Species Accounts - Sparidae
The sea breams or porgies are found in the Atlantic, Indian and Pacific oceans and comprise 33 genera and about 115 species (Nelson, 2006). Some commonly enter estuaries and penetrate up rivers. Maximum length is about 1.2 m.
This family is characterised by a groove in the distal end of the premaxilla which accommodates the maxilla; the body is oblong to ovate and is compressed; the head is large with a steep upper profile; the preopercle margin is smooth; scales are weakly ctenoid, moderate in size and extend on to the cheeks and operculum; teeth are conical to incisiform and molar teeth are found in some at the rear of the jaw; there are no teeth on the vomer, palatines or tongue; the dorsal fin is continuous with an anterior spiny portion and a soft-rayed posterior portion about equal in size; with 10-13 spines and 10-15 soft rays respectively; spines fold into a groove; the anal fin has 3 spines (the second the largest) and 8-14 soft rays; branchiostegal rays 5-6; branchiostegal rays 5-6; and lateral line not continued onto the caudal fin but with enlarged scales near the head.
Many species in this family are hermaphrodites with male and female sex organs developing simultaneously, changing sex from male to female (protandry), or from female to male (protogyny). These fishes are often important as food or sought by anglers. Young fish may very different in colour to adults, usually being more vividly coloured with distinctive patterns. Most species are marine (see Marine List) but a few enter fresh water and penetrate a considerable distance from the sea including one species in Iran.
Genus Acanthopagrus
Peters, 1855
Members of this genus have a compressed and moderately deep body, 4-6 enlarged incisiform teeth at the front of the jaws followed by 3-4 rows of molars, the second anal fin spine is longer than the third, there is a scaly sheath at the base of the dorsal and anal soft fins, and moderate-sized scales.
Acanthopagrus latus
(Houttuyn, 1782)
Common names
شانك (= shanak), شانك زردباله (= shanak-e zardbaleh or yellowfin shanak).
[shanak, shaghoom, shaam, sha'm, shaem, sheim or sha-om in Arabic; yellow-finned porgy or seabream, yellow-finned black porgy, Japanese silver bream].
Systematics
Sparus latus was originally described from Japan.
Al-Hassan (1990) found differences in two meristic characters (pectoral and dorsal fin ray counts) but no differences in electrophoretic characters between populations from the Shatt al Arab and Khor al Zubair areas of southern Iraq. He concludes that there is only one stock of this species in southern Iraq as meristic variation may reflect environmental conditions.
Key characters
This species is the only sparid member recorded from Iranian freshwaters and is recognised by the dorsal fin spines alternately thick and thin and the colour pattern.
Morphology
Upper profile of head steep and convex back to above the posterior eye margin. The head bulges over the eye. Dorsal fin spines 11-13, soft rays 9-13. Anal fin with 3 spines, the second much stronger and wider than the third, and 8-9 soft rays. Pectoral fin branched rays 10-16. There is a strong spine in the pelvic fin and a well-developed axillary scale. Lateral line scales 41-46, or 48-50, or up to 55 depending probably on differing counting methods. The scales are vertical ovals with the anterior margin wavy where radii intersect. They have very fine circuli, moderate numbers of posterior radii, a subcentral posterior focus, and ctenii on the central part of the posterior margin extending inwards towards the focus. Four or five series of preopercular scales. The first pelvic fin ray is elongated as a small filament. There is a strong pelvic axillary scale. There are 3-4 scale rows sheathing the dorsal and anal fin bases. There are 4-6 compressed teeth in front of each jaw followed by 3-5 rows of molar teeth. The chromosome number is 2n=48 (Klinkhardt et al., 1995). The gut is an elongate s-shape.
Meristic values for Iranian specimens are:- dorsal fin spines 12, soft rays 10, anal fin spines 3, soft rays 8, pectoral fin branched rays 13, scales mostly lost.
Sexual dimorphism
This species is a protandrous hermaphrodite, being male early in its life and then becoming female later. Catches will include males, females and hermaphrodites, e.g. in Abu-Hakima's (1984a) study in Kuwait, there were 326 males, 343 females and 41 hermaphrodites.
