Species Accounts - Bagridae
The bagrid catfishes are found in fresh waters of Africa and Asia. Some species attain 2 m in length. There are about 18 genera and about 170 species (Nelson, 2006). Only one species is known from Iran.
This family is characterised by a scaleless body; a depressed head and rounded to compressed elongate body; short dorsal fin with a strong, often serrated spine; a strong, serrated spine in the pectoral fin; a short to long adipose fin; anal fin short to long; caudal fin forked or deeply emarginate; a free margin to the gill membranes over the isthmus; the anterior and posterior nostrils are well separated; anterior nostrils tubular; mouth ventral and transverse or arched; 4 pairs of barbels with the nostril barbel on the posterior nostril, maxillary barbels can be very long, other barbels are mandibular and mental (chin); teeth on the prevomer, premaxillaries and mandible; and eyes often covered by skin. Maximum size is about 2 m.
These catfishes are generally nocturnal. Certain species are important food fishes and others are kept as pets in aquaria.
Genus Mystus
Scopoli, 1777
This is a catchall genus comprising numerous species in Asia. Roberts (1994) restricts the genus to 8 closely related species (see also Grant (2004)). Only 1 species is known from Southwest Asia including Iran. A history and usage of the name Mystus is given by Jayaram and Anuradha (1984).
This genus is characterised by an elongate body, rounded anteriorly and compressed posteriorly, a short and moderately depressed head, head smooth or rugose, an elongate cranial fontanelle extending posteriorly to the base of the occipital process and divided into anterior and posterior portions of nearly equal length by an epiphyseal bar (Roberts, 1994), small to moderate eyes set high and not visible from the ventral surface of the head, a free circular eyelid, a wide transverse, usually subterminal mouth, maxillary barbels very long, jaw teeth are in villiform patches, on the lower jaw as a curved or angular band interrupted at the mid-point, continuous and curved slightly in the upper jaw, total gill rakers 11-30, gill openings very wide and free from the isthmus, adipose fin high and very long, caudal fin deeply forked, upper caudal lobe often much larger than lower, 37-46 vertebrae about equally divided between abdominal and caudal ones, and branchiostegal rays 6-12.
Mystus pelusius
(Solander in Russell, 1794)
Common names
ابوزمير (abu-zummair or abu zumir, an Arabic name used in Khuzestan), mahi nish dor (an Abadani name, from www.abadan.net/abadanidictionary.html, downloaded 4 December 2003), sag mahi (= dog fish), گربه ماهي (= gorbeh mahi, meaning catfish), chamu.
[abu-zummair, abouz-zoumeir, abu-al-zamir, abu'l-zoumeir, zugzug in Aleppo, jahudi in Mosul, all in Arabic; Tigris mystus (Fricke et al., 2007)].
Systematics
Synonyms are Bagrus halepensis Valenciennes in Cuvier and Valenciennes, 1840 from the "Couiac, qui est la rivière d'Alep" (= Quwayq at Aleppo, Syria) (see Bailey (1951) on the publication date), Macrones aleppensis Günther, 1864, Macrones colvillii Günther, 1874 from "Bagdad", and Mystus misrai Anuradha, 1986 described from "Lake Antioche, Syria". Hypselobagrus Aleppensis is a new combination by Lortet (1883). Günther (1864) proposed Macrones aleppensis on page 75 but withdrew the name on page 431 when he realised the species was the Silurus pelusius of Solander.
No types of Silurus pelusius described from the "River Kowick" (= Quwayq) are known (Eschmeyer et al., 1996). A syntype of Macrones aleppensis, 127.8 mm standard length, from the "R. Coic, Aleppo, Syria" is in the Natural History Museum, London (BM(NH) 1955.6.25:1). Six syntypes of Macrones colvillii are also in London, ca. 175-234 mm standard length, from "R. Tigris nr. Baghdad" collected by Colville (BM(NH) 1874.4.28:6-8, 1875.1.14:19-21; Roberts (1994) agrees with my observations although Eschmeyer et al. (1996) give BM(NH) 1875.1.14:19-20 for the latter, i.e. 2 fish only).
The holotype of Mystus misrai is in the Muséum d'Histoire Naturelle, Geneva under MHNG 603.95, measuring 123.1 mm standard length, with 1 paratype under MHNG 2231.84 measuring 117.6 mm standard length, 1 paratype in the Zoological Survey of India, Calcutta under FF2315 and 1 specimen missing (Eschmeyer et al., 1996).
