Common Bleak

Common Bleak
Conservation status
Least Concern (IUCN 2.3)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Cyprinidae
Genus:	Alburnus
Species:	A. alburnus
Binomial name
Alburnus alburnus (Linnaeus, 1758)

The common bleak is a small pelagic fish of the Cyprinid family. It is often referred to simply as a "bleak", though this term can refer to any species of Alburnus.

Description

The body of the bleak is elongated and flat. The head is pointed and the relatively small mouth is turned upwards. The anal fin is long and has 18 to 23 fin rays. The lateral line is complete. The bleak has a shiny silvery colour; and the fins are pointed and colourless. The maximum length is approximately 25 cm.

In Europe the bleak can easily be confused with many other species. In England, young bream and silver bream can be confused with young bleak, though the pointed upward turned mouth of the bleak is already distinctive at young stages. Young roach and ruffe have a wider body and a short anal fin.

Occurrence

The bleak occurs in Europe: in Western England, Southern Sweden, France and eastward toward the Volga Basin and North-Western Turkey.

Ecology

It lives in great schools and feeds upon small molluscs, insects that fall in the water, insect larvae, worms, small shellfish and plant detritus. It is found in streams and lakes. The bleak prefers open waters and is found in large numbers where there is an inflow of food from pumping stations or behind weirs.

Spawning

The bleak spawns near the shore in shallow waters. Some are found in deep water. The substrate is not important.

Importance

The bleak is an important food source for predatory fish. It is more sensitive to pollution then other cyprinids, which might explain the decline in North-Western Europe.

Uses

Bleak are eaten and are used as bait for sport-fishing for larger fish. Guanine is extracted from the scales of the bleak and is used in making artificial pearls.

The shiny and pearly colors on the head of a bleak in direct sunlight

References

• "Alburnus alburnus". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=163663. Retrieved 24 January 2006. 
• Froese, Rainer, and Daniel Pauly, eds. (2005). "Alburnus alburnus" in FishBase. 10 2005 version.
•  This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.