Colour
Overall colour is a silvery-grey or silvery-white with the back darker and the belly yellowish. Scales each have a dark, brownish to golden spot at the base which line up to form apparent stripes along the flank. There is a dark blotch at the upper corner of the gill opening, on both the body and gill cover. There is a dark band over the head between the eyes and the edge of the operculum is dark. Dorsal fin spines are white and the membranes are grey, with dark margins between the spine tips. The soft dorsal fin is dark grey with a light orange tinge. There is a small back spot at the pectoral fin base and the fin is mostly hyaline with a light orange tinge. The anal and pelvic fins are a light yellowish-brown. The caudal fin is dark grey on the upper lobe and yellow on the lower with a black margin. The peritoneum is silvery brown in preserved fish with widely scattered melanophores.
Size
Reaches over 50 cm total length.
Distribution
Found from the Persian Gulf to Japan and north Australia. Recorded from the Helleh River in Bushehr Province, Iran (J. Holčík, pers comm., 1995) and from the Bahmanshir River (Marammazi, 1995; Eskandary et al., 1999). Also from the Shatt al Arab in Iraq on the border with Khuzestan in Iran (Al-Hassan et al., 1989; Hussain et al., 1989).
Zoogeography
This marine species enters rivers in southern Iran and presumably freshwater stocks are maintained from this marine gene pool.
Habitat
The usual habitat is over sand and rock bottoms in the sea down to about 50 m, but young fish may enter estuaries and may penetrate considerable distances inland, although some fish remain at sea permanently. The frequency of penetration into Iranian rivers along the Persian Gulf coast is not known. Larger specimens are known to penetrate the Shatt al Arab in autumn, October to December, and this water body is an important nursery for this species, found there year round as young. Adults emigrate from January to March (Al-Hassan, 1990; Hussain et al., 1987). At a freshwater station on the Shatt al Basrah Canal with salinities up to 3.5‰, Al-Daham and Yousif (1990) found this species to be the second most dominant after Liza subviridis, comprising 7.1% by number and 10.9% by weight. Al-Daham et al. (1993) found young fish in the Shatt al Basrah mostly from April to October. Cage-cultured fish are reared at 14-31°C in Kuwait Bay (Abou-Seedo et al., 2003). Temperatures in Kuwait Bay during spawning are 14-18ºC during the winter months, a situation mirrored by Liza klunzingeri but not other species which begin to spawn in April (Abou-Seedo and Dadzie, 2004).
Age and growth
A fast growing and hardy fish. Life in Iranian fresh waters has not been studied. A study of fish in the Shatt al Basrah canal, a man-made estuary of southern Iraq, was based on mostly small and immature fish (49-181 mm standard length) caught mostly in April-October. The length-weight relationship was W = 0.0511 L2.893, the dominant age group was 1+ fish, the maximum age was 3+ years, fish grew to 95, 155 and 215 mm total length in their first three years of life, and mortality (Z) was 2.23 (Al-Daham et al., 1993).
In an aquaculture experiment in Kuwait, fish more than doubled in weight over a 6 week period (Jafri et al., 1981). Males mature at a smaller size (12.3-14.2 cm) than females (24.3-26.2 cm) in cage-culture in Kuwait Bay (Abou-Seedo et al., 2003). However fish in the Shatt al Arab are usually less than 20 cm long and most are immature, in age groups 0 and 1. The length-weight relationship for both sexes was W = 0.0916 L2.6601. The lowest condition factors were found in April and May, possibly because fish were spent after spawning or were in lower condition after the winter (Hussain et al., 1987). In Kuwait, ages up to 14 years have been reported with ranges in von Bertalanffy growth parameters for the years 1981-1985 of L (cm) = 38.3-52.29, K = 0.169-0.298, and t0 -0.213- to -2.237. Total mortality values (Z) were 0.432-0.709, this range suggesting that, even for relatively large samples (92-314 fish), may be too small to provide reliable estimates of Z in species with a large overlap in age groups and where old fish are sampled only with difficulty. The length-weight relationship was total weight = 0.02874 x total length2.79198. Growth and mortality estimates based on all data were L∞ = 40.48 cm, K = 0.258, t0 = -0.965, tmax = 14 years and Z = 0.600 (Samuel and Mathews, 1987). Morgan (1985) gave values of L∞ = 43, K = 0.20 and Z = 0.97 but his study excluded fish over 30 cm and below 19 cm which accounts for the difference in mortality; and Samuel and Mathews (1987) had a value about 2.0 for Z when only fish 20-30 cm long were analysed.
Food
Freshwater food habits not known for Iran in detail but the one specimen examined contained plant fragments and scales of a cyprinid.