Roberts (1994) indicates that more material should be examined to compare fish with short barbels, weakly serrate dorsal spine, short adipose fin and a highland distribution (= pelusius) while the contrasting fish are colvillii.
Key characters
The 4 pairs of barbels, a strong spine in both the dorsal and pectoral fins, elongate and strong adipose fin are distinctive. The head tapers but is not as flattened as in Heteropneustes fossilis, and the mouth is subterminal.
Morphology
The dorsal fin spine is smooth on most of the outer edge and rough on the inner edge. Serrae can be weakly developed or absent, or may be well developed. The dorsal fin spine has 1-4 serrae or notches at the anterior tip and 5-9 along the rear margin, apparently not related to fish size. The pectoral spine is stronger than the dorsal spine and is serrated with 14-23 antrorse teeth on the inner margin, the number increasing with size. The maxillary barbel extends back to the pectoral fin origin or, rarely, as far as beyond the anal fin.
Dorsal fin with 1-2 spines and 7-8, usually 7, branched rays, anal fin with 6-10 branched rays, pectoral fin with 1 spine and 7-9 branched rays and the pelvic fin with 5-6, usually 5, branched rays. Al-Hassan and Hassan (1993) have shown asymmetry in pectoral ray and gill raker counts in samples of this species from the Shatt al Arab, Iraq, possibly due to environmental stress. Total gill rakers 10-18 (Roberts (1994) gives 12(1), 13(7), 14(11), 15(11), 16(8), 17(4) and 18(1), reaching the second raker or further when appressed. Total vertebrae 42-46 (Roberts (1994) gives 42(10), 43(16), 44(3), 45(2) and 46(5). The gut has a large stomach followed by an intestine with about 4 loops.
In specimens examined by me dorsal fin with 2(11) spines and 6(1) or 7(10) branched rays, anal fin with rays difficult to separate into branched and unbranched (perhaps 4-6 unbranched and 6-10 branched rays), pectoral fin with 1(11) spine and 7(3), 8(5), 9(2) branched rays and the pelvic fin with 5(11) branched rays. Total gill rakers 12(1), 13(2), 14(2), 16(2). One specimen with only 7 gill rakers, was possibly abnormal. Total vertebrae 42(1), 43(1), 44(2) and 45(1).
Sexual dimorphism
Unknown.
Colour
Pale brown to olivaceous overall with fins and belly lighter, on a predominant dark silver. Some fish may be silvery-grey overall when fresh. A dark shoulder spot is present. There may be a black spot at the base of the dorsal fin. The dorsal and anal fins have melanophores on the rays and membranes and so are darker than the other fins. The margin of the adipose fin is narrowly black. The caudal fin has a black margin. There may be 3 (sometimes 2), narrow, white stripes on the flank, one along and one each above and below the lateral line. The stripe below the dorsal and adipose fins is narrower than the others. Barbels are whitish, somewhat darker dorsally. Peritoneum silvery to light brown. Jayaram and Sanyal (2003) report an albino specimen from Baghdad.
Size
Reaches 171.2 mm standard length or 22.9 cm total length (Günther, 1874) but possibly to 30 cm total length (Firouz, 2005).
Distribution
Found in the Orontes, Quwayq, and Tigris-Euphrates basins. In Iran this fish is found in the lower reaches of rivers in the Tigris River basin of Iran, including the Jarrahi, and also the Zohreh River of the northern Gulf basin (Abdoli, 2000). Also recorded from Fars near Darab in the Rudbal River drainage which flows to the Straits of Hormuz, possibly an accidental introduction, although Esmaeili and Coad (2005) point out that there is no evidence of fish introductions from Khuzestan to Fars. It may simply be very rare outside the Tigris-Euphrates basin in Iran.
Zoogeography
Jayaram and Sanyal (2003) consider that Mystus is derived from an African Bagrus-like ancestor and the genus spread from west to east.
Habitat
Niazi (1976) observed this species in rivers, marshes and brackish waters in Iraq although summer kill resulted from very low water levels and increased salinity.
Age and growth
Al-Hassan et al. (1991) aged this species using eye lenses and vertebrae for a population from the Qarmat Ali River north of Basrah, Iraq. Fish up to 20 cm total length were examined and three age groups were determined, with considerable overlap of lengths for each group. Al-Shami (1998) however found 7 age groups (0+-6+) for the same river using vertebrae to age fish 54-223 mm total length. The highest growth was found in the first year and no significant differences were found between males and females in growth rate. The L∞ was 225.75 mm and the length-weight relationship log W = -4.7516 + 2.8173 log L. The relative condition ranged from 0.94 in December to 1.22 in May.
