Comprehensive DescriptionRead full entry
BiologyInhabits from premontane to lowland reaches of clear, warm, medium sized to large rivers with fast current and gravel bottom. Occasionally found in lakes. Frequently overwinters in large group, inactive or active in slow-flowing river habitats. Adults often form shoal, hiding under overhanging trees or bridges during the day. Adults are encountered most active during dusk and dawn while larvae and juveniles are active during both day and night. Larvae and juvenile stay on the bottom in very shallow shoreline habitats and leave the shores for faster-flowing waters as they grow (Ref. 59043). Lives in the deeper, faster-flowing upper reaches of rivers with stony or gravel bottom (barbel zones). Feeds chiefly on benthic invertebrates, such as small crustaceans, insect larvae, mollusks, mayfly and midge larvae (Ref. 6258) and also on small fish and sometimes algae (Ref. 59043). Spawns usually in very shallow, fast-flowing riffles (Ref. 59043). Spawning occurs from May to July after the fish have migrated upriver (Ref. 556). Eggs are poisonous (Refs. 4537, 6258). Locally threatened due to water pollution and river regulation, especially in Baltic drainages, Elbe, South Bug and Dniepr, and heavily impacted by pollution in central Europe but recovering. Population has declined sharply due to construction of large reservoirs and pollution during 20th century and has stabilized at a moderate level since then (Ref. 59043).