''Coregonus widegreni'', also called the Valaam whitefish, is a putative species of

freshwater whitefish The freshwater whitefish are fishes of the subfamily Coregoninae, which contains whitefishes (both freshwater and anadromous) and ciscoes, and is one of three subfamilies in the salmon family Salmonidae. Apart from the subfamily Coregoninae, th ...

, a part of the common whitefish complex (''Coregonus lavaretus'' sensu lato) from Northern Europe. It is a demersal form of freshwater whitefish that feeds on benthic invertebrates. It spawns in late autumn, and can reach a length of 55 cm maximum. It is characterized by a low

gill raker Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the ...

density. In the strict sense the name ''C. widegreni'' refers to a population of whitefish that inhabits relatively deep waters (50–150 m) of Lake Ladoga in Northwest Russia.Freyhof J, Kottelat M (2008
''Coregonus widegreni''
The IUCN Red List of Threatened Species, 2016 version. More often the range is thought to comprise coastal areas of the Baltic Sea (except southern section of the Swedish coast) and several larger lakes in Sweden (e.g.

Vänern Vänern ( , also , ) is the largest lake in Sweden, the largest lake in the European Union and the third-largest lake of all Europe after Ladoga and Onega in Russia. It is located in the provinces of Västergötland, Dalsland, and Värmland i ...

Vättern Vättern ( , ) is the second largest lake by surface area in Sweden, after Vänern, and the sixth largest lake in Europe. It is a long, finger-shaped body of fresh water in south central Sweden, to the southeast of Vänern, pointing at the tip ...

) and Northwest Russia ( Onega). It is one of several types of whitefish co-distributed in Northern Europe and exhibiting different breeding and feeding habits. In the Northern Baltic, ''C. avaretuswidegreni'' has referred to bottom-feeding whitefish that spawn in the sea ("lesser sparsely-rakered whitefish", in contrast to migratory anadromous whitefish referred to as ''C. lavaretus lavaretus''.Säisä, M., Rönn, J., Aho, T., Björklund, M., Pasanen, P. and Koljonen, M.-L. (2008
Genetic differentiation among European whitefish ecotypes based on microsatellite data.
''Hereditas '' 145, 68-83. doi:10.1111/j.0018-0661.2008.02050.x In contemporary Nordic usage, ''C. widegreni'' is not recognised as a distinct species, but at most as an

ecotype In evolutionary ecology, an ecotype,Greek: ''οίκος'' = home and ''τύπος'' = type, coined by Göte Turesson in 1922 sometimes called ecospecies, describes a genetically distinct geographic variety, population, or race within a specie ...

morphotype In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the s ...

of '' Coregonus lavaretus''Siika (''Coregonus lavaretus'')
Luke Natural Resources Institute Finland or of ''

Coregonus maraena ''Coregonus maraena'', referred to in English as the maraene, maraena whitefish or the whitefish, is a whitefish of the family Salmonidae that occurs in the Baltic Sea basin - in the sea itself and the inflowing rivers, and in several lakes as ...

''.Morfotyp: ''Coregonus maraena'' morphotype ''widegreni'' - sandsik
Dyntaxa Svensk taxonomisk databas (Sweden)

References

widegreni Fish described in 1863 Freshwater fish of Europe {{Salmoniformes-stub