Common bleak

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Bleak
AlburnusAlburnus1.JPG
Conservation status
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 (Alburnus alburnus) is a small freshwater coarse fish of the cyprinid family.

Description[edit]

Alburnus.jpg

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[edit]

The bleak occurs in Europe and Western Asia: north of the Caucasus, Pyrenees and Alps, and eastward toward the Volga basin and North-Western Turkey. It is absent from the major southern peninsulas and most of British Isles except southeast England. It is however locally introduced in Spain, Portugal, and Italy.

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

Ecology[edit]

The bleak 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[edit]

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

Importance[edit]

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

Uses[edit]

Bleak are used as bait for sport-fishing for larger fish. Previously, guanine was extracted from the scales of the bleak and used in making artificial pearls.

References[edit]