Bleak

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Bleak

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Cyprinidae
Genus:	Alburnus
Species:	A. alburnus

Binomial name

Alburnus alburnus
(Linnaeus, 1758)

The Bleak is a small pelagic fish of the Cyprinid family.

1 Description
2 Occurence
3 Ecology
- 3.1 Spawning
- 3.2 Importance
4 Particularities
5 References

[edit] 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 the fins are pointed and colourless. The mouth is turned upward. The maximum length is approximately 25 cm.

In Europe the species can easily be confused with many other species. In England young Bream and Silver Bream can be confused with young Bleak. 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.

[edit] Occurence

The Bleak occurs in Western England. In Europe it occurs in Southern Sweden, France and eastward toward the Wolga Basin and North-Western Turkey.

[edit] 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. The bleak prefers open waters and is found in large numbers where there is an inflow of food from pumping stations or behind weirs. It is also found in streams and also in clear standing waters and can be very numerous in lakes.

[edit] Spawning

The bleak spawns near the shore in shallow waters. The substrate is not important.

[edit] 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.

[edit] Particularities

The scales of the Bleak are used to make a silver pigment called the Essence Orientale and artificial pearls. In Sweden, the roe is used for a kind of caviar, löjrom.