| White-eye bream | |
|---|---|
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Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cypriniformes |
| Family: | Leuciscidae |
| Subfamily: | Leuciscinae |
| Genus: | Ballerus |
| Species: | B. sapa |
| Binomial name | |
| Ballerus sapa (Pallas, 1814) | |
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| The range of the species | |
| Synonyms[2] | |
White-eye bream (Ballerus sapa) is a species of freshwater ray-finned fish belonging to the family Leuciscidae, which includes the daces, minnows and related fishes. This species is indigenous to Europe and Western Asia in the rivers draining into theBlack,Azov,Caspian andAral Seas, although it isinvasive elsewhere.
The white-eye bream was first formallydescribed in 1814 by the Germanzoologist,botanist andnatural historianPeter Simon Pallas with itstype locality given as theVolga River and its tributaries.[2] In 1843Johann Jakob Heckel proposed themonospecific genusBallerus withCyprinus ballerus as its only species.[3] This species is now classified withinBallerus, this genus belongs to thesubfamilyLeuciscinae of the family Leucicsidae.[2]
The white-eye bream is classified within the genusBallerus, a name which Heckel usedtautonymously fromCyprinus ballerus,ballerus being derived from the Greek wordbaléros, the ancient name for thezope (B. ballerus) first written down byAristotle. Thespecific namesapa which is a common name for this species in Russian.[4]
The white-eye bream is distinguished from the zope by its small and inferior mouth, having between 47 and 54 scales on thelateral line and in having a large eye which has a diameter that is roughly equal to the length of the snout. The maximum publishedtotal length of 35 cm (14 in), although 15 cm (5.9 in) is more typical.[5]
The white eyed bream is native to central and eastern Europe and western Asia in rivers that drain into the Black, Azov, Caspian and Aral Seas. It has been introduced toLake Ladoga, the northern part of theDvina system, theRhine and some of the rivers draining into theBaltic Sea. It has invaded theVistula river system byLessepsian migration through theDnieper–Bug Canal. This species occurs in large fast flowing lowland rivers and estuaries. The eastern, brackish populations enter the lower reach of rivers for spawning.[1]
The white-eyed bream feeds on benthic invertebrates. They attain sexual maturity at 3 or 4 years of age. The inland subpopulations spawn from April to May, requiring the water temperatures to be greater than 8 °C (46 °F). They spawn in large aggregations in fast-flowing water, depsoting eggs on gravel substrates or among submerged vegetation. Estuarine subpopulations feed in brackish water migrate upstream to fresh water in late autumn.[1]