Food
Roberts (1994) found eggs in the branchial chamber and stomach apparently identical with those from the ovary. Other stomach items were fish fin pieces and cyprinid fish scales. Aquatic insects, crustaceans, detritus and plant remains are also found in stomach contents of fish examined by me. Al-Shami (1998) found mean feeding activity and intensity in the Qarmat Ali River, Iraq to be higher in spring and summer, declining in autumn and winter. This fish was carnivorous, taking mainly crustaceans but also insects, fishes, molluscs and aquatic plants. Hussein and Al-Shami (2001) also reported that fish in the Garma Canal, Iraq had a diet dominated by crustaceans (the isopod Sphaeroma annandalei, amphipods, the decapod Elamenopsis kempi, and the prawns Metapenaeus affinis and Atyaephyra desmaresti), followed by aquatic insects (chironomids, corixids and dytiscids), fish (Alburnus sp. and Aphanius dispar), molluscs (the gastropod Lymnaea tenera euphratica) and aquatic plants. Feeding occurred year round with a peak in May and a lowest value in November. Al-Shamma'a (2005) found shrimp and insects to form 47% by volume of the diet of this fish at Al-Fuhoud, Hawr al Hammar, Iraq.
Reproduction
The Qarmat Akli River fish attained maturity in the first year of life with the smallest mature male 92 mm long and the smallest female 72 mm. Eggs were laid in May and June with a fecundity range of 1156-25,833 eggs for fish 105-180 mm total length and 11.88-49.29 g in weight. Relative fecundity was 97.3-524.1 eggs/g (Al-Shami, 1998).
Parasites and predators
None reported.
Economic importance
This species is of no economic importance. Anglers may catch it on hook and line in Khuzestan but, being scaleless, it is not eaten.
Conservation
This species appears to be relatively common, although not often caught in large numbers, and its conservation status has not been assessed.
Further work
See under Systematics.
Sources
Description also based on Anuradha and Jayaram (1985) and Anuradha (1986).
Type material: See above under Macrones aleppensis (BM(NH) 1955.6.25:1) and Macrones colvillii (BM(NH) 1874.4.28:6-8, 1875.1.14:19-21).
Iranian material:- CMNFI 1979-0087, 1, 162.2 mm standard length, Khuzestan, Karun River at Ahvaz (31º19'N, 48º42'E); CMNFI 1979-0368, 1, 75.6 mm standard length, Khuzestan, Karkheh River (32<º24'30"N, 48º09'E); CMNFI 1991-0153, 1, 123.3 mm standard length, Khuzestan, Zohreh River (no other locality data); CMNFI 1993-0133, 1, 152.6 mm standard length, Khuzestan (no other locality data); BM(NH) 1905.10.14:57, 1, 140.1 mm standard length, Bushehr, Jarrahi River 140 miles northwest of Bushehr (no other locality data); ZMH 2524, 1, 137.1 mm standard length, Kermanshah, Karasu-Gamasiab-Seymarreh (no other locality data); ZMH 4339, 2, 100.5-100.6 mm standard length, Khuzestan, Karun River (no other locality data); uncatalogued material, 1, 57.7 mm standard length, Fars, Cheshmeh Golabi, 15 km west of Darab (28º47'N, 54º22'E)(Esmaeili and Coad, 2005).
Comparative material:- CMNFI 1980-1036, 2, 161.0-167.8 mm standard length, Turkey, Elazig, Keban Dam near Elazig (38º41'N, 39º14'E); CMNFI 1987-0017, 1, 156.8 mm standard length, Iraq, Hawr al Hammar (no other locality data); BM(NH) 1912.5.2:7, 1, 172.5 m standard length, Iraq, Shatt al Arab (no other locality data); BM(NH) 1920.3.5:5-6, 2, 95.4-101.0 mm standard length, Iraq, Basra (30º30'N, 47º47'E); BM(NH) 1936.3.10:3, 1, 56.1 mm standard length, Iraq, Euphrates River at Nasiriyah (31º02'N, 46º16'E); BM(NH) 1974.2.22:1781-2, 1, 52.3 mm standard length, Iraq, Khalis (33º49'N, 44º32'E); BM(NH) 1974.2.22:1783-4, 1, 31.0 mm standard length, Iraq, Khalis (33º49'N, 44º32'E); BM(NH) 1975.5.16:6, 1, 155.2 mm standard length, Turkey, Elazig, Euphrates River, Keban Dam Lake (no other locality data).
© Brian W. Coad (www.briancoad.com)