Alburnus chalcoides (Guldenstadt, 1772)

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 314

Alburnus chalcoides

Common name. Caspian Shemaya.

Diagnosis. Distinguished from other species of Alburnus in Caspian basins by: ○ 52–70+2–5 lateral line scales / ○ usually 8½ branched dorsal rays / ○ 12–17½ branched anal rays / ○ ventral keel between posterior pelvic base and anus present and well developed / ○ 18–22 gill rakers / ○ anal origin ½–2½ scales behind dorsal base, below dorsal ray 7–8 in some individuals / ○ ventral keel exposed for 3–12 scales in front of anus / ○ a faint, dark-brown mid-lateral stripe. Size up to 400 mm SL, resident fish in rivers or streams usually much smaller.

Distribution . Aral and Caspian basins, mostly western to southern coast, rarely in Ural and Volga.

Habitat. Lower parts of larger streams, rivers, lakes, estuaries, and brackish sea areas. Lives near surface, tolerating salinities up to 14 ‰. Migrates long distances upstream from sea or lakes to headwaters of streams in foothills and montane regions. Spawns in small rivers or streams with strong currents on submerged vegetation or gravel bottoms. Lacustrine and reservoir populations spawn in tributaries.

Biology. Semi-anadromous, riverine, and lacustrine populations. First spawn at 2–4 years, females 1 year later than males. Anadromous populations enter rivers in autumn (September in Kura) and migrate upstream in winter and/or spring. Spawns May–September in water 0.2–0.7 m deep, current about 1 m /s and 18–26°C, often with much splashing. Males appear to be territorial. They congregate at spawning sites and wait for mature females, which arrive later. Eggs stick to pebbles or stones. Embryonic development lasts 2–3 days; larvae initially remain between pebbles for 8–11 days, then actively migrate to shallower areas and backwaters. Many populations are riverine. In migratory populations, adults return to sea, lakes or estuaries soon after spawning to feed. Young juveniles migrate downstream in autumn of same year or following spring. Larvae and juveniles feed on zooplankton, algae, and insect larvae, adults mainly on planktonic crustaceans, terrestrial insects, and small fish. Often hybridises with sympatric Squalius species.

Conservation status. LC.

Further reading. Kazancheyev 1981 (Caspian); Movchan & Smirnov 1983 (morphology, biology); Kottelat & Freyhof 2007 (distribution, biology, diversity Europe); Coad 2021a (biology, morphology).

Figures

Alburnus chalcoides

Distribution