In a study of the recovering Hawr al Hammar, diet was 60% shrimps and 40% insects (Hussain et al., 2006). Feeds on echinoderms, worms, crustaceans, insects, bivalve molluscs and plants in the sea (Nasir, 2000; Al-Daham et al., 1993). Hussain et al. (1987) found crabs and bivalves to be the most important items by percentage in the Shatt al Arab Fish, shrimps and aquatic insects were also taken and there was significant seasonal variation, with shrimps and aquatic insects more important in December and spring. Hussain et al (1994) found bivalves in 91% of fish by number and weight in the Khawr az Zubayr. Al-Daham et al. (1993) found fish in the Shatt al Basrah fed on, in order of occurrence, crustaceans (decapods, amphipods, isopods, mysids, cladocerans and cyclopoids), fishes (Liza spp., Barbus luteus, Thryssa purava, eggs and scales), molluscs (Corbicula, Lymnaea, Tryonia and Sphaeriidae), algae (Oscillatoria, Syndera, Fragillaria and Cladophora), higher plants (Vallisneria, Ceratophyllum, seeds and roots) and aquatic insects (Corixidae, Hemiptera, Odonata and Coleoptera). Crustaceans were most important during July and November, molluscs in May and fishes during August. Hosseini (1998) examined food in coastal waters of Bushehr, Delvar and Rostami in the northern Persian Gulf of Iran and found 36.4% to contain crabs, 34.0% other fish and 13.4% shrimps. Snails and sea urchins were also eaten.
Reproduction
Al-Hassan et al. (1993) have shown for fish from the Shatt al Arab near Basrah, Iraq that haematological parameters vary with reproductive phase and between sexes. Cage-reared fish in Kuwait Bay have a prolonged spawning season from February to April. Fecundity there is up to 3,837,000 eggs. Spawning in the Shatt al Arab estuary is reported for April (Hussain and Ahmed, 1995) and Al-Daham et al. (1993) record a spawning season for the northwestern Arabian (= Persian) Gulf as January to April with a peak in February and March. Abu-Hakima (1984a) found the spawning period in Kuwait waters to be January to March with fecundity up to 2,152,993 eggs. This species is a protandrous hermaphrodite with males dominating in smaller size groups (22.3-24.2 cm) while females dominate in larger groups (24.3-26.2 cm) (Abou-Seedo et al., 2003). Samuel and Mathews (1987) give a spawning date of 1 December for their Kuwait sample. The gonadosomatic index was highest in February-March in Hosseini's (1998) study in coastal waters of the northern Persian Gulf.
The average absolute fecundity in coastal waters near Bushehr in Iran was 1,842,700, sex ratio was 1:1, and the spawning peak was January-February (Hossini and Savari, 2004).
Parasites and predators
None recorded.
Economic importance
A good food fish seen in bazaars along the Persian Gulf coast and in the Shatt al Arab. It was selling at U.S.$3.5-5.5 per kg in Kuwait about 1980, with 213 tons landed in 1995 for a value of U.S.$1,769,407 (Abou-Seedo et al., 2003). Experiments there indicate that this species can be farmed (Jafri et al., 1981; Abou-Seedo et al., 2003) and this has been proposed for Iranian waters in the Persian Gulf (Regunathan and Kitto, 2005). Experimental culture has been tried at Qeshm Island where a million larvae were produced in March with 100,000 larvae 2.0-3.5 cm long surviving in May (www.shilat.com, downloaded 7 June 2007). It is caught by trawls, handlines, in hadra (fixed stake nets) and gargoor (fish pots) and in the sport fishery in the Arabian (= Persian) Gulf (Samuel and Mathews, 1987; Carpenter et al., 1997).
Conservation
This marine species is fished commercially in the sea and populations there may be under some threat as a consequence. The status of freshwater populations is unclear as they appear quite rare and are presumably derived from marine populations at intervals.
Further work
The frequency of occurrence, detailed distribution and biology of this species in Iranian fresh waters needs study.
Sources
Iranian material: uncatalogued, 1, 62.9 mm standard length, Bushehr, about15 km above mouth in Helleh River (ca. 29º13'N, ca. 50º43'E).
Comparative material: BM(NH) 1974.2.22:1859, 1, 76.4 mm standard length, Iraq, Basrah (30º30'N, 47º47'E); BM(NH)1974.2.22:1858, 1, 76.3 mm standard length, Iraq, Beree (no other locality data).
© Brian W. Coad (www.briancoad.com)