Species Accounts - Gobiidae - Chasar

Revised:  18 July 2009

Genus Chasar
Vasil'eva, 1996

This genus has a single species in the Caspian Sea. The characters of the genus are covered in more detail by Miller in Miller (2004) and are the characters of the species below. It is recognised as distinct from the related Neogobius by head sensory papillae patterns (especially an additional transverse row before row b) and modally 7 first dorsal fin rays rather than 6. The number of the transverse suborbital neuromast rows of the cephalic lateral line system is an important diagnostic feature for the monotypic genus Chasar according to Miller (2004). Pinchuk and Ragimov (1985) count these rows consecutively from anterior to posterior as 1 – 8 while Miller (2004) postulates an additional transverse row anterior to the longitudinal suborbital row b labelling the posteriormost row as row 7 (Pinchuk et al. in Miller, 2004). A Farsi common name for Neogobius and related gobies is گاو ماهي (gav mahi).

Chasar bathybius
(Kessler, 1877)

Common names

[bychok-glubokovodny or deepwater goby]

Systematics

Described from Svinoi Island south of Baku, Azerbaijan. No types known.

Key characters

Nape with cycloid scales anteriorly, not quite reaching orbit level, head depth at eyes about equal or slightly less than width between upper origins of opercles, interorbital distance equal to or slightly less than orbit, angle of jaw below pupil of eye, snout longer than eye, up to 1.8 times orbit diameter, upper lip not swollen at angle, pelvic fin not reaching anal fin, except in young, anterior pelvic fin membrane without well-developed lateral lobes, caudal peduncle depth 0.3-0.5 length, first dorsal fin with 7 rays and little higher than second dorsal fin (which is lower posteriorly), overall colour semi-transparent, and lateral series scales mostly 55-60.

Morphology

First dorsal fin with 6-8 spines, usually 7, second dorsal fin with 1 spine and 14-16 soft rays, and anal fin with 1 spine and 11-14 soft rays, lateral series scales 55-65. Scales are overall ctenoid but cycloid on the nape, breast, opercle, abdomen and and lobe of the pectoral fin. The pectoral fin is long reaching back well beyond the level of the second dorsal fin origin. Lateral line system usually with eight or nine transversal suborbital neuromast rows, two rows ventral to the longitudinal suborbital row b. Four neuromast rows on the opercle. Lateral line system with eight suborbital neuromast rows arranged transversally, five before, three above and two below the longitudinal row b. Four rows of free neuromasts on the opercle instead of the characteristic three rows of all other neogobiines.

Meristics for Iranian specimens: first dorsal fin with 6(1), 7(14) or 8(1) spines, second dorsal fin with 14(4), 15(9) or 16(3) soft rays, anal fin with 11(3), 12(9) or 13(4) soft rays, pectoral fin with 18(10) or 19(6) rays, scales in lateral series 55(1), 56(3), 57(6), 59(1) or 60(1), and transverse rows of scales 16(8) or 17(4).

Sexual dimorphism

Males grow larger than females.

Colour

The body is semi-transparent with reddish or yellowish-brown colour. The myotomes are visible but scales are difficult to see. The back is darker than the flank and belly. Preserved fish have 4 faint saddles and faint spots along the lateral midline, the first dorsal fin has two brownish bands, and young have a stripe-like spot posteriorly on the first dorsal fin.

Size

Attains 29.0 cm.

Distribution

Caspian Sea basin, recorded between Kultuk and Astara in Azerbaijan (Ragimov, 1965). Kiabi et al. (1999) report this species from the southeast Caspian Sea, southwest Caspian Sea and south-central Caspian Sea in Iran. Miller in Miller (2004) maps this species from the Safid River westwards and from Gorgan Bay but there are no text records to go with the map. Recently recorded from Iran (Ahnelt, et al., 2007). South coast of the Caspian Sea especially in Gorgan Bay (Jolodar and Abdoli, 2004).

Zoogeography

Endemic to the Caspian Sea but related to the speciose genus Neogobius.

Habitat

A marine species, not entering fresh waters, found down to 75 m and perhaps deeper, especially in colder conditions. It is found on sandy and shelly bottoms and in smaller numbers on firm silt.

Age and growth

Life span is estimated to be 4 years, with maturity in the second year and spawning every year.

Food

Fish are an important food for larger specimens, smaller fish take crustaceans. Fish food includes Knipowitschia iljini and crustaceans include the decapod Palaemon, corophiids, mysids and some gammarids. A small number of worms (Nereis) are also eaten.

Reproduction

Eggs of only one size have been found in this species, suggesting a single spawning each year. Up to 2979 eggs have been recorded with a maximum diameter of 2.6 mm. Spawning in the southern part of the Middle Caspian Sea takes place from the second half of June until July. Males approach the coast in the first half of March or April while females remain at 20-30 m. Females enter shallow water in late April and in greater numbers in May and June. After spawning, fish retreat to areas deeper than 10-15 m.

Parasites and predators

Eaten by sturgeons and the Caspian seal. Sattari et al. (2004; 2005) surveyed this species in the inshore area of the Caspian Sea, recording Anisakis sp. and Dichelyne minutus.

Economic importance

None in Iran but caught in Lenkoran, Azerbaijan with fixed nets and in northern Azerbaijan with cast nets. The fish are oily but pleasant tasting (Pinchuk et al. in Miller, 2004).

Conservation

Kiabi et al. (1999) consider this species to be data deficient in the south Caspian Sea basin according to IUCN criteria. Criteria include medium numbers, medium range (25-75% of water bodies), absent in other water bodies in Iran, and absent outside the Caspian Sea basin.

Further work

The distribution of this species in Iranian waters needs clarifictaion.

Sources

Based on Pinchuk et al. in Miller (2004) and Ahnelt et al. (2007).

Iranian material: CMNFI 1971-0352, 8, 141.7-195.8 mm standard length, Gilan, Caspian Sea + Shalman River (37°28’N, 49°27'E, 37°08’N, 50°15’E); CMNFI 2006-0022, 3, 142.9-195.4 mm standard length, Gilan, southwest Caspian Sea off Astara (38°00’N, 49°30’E to 38°20’N, 50°00'E); CMNFI 2006-0023, 1, 99. 4 mm standard length, Gilan, Chaboksar (36°58’N, 50°34’E); CMNFI 2006-0024, 2, 160.4-183.1 mm standard length, Gilan, Talesh (37°48’N, 48°55’E); CMNFI 2006-0025, 2, 174.7-187.9 mm standard length, Gilan, Talesh (37°48’N, 48°55’E); CMNFI 2006-0026, 2, 76.7-81.3 mm standard length, Gilan, southwest Caspian Sea off Bandar Kiashahr (37°25’N, 49°57’E).

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© Brian W. Coad (www.briancoad.com)