sea at Hasan Kiadeh (37º24'N, 49º58'E); CMNFI 1970-0563, 19, 52.8-87.0 mm standard length, Gilan, Caspian Sea, Kazian Beach (ca. 37º29'N, ca. 49º29'E); CMNFI 1970-0565, 4, 52.2-93.0 mm standard length, Gilan, Safid River estuary (ca. 37º28'N, ca. 49º54'E); CMNFI 1970-0581, 2, 147.7-151.5 mm standard length, Gilan, Caspian Sea near Hasan Kiadeh (37º24'N, 49º58'E); CMNFI 1970-0587, 1, 78.9 mm standard length, Mazandaran, Babol River (36º43'N, 53º39'E); CMNFI 1971-0326A, 20, 30.0-46.0 mm standard length, Gilan, Caspian Sea near Bandar-e Anzali (37º28'N, 49º27'E); CMNFI 1979-0430, 1, 42.0 mm standard length, Mazandaran, river 1 km east of Now Shahr (36º39'N, 51º31'E); CMNFI 1979-0470, 19, 29.4-57.4 mm standard length, Mazandaran, stream 21 km west of Alamdeh (36º35'N, 51º43'E); CMNFI 1979-0471, 3, 56.7-65.8 mm standard length, Mazandaran, Caspian Sea 14 km west of Alamdeh (36º35'N, 51º48'E); CMNFI 1979-0686, 2, 59.1-87.3 mm standard length, Gilan, Safid River near Hasan Kiadeh (37º24'N, 49º58'E); CMNFI 1980-0117, 2, 99.7-114.5 mm standard length, Gilan, Golshan River (37º26'N, 49º40'E); CMNFI 1980-0127, 6, 29.5-36.9 mm standard length, Gilan, Caspian Sea near Hasan Kiadeh (37º24'N, 49º58'E); CMNFI 1980-0146, 1, 135.7 mm standard length, Mazandaran, Gorgan Mordab at Ashuradeh-ye Kuchak(36º50'N, 53º56'E); CMNFI 1980-0149, 1, 38.4 mm standard length, Gilan, Chabak River (37º21'N, 49º50'E).

Liza saliens
(Risso, 1810)

Common names

kefal-e saliens, kafal-e poozehbarik, kafal.

[sivriburun kefal in Azerbaijanian; vitibutum or gatykelle in Turkmenian; ostronosik in Russian; sharpnose mullet, small mullet, grey mullet, leaping mullet].

Systematics

Mugil Saliens was originally described from Nice, France. No major relevant synonyms.

Key characters

This species is distinguished from its relative in the Caspian Sea by each head and antero-dorsal flank scale having 2-7 or more grooves (mostly 2 grooves), pyloric caeca in two groups, 3-5 short and 3-4 long (total 7-9), scales on the snout ending anteriorly as numerous rows of small scales, and the oral edge of the preorbital bone is deeply notched. Young lack the vertical dark lines at the origin of the caudal fin rays and the herring bone flank pattern seen in L. aurata (Harrison in Miller, 2003).

Morphology

The first dorsal fin has 4 spines, the last one weakly developed compared to the first three. The second dorsal fin has 1-3, usually 1or 2, spines (more resembling unbranched rays than true spines) and 6-9, usually 8 or 9 soft rays (the second unbranched ray or spine may be branched near the tip - modes of 8 or 9 in literature may include this ray). The anal fin has 3-4, usually 3, spines and 7-10, usually 9, soft rays. The pectoral fin has 2 unbranched rays and 14-17 branched rays and the pelvic fin has 1 spine and 5 branched rays. Scales number 42-50 in lateral series. There is no pectoral axillary scale. There is an elongate first dorsal fin axillary scale and a pelvic axillary scale. Scales have an almost vertical anterior margin with the anterior dorsal and ventral corners square to pointed. This margin is slightly indented where radii intersect it. The dorsal and ventral scale margins are parallel and the posterior margin is rounded. The focus is posterior and the posterior field has weak ctenii. Circuli are fine and numerous and radii are limited to the the anterior field, numbering up to 10 in fish examined here but probably size dependent. The gill rakers are fine and numerous, but not as fine and numerous as in Liza aurata, exceeding 70 in the larger fish examined here, and probably size dependent. When appressed, a raker reaches raker 6 or 7 below. Rakers have a serrated medial edge. Vertebrae 23-25. The gut is elongate with 2 posterior loops after a muscular stomach. The chromosome number is 2n=48 (Klinkhardt et al., 1995).

Meristic values for Iranian specimens are:- first dorsal fin spines 4(30); second dorsal fin with 1(6), 2(22) or 3(2) "spines" or unbranched rays and 6(1), 7(20) or 8(9) branched rays; pectoral fin unbranched rays 2(30) and branched rays 14(2), 15(27) or 16(1); pelvic fin branched rays 5(30); lateral line scales 42(2), 44(6), 46(6), 47(8), 48(4) or 49(4); and total vertebrae ?.

Sexual dimorphism

Males are smaller than females.

Colour

The back is dark grey to blue-grey or grey-brown, the belly pale to silvery or yellowish, and the silvery-grey flanks have about 7 bluish stripes. There is a golden blotch on the operculum. The peritoneum is brown to black.

Size

Commercial catches in Iran during the 1950s weighed 0.3-0.8 kg, sometimes as much as 1.5-1.8 kg (Farid-Pak, no date). Reaches 40.0 cm.

Distribution

Found in the Mediterranean and Black seas and along the Atlantic coast to South Africa.

First reported from Iranian waters by Dmitriev (1946), this species was introduced to the Soviet Caspian Sea in 1930-1931 (Baltz, 1991). In Iran it is reported from the lower reaches of such rivers as the Gorgan, Gharasu, Tajan, Talar, Babol, Haraz, Sardab, Pol-e Rud, and Safid, the Anzali Mordab and Gorgan Bay, the southeast Caspian Sea, southwest Caspian Sea and south-central Caspian Sea (Roshan tabari, 1987; Abbasi et al., 1999; Kiabi et al., 1999).

Zoogeography

This species is an exotic in Iran.

Habitat

This is a pelagic species found mostly in inshore areas and entering lagoons and rivers. It is found in surface waters over depths of 5-700 m at salinities of 4-13‰. It migrates to the southern Caspian in autumn when water temperatures fall (Caspian Sea Biodiversity Database, www.caspianenvironment.org). Generally it tolerates fluctuations of 5-27Cº and 11-28‰ although fry need time to adjust to lower salinities (Harrison in Miller, 2003).

Age and growth