Ctenopharyngodon idella (Cuvier and Valenciennes, 1844)

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 425-427

Ctenopharyngodon idella

Common name. Grass carp.

Diagnosis. Distinguished from similar Mylopharyngodon piceus by: ● body olive to brassy green on back, silvery white to yellow on flank / ○ body cylindrical / ● pharyngeal teeth laterally compressed, serrated, with a groove along grinding surface ( Figure 43), usually in two rows, 2,5–4,2. Size up to 1200 mm SL and 32 kg.

of the Caspian Sea. Subsequently, it was introduced to the Euphrates and Tigris drainages, where it is expanding its range. Ctenopharyngodon , Mylopharyngodon , and Hypophthalmichthys have been stocked throughout West Asia and are typically sourced from European suppliers. However, these activities have declined due to the perceived inferiority of the flesh of these species and their subsequent low market value. There is no documented evidence of any established population of these species in West Asia. Nevertheless, their potential to become established in the future as a consequence of warming due to climate change cannot be discounted. Further reading. Howes 1981 (anatomy); Chen 1987 (phylogeny); Cunha et al. 2002 (genetics); Kottelat & Freyhof 2007 (summary of distribution and biology); DeVaney et al. 2009 (invasion potential).

Distribution. Rarely introduced for weed control or escaped from aquaculture facilities. No established populations in West Asia. Native to East Asia, in most major Pacific drainages from Amur to Xi Jiang. Used in aquaculture in Asia, Europe, and North America; released in most major drainages. Established non-native populations in North America and in Aral Sea basin (Central Asia).

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https://doi. org/10.1515/9783111677811-019

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Habitat. Stocked in large rivers and almost all still waters spend cold season in deep places in lower reaches. Larvae such as lakes, reservoirs, and ponds. Often escapes from fish settle in flooded lakes and channels with little or no current farms. In its native range, inhabits rivers with pronounced after a downstream migration of about 1000 km. Larvae water level fluctuations caused by floods. Spawning and feed on phyto- and zooplankton and then, from about 25 overwintering in middle and lower reaches of large rivers. to 50 mm SL, on aquatic macrophytes. Larger juveniles In lakes, reservoirs, and backwaters during feeding season, and adults feed mainly on macrophytes, including terrespreferably in warm, clear water with high oxygen concen- trial macrophytes, during summer floods. Does not feed trations. in winter. There are reliable data on natural spawning in Biology. In natural habitat, first spawns at 7–10 years and rivers in southern Russia, but success of these reproductive about 600–800 mm SL, females 1–2 years later than males. events is not known.

Spawns April–August. Migrates upstream and spawns Conservation status. Non-native; stocked for commercial during high water, in upper water layer, or on surface in fisheries. In West Asia very rarely stocked. Native stocks in sections with strong currents. Females lay one or more por- eastern Russia and China are declining. Its introduction into tions of eggs depending on length of flood. Average females Czech Republic was accompanied by introduction of tapelay about 1.5 million pelagic eggs, hatching while drifting worm Bothriocephalus gowkongensis , which subsequently downstream in 2–3 days; if river is blocked or available caused severe losses in Cyprinus carpio farmed stocks.

river reaches are too short, eggs cannot drift long enough Further reading. Bíró 1999a (biology); Nico et al. 2001 and fail to develop. After spawning, adults leave river and (comparison with Mylopharyngodon ); Kottelat & Freyhof migrate to flooded areas, lakes, or backwaters with dense 2007 (summary of distribution and biology).

vegetation. They return to river in autumn–winter and

Hemiculter leucisculus ; Sirvan drainage, Iraq; ~ 90 mm SL.

Hemiculter leucisculus Habitat. Streams and rivers, reservoirs and lakes. Also in Common name. Sharpbelly. coastal lagoons in Caspian Sea.

Diagnosis. Distinguished from superficially similar Biology. Lives up to 6 years in Iran, begins spawning in species of Alburnus by: ● sharp keel on ventral midline second year. Spawns March–August, most likely fractional from chest to pelvic base / ● last unbranched dorsal ray spawners. Feeds on algae, plant material, terrestrial and unsegmented, stiff and spinous with flexible tip / ○ anal aquatic invertebrates, and small fish.

origin far behind vertical of last dorsal ray / ○ lateral line Conservation status. Non-native; introduced as a weed curves downward from its origin to end of pectoral fin. with stocked Common carp ( Cyprinus carpio ) or/and Size up to 200 mm SL. Chinese carps ( Ctenopharyngodon, Hyophthalmichthys ).

Distribution. Non-native to southern Caspian basin in Remarks. An invasive species introduced with Chinese carp Iran, Azerbaijan, and southern Russia. Locally introduced from Central Asia, invading the Caspian and Tigris basins. in Tigris drainage. Native from Amur in Russia, south Could appear wherever carp are stocked as it is transported to China, North and South Korea, Japan, and northern long distances with carp fingerlings. The current source of Vietnam. this species appears to be Caspian hatcheries in Azerbaijan and Iran. Still, it is only a matter of time before it becomes established in hatcheries producing Cyprinus carpio elsewhere. This species will invade all of West Asia, Europe, and North Africa, following the path of Pseudorasbora parva . Several species are confused under this name. The identity of the species introduced in the Western Palaearctic has yet to be investigated.

Further reading. Coad 2010a (biology, distribution); Vasil’eva et al. 2022 (East Asian diversity).