Rutilus frisii (Nordmann 1840)

Can be diagnosed from its congeners in Black and Caspian Sea basins by having the following characters: body almost cylindrical, depth 19-26% SL; 53-64 + 3 scales on lateral line; abdomen posterior to pelvic rounded; snout rounded, stout; mouth subterminal; dorsal fin with 9-10½ branched rays; iris and fins grey or slightly yellowish; breeding males with large, scattered tubercles on top and side of head (Ref. 59043).

Lays eggs which adhere to rocks and gravel, rarely on submerged plants. Eggs hatch in 10-16 days at 12-19°C (Ref. 59043).

Dorsal soft rays (total): 11 - 12; Analsoft rays: 12 - 14

A semi-anadromous species which occurs in large brackish estuaries and their large, freshened plume waters, coastal lakes connected to rivers and lowland stretches of large rivers. Can tolerate salinities up to 7-12 ppt. Landlocked populations live in lakes or reservoirs. Larvae and early juveniles take zooplankton, algae and insect larvae as food while adults feed on molluscs, Rhithropanopeus crabs and other benthic invertebrates. Feeding ceases while migrating, spawning and overwintering. Breeds in small rivers or streams with heavy current on gravel bottom. Begins migration to rivers in second half of October (Black Sea, rarely in Caspian Sea). When rivers are covered with ice, spawning migration stops and continues when ice breaks up or even under ice in February-April. Spawns in April-May. Adults migrate back to estuaries to forage immediately after spawning. Juveniles move to estuaries during first summer in August. Landlocked populations undertake migration in springs from lakes or reservoirs or middle stretches of rivers to tributaries or upper reaches (Ref. 59043).

fisheries: commercial; aquaculture: commercial

Do not confuse it with another fish called the kutum, Rutilus kutum

Rutilus frisii, called the vyrezub, Black Sea roach, or kutum, is a species of fish in the family Cyprinidae, native to the basins of the Black Sea, Sea of Azov, and Sea of Marmara from the rivers of Bulgaria to western Transcaucasia and in Lake Iznik (Turkey).

The related Caspian Sea fish Rutilus kutum (also called kutum, Caspian kutum) has been treated as a subspecies of R. frisii (i.e. R. frisii kutum.), but the name kutum is applied to R. frisii itself in FishBase, referring to official names of FAO and AFS.