FISHES OF THE FAMILY CYPRINIDAE IN THE WATER BODIES OF UKRAINE - V. V. Zamorov - 2015

GENUS PSEUDORASBORA — PSEUDORASBORA BLEEKER

Mouth superior, transverse, very small. Barbels absent. Lower jaw turned upward, transverse, with a sharp edge, slightly projecting over the upper jaw, without a tubercle. Pharyngeal Teeth uniserial, laterally compressed. Scales large, 30-38 in the lateral line. Throat covered with scales. Lateral line straight, running along the middle of the body. Gill rakers rudimentary. Dorsal fin short, with 7 (8) branched rays, without a spine. Belly without a keel. Lower lip thin, not interrupted at the symphysis. Over three species are known in Japan, China, and the Amur basin. One species has been introduced into the Water bodies of Ukraine.

Stone moroko (chebachok amursky) — Pseudorasbora parva (Temminck et Schlegel)

Morphological features: D III 7 (8); A III 6; P I 11-12 (13); VI (6) 7; Squ (31, 33) 34-38 (39); l. l. (30) 31-37 (38); Squ₁ 5 (6); Squ₂ 3-4; vert. 31-34 (35, 36); sp. br. (6, 8) 9-13 (14-16); d. f5-5 (98.7%), 6-5 (1.3%). Length up to 11 cm, body weight of the largest specimen 15 g, lifespan about 5 years (Fig. 44).

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Fig. 44. Stone moroko Pseudorasbora parva

Body moderately elongate, slightly compressed laterally, relatively low. Its maximum body depth averages (in adult fish) 24-26% of standard length. Dorsal profile convex, with a noticeable hump starting behind the nape; ventral profile slightly convex or even straight. Back and belly generally rounded, sometimes the back is slightly laterally compressed in front of the dorsal fin. Dorsal fin high, straight-cut, generally rounded at the upper and lower margins; anal fin slightly rounded, almost straight. Paired and caudal fins rounded, the latter with a fairly deep notch, both lobes nearly equal in length. Pelvic fins originate beneath the first or second branched ray of the dorsal fin and almost reach the anus. The first hard ray in the dorsal and anal fins is barely noticeable, very short. Pectoral fins long, almost reaching the Base of the pelvic fins. An elongated scale is present on the outer side at the base of the pelvic fins. A similar scale is sometimes found at the base of the anal fin. Scales large, transversely elongated. Lateral line complete, straight, running along the middle of the sides, incomplete in juveniles. HEAD slightly flattened dorsoventrally, especially in the anterior part, relatively small, equal in length to the caudal fin. Snout long, averaging almost one-third of the head length. Mouth very small, superior, semi-lunar, appearing as a transverse slit in its upper part. Its apex is at the level of the middle or upper third of the eye. Eyes small. Forehead flat, wide, averaging more than 1/3 of the head length. Gill rakers short, nearly rudimentary. Pharyngeal teeth weak, smooth, laterally compressed, with a small hook at the tip, arranged in a single row. Abdominal cavity silvery white.

Introduced species. Along with other Amur species (silver carp, grass carp), it was brought to Ukraine in the 1960s, successfully naturalized, and has become a part of the ichthyofauna in the basins of the Dniester, Danube, Southern Bug, Dnieper, rivers of the Northern Azov region, Crimean water bodies, and numerous enclosed fish-rearing ponds.