Author: (Linnaeus, 1758)
FBname: Asp
Comments: Occur in open water of large and medium-sized lowland rivers and large lakes (Ref. 59043).  Adults inhabit lower reaches of rivers and estuaries (Ref. 30578).  Prefer to stay near bridge pillars, near tributaries, under weirs, in deep currents and overgrown parts of river and in quiet bays of river bends (Ref. 9696).  One of the rare cyprinids which is piscivore; also prey on small aquatic birds.  Juveniles are gregarious predators while adults hunt in small groups or are solitary.  Juveniles and adults feed mainly on fish, especially on <i>Alburnus alburnus</i> or <i>Osmerus eperlanus</i> (Ref. 59043).  Migrate upstream in tributaries for spawning in April-June (Ref. 556, 30578).  Spawn in fast-flowing water on gravel or submerged vegetation.  Lake populations migrate to tributaries; semi-anadromous populations or individuals (Terek) forage mainly in estuaries and freshened parts of the sea, migrating to rivers only for spawning.  Begins spawning migration in second half of October (Terek) and overwinters in the lower reaches of river.  Hybridizes with <i>Leuciscus idus</i>.  Threatened due to alteration of river morphology (Ref. 59043).