Chondrostoma colchicum, Derjugin, 1899

Chondrostoma colchicum View in CoL View Figure

Common name. Colchic nase.

Diagnosis. Distinguished from other species of Chondrostoma in Aegean, Marmara, and Black Sea basins by: ○ 55−69, usually 58−64, total lateral-line scales / ○ 6–6 or 6–5, pharyngeal teeth / ○ 8−10½, usually 9½, branched dorsal rays / ○ 8−11½, usually 9½, branched anal rays / ○ 20−30 gill rakers / usually 9, rarely 8, branched pelvic rays / ○ thick cornified sheath covering lower lip. Size up to 300 mm SL.

Distribution View Figure . Türkiye: Sakarya east to Çoruh ( Türkiye and Georgia) and Black Sea basin from Çoruh north to Novorossiysk ( Georgia and Russia).

Habitat. Moderate to fast-flowing, large- to medium-sized rivers with rocky or gravel bottoms, also in lakes and reservoirs. Spawns in fast-flowing water on shallow gravel beds, often in small tributaries.

Biology. Matures at 3 years. Spawning season depends on altitude and water temperature, peaking in April at 12–15°C. Females lay 2–3 batches of eggs during a spawning season. Feeds on periphyton scraped from hard substrate.

Conservation status. LC.

Remarks. Chondrostoma angorense from Sakarya is a synonym, and C. colchicum is very closely related to C. nasus , both may be conspecific.

Further reading. Derjugin 1899 (description); Berg 1949b (morphology); Elanidze 1983 (morphology, biology); Elvira 1987 (description); Tarkan et al. 2007 (distribution); İlhan & Balık 2008 (distribution); Bayçelebi et al. 2015 (distribution); Güçlü et al. 2018 (morphology); Çiftçi et al. 2020 (phylogeny); Küçük et al. 2023 (synonymy of Chondrostoma angorense ).