View source for Common bleak

{{Short description|Species of fish}}
{{More citations needed|date=March 2025}}
{{Speciesbox
|status=LC
|status_system=IUCN3.1
|status_ref=<ref name=IUCN>{{cite iucn |author=Ford, M. |year=2024 |title=''Alburnus alburnus'' |page=e.T789A135064432 |doi=10.2305/IUCN.UK.2024-2.RLTS.T789A135064432.en |access-date=26 March 2025}}</ref> 
|image=AlburnusAlburnus1.JPG
|taxon=Alburnus alburnus
|display_parents = 3
|authority=([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]])
|synonyms = {{Specieslist
| Cyprinus alburnus | Linnaeus, 1758
| Leuciscus alburnus | (Linnaeus 1758)
| Aspius ochrodon | [[Leopold Fitzinger|Fitzinger]], 1832 
| Aspius alburnoides | [[Edmond de Sélys Longchamps|Selys-longchamps]], 1842
| Alburnus lucidus | [[Johann Jakob Heckel|Heckel]], 1843
| Alburnus strigio | [[Charles Lucien Bonaparte|Bonaparte]], 1845
| Alburnus avola | Bonaparte, 1846
| Alburnus breviceps | Heckel & [[Rudolf Kner|Kner]], 1857 
| Alburnus fracchia | Heckel & Kner, 1857
| Alburnus lucidus var. lacustris | Heckel & Kner, 1857
| Alburnus scoranzoides | Heckel & Kner, 1857 
| Alburnus lucidus var. angustior | [[Antoni Bazyli Wałecki|Walecki]], 1863
| Alburnus lucidus var. latior | Walecki, 1863 
| Alburnus alborella var. lateristriga | [[Giovanni Canestrini|Canestrini]], 1864
| Alburnus fabraei | [[Charles Émile Blanchard|Blanchard]], 1866
| Alburnus mirandella | Blanchard, 1866
| Alburnus lucidus var. colobocephala | [[Victor Fatio|Fatio]], 1882
| Alburnus lucidus var. elata | Fatio, 1882
| Alburnus lucidus var. elongata | Fatio, 1882
| Alburnus lucidus var. oxycephala | Fatio, 1882
| Leuciscus lucidus var. ilmenensis | [[Nikolai Arkadewich Warpachowski|Warpachowski]], 1886
| Alburnus striatus | [[V. V. Petrov (ichthyologist)|Petrov]], 1926
| Alburnus alburnus strumicae | [[Stanko Karaman|Karaman]], 1955
}}
| synonyms_ref = <ref name = "Cof genus">{{Cof genus|genus=Alburnus|access-date=26 March 2025}}</ref>
}}

The  '''bleak''' or '''common bleak''' ('''''Alburnus alburnus''''') is a small freshwater [[coarse fish]] of the [[family (biology)|family]] [[Leuciscidae]], which includes the minnows, daces and bleaks.<ref name=EB1911>{{cite EB1911|wstitle=Bleak|volume=4|page=55}}</ref> The common bleak is found in Europe and Western Asia.

== Description ==
[[Image:Alburnus.jpg|250px|left|thumb]]
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 18–23 fin rays. The [[lateral line]] is complete. The bleak has a shiny silvery colour, and the [[fin]]s are pointed and colourless. Its maximum length is about 25&nbsp;cm (10&nbsp;in).

In Europe, the bleak can easily be confused with many other species. In [[England]], young [[common bream]] and [[Blicca bjoerkna|silver bream]] can be confused with young bleak, though the pointed, upward-turned mouth of the bleak is already distinctive at young stages. Young [[Rutilus rutilus|roach]] and [[ruffe]] have wider bodies and  short anal fins.

==Occurrence==
The bleak occurs in [[Europe]] and Western Asia: north of the [[Caucasus]], [[Pyrenees]], and [[Alps]], and eastward toward the [[Volga]] basin in [[northern Iran]] and north-western [[Turkey]]. It is absent from [[Iberian Peninsula|Iberian]] and [[Italian Peninsula|Apennine]] peninsulas, from the rivers of [[Adriatic Sea|Adriatic]] watershed on the [[Balkans]] and most of British Isles except southeast England. It is  locally introduced in [[Spain]], [[Portugal]], and [[Italy]], though.
[[Image:AlburnusAlburnusHead.JPG|250px|thumb| The shiny and pearly colours on the head of a bleak in direct sunlight]]

==Ecology==
The bleak lives in great schools and feeds upon small [[mollusc]]s, insects that fall in the water, insect [[larva]]e, [[worm]]s, small [[shellfish]], and [[detritus|plant detritus]]. It is found in [[stream]]s and [[lake]]s. The bleak prefers open waters and is found in large numbers where  an inflow of food from pumping stations or behind weirs occurs.

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

=== Reproduction ===
Source:<ref>Billouttes.eu : [https://billouttes.eu/freshwater-fish/panfish/panfish-the-common-bleak-alburnus-alburnus Panfish: Common Bleak (Alburnus alburnus)]</ref>

The Common Bleak typically reaches sexual maturity at around three years of age. Its spawning period takes place from April to June when the water temperature ranges between 14 and 15&nbsp;°C (approximately 58&nbsp;°F).

During this time, a female Common Bleak can lay between 5,000 and 7,000 eggs in multiple batches. These eggs are deposited on submerged vegetation or shallow areas of the water. Males undergo changes during the spawning season, developing [[nuptial tubercles]] on their backs and flanks, while their fins take on an orange hue. The incubation period for the eggs lasts about 2 to 3 weeks.

The growth rate of the young fish, known as fry, is relatively slow, and their primary source of nutrition is plankton. It is also possible for hybridization to occur between the Common Bleak and other cyprinid fish species, such as [[Chub]], Roach, [[Scardinius|Rudd]], or [[Bream]].

=== Importance ===
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 ==
Bleak are used as bait for sport-fishing for larger fish. In 1656 in Paris, a Mr. Jaquin extracted from the scales of the common bleak, so-called ''essence Orientale''<ref name=EB1911/> or "pearl essence",<ref>Johann Rudolf von Wagner, Ferdinand Fischer, and L. Gautier, ''Traité de chimie industrielle'' (Treatise on industrial chemistry), 4th ed., (Paris, France:  Masson & Co., 1903), vol. 2, [https://books.google.com/books?id=K2mhGDwiSJsC&pg=PA64 pp. 64–65.]</ref> (used in making [[Imitation pearl|artificial pearls]]), which is crystalline [[guanine]].<ref>In 1861, French chemist [[Charles-Louis Barreswil]] (1817–1870) found that "pearl essence" was guanine.  See:  Barreswil (1861) [http://gallica.bnf.fr/ark:/12148/bpt6k3010v/f246.item.zoom "Sur le blanc d'ablette qui sert à la fabrication des perles fausses"] (On the white of ablette that's used in making imitation pearls), ''Comptes rendus'', '''53''' :  246.</ref>

== References ==
{{Commons category|Alburnus alburnus}}
{{Reflist}}
*{{ITIS |id=163663 |taxon=Alburnus alburnus |accessdate=24 January 2006}}
*{{FishBase|genus=Alburnus|species=alburnus|year=2005|month=10}}

{{Taxonbar|from=Q200473}}

[[Category:Alburnus]]
[[Category:Freshwater fish of Europe]]
[[Category:Fish of Europe]]
[[Category:Fish described in 1758]]
[[Category:Taxa named by Carl Linnaeus]]