The houting (''Coregonus oxyrhynchus'') is a European, allegedly

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of whitefish in the family

Salmonidae Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefis ...

. It is native to the estuaries and rivers draining to the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

. The houting is distinguishable from other ''

Coregonus ''Coregonus'' is a diverse genus of fish in the salmon family (Salmonidae). The ''Coregonus'' species are known as whitefishes. The genus contains at least 68 described extant taxa, but the true number of species is a matter of debate. The type ...

'' taxa by having a long, pointed snout, an inferior mouth and a different number of

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 ...

s.Freyhof, J. and C. Schöter. 2005. The houting Coregonus oxyrinchus (L.)(Salmoniformes: Coregonidae), a globally extinct species from the North Sea basin. Journal of Fish Biology 67:3, 713–729.Schöter C., 2002. Revision der Schnäpel und Großen Maränen des Nordseeund südwestlichen Ostseeraumes (Teleostei: Coregonidae). Diplomarbeit, Rheinischen Friedrich-Wilhelms-Universität, Bonn. The houting once occurred in

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

, the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

and

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

.Freyhof, J. & Kottelat, M. 2008. Coregonus oxyrinchus. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. . Downloaded on 21 December 2008.

Controversial status

There is however controversy whether whitefish surviving in the southeastern North Sea sector of

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Danish Realm, Kingdom of Denmark ...

(

Wadden Sea The Wadden Sea ( nl, Waddenzee ; german: Wattenmeer; nds, Wattensee or ; da, Vadehavet; fy, Waadsee, longname=yes; frr, di Heef) is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern conti ...

) and considered there as houting (Danish: ''snæbel'') represent the same species as the houting that was

extirpated Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...

from the more southwestern parts of the North Sea.Hansen M.M., Fraser D.J., Als T.D. & Mensberg K.L.D.(2008)
Reproductive isolation, evolutionary distinctiveness and setting conservation priorities: The case of a European lake whitefish and the endangered North Sea houting (''Coregonus'' spp.)
BMC Evolutionary Biology 8:137 doi:10.1186/14716-2. Like the more southwestern population, the Danish North Sea population has a long, pointed snout and an inferior mouth, and it is

anadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...

, spending most of its adult life in coastal waters, but migrating into rivers to breed (some other European ''Coregonus'' occur in

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

water, but the ability to live long-term in full salt water is unique to the houting).Møller, P.R.; and H. Carl, editors (2012). Atlas over danske ferskvandsfisk tlas of Danish Freshwater Fish

Natural History Museum of Denmark The Natural History Museum of Denmark ( da, Statens Naturhistoriske Museum) is a natural history museum located in Copenhagen, Denmark. It was created as a 1 January 2004 merger of Copenhagen's Zoological Museum, Geological Museum, Botanical Muse ...

. The Danish houting is genetically part of the widespread ''

Coregonus lavaretus ''Coregonus lavaretus'' is a species of freshwater whitefish, in the family Salmonidae. It is the type species of its genus ''Coregonus''. There are widely different concepts about the delimitation of the species ''Coregonus lavaretus'' and abou ...

complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

(including ''

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 ...

'' of the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and from ...

basin; some prefer to include the Danish houting in this species), while its genetic relationship to the extinct population cannot be confirmed due to a lack of sufficient samples of the latter.Jacobsen M.W.; Hansen M.M.; Orlando L.; Bekkevold D.; Bernatchez L.; Willerslev E.; and Gilbert M.T. (2012). Mitogenome sequencing reveals shallow evolutionary histories and recent divergence time between morphologically and ecologically distinct European whitefish (Coregonus spp.). Mol Ecol. 21(11): 2727-2742. Nevertheless, there are some minor differences in the genetics of the Danish houting compared to other living members in the ''C. lavaretus'' complex, as well as the differences in morphology and ecology, making it an

evolutionarily significant unit An evolutionarily significant unit (ESU) is a population of organisms that is considered distinct for purposes of conservation. Delineating ESUs is important when considering conservation action. This term can apply to any species, subspecies, geo ...

.Dierking, J.; L. Phelps; K. Præbel; G. Ramm; E. Prigge; J. Borcherding; M. Brunke; and C. Eizaguirre (2014). Anthropogenic hybridization between endangered migratory and commercially harvested stationary whitefish taxa (Coregonus spp.). Evol Appl. 7(9): 1068-1083. Hybridization and

introgression Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Intr ...

between North Sea houting and its relatives is well-documented, and likely the result of translocations of ''Coregonus'' between different regions by humans. Some researchers argue that the morphological differences between different houting populations are not exceptional within the broader variation of the European whitefish, and probably no species-level extinction has taken place. The primary reason for treating the Danish houting and the extinct houting as separate are differences in the number of gill rakers (on average, the Danish has fewer than the extinct), but this number can vary extensively in ''Coregonus'', even within a single population and species,Christensen, G.H. (2010). Danmarks ferskvandsfisk enmark's Freshwater Fish pp. 47–48. and genetic studies of ''Coregonus'' have shown that gill rakers are of limited use in predicting relationship among populations. Some think that the morphological differences in number of gill rakers are sufficient for treating them as separate, and that the last true houting was caught in the lower

Rhine ), Surselva, Graubünden, Switzerland , source1_coordinates= , source1_elevation = , source2 = Rein Posteriur/Hinterrhein , source2_location = Paradies Glacier, Graubünden, Switzerland , source2_coordinates= , so ...

in 1940. Studies in the early 2000s (decade) indicated that there was no overlap in the possible number of gill rakers of the two (28–35 in the Danish; 38–46 in the extinct), but later reviews have shown that there is an overlap (up to 41 has been found in the

Elbe The Elbe (; cs, Labe ; nds, Ilv or ''Elv''; Upper and dsb, Łobjo) is one of the major rivers of Central Europe. It rises in the Giant Mountains of the northern Czech Republic before traversing much of Bohemia (western half of the Czech Repu ...

, a reintroduced population based on Danish houting).Ramm, G.; and J. Dierking (2014). . Geomar, Helmholtz Centre for Ocean Research Kiel. A €13 million restoration project of the Danish houting, partly funded by the European Union's LIFE programme and the Danish Natural Agency, was undertaken in 2005–2013, and there is ongoing monitoring of the species and regulation of the fish-eating

great cormorant The great cormorant (''Phalacrocorax carbo''), known as the black shag in New Zealand and formerly also known as the great black cormorant across the Northern Hemisphere, the black cormorant in Australia, and the large cormorant in India, is a w ...

from important locations.Svendsen, J.C.; A.K.O. Alstrup; and L.F. Jensen (11 April 2018)
Save a North Sea fish from becoming museum piece.
Nature. Retrieved 12 April 2018. As of 2019, a total of more than €20 million has been used on its conservation, with almost two-thirds funded by Denmark and the remaining by the European Union.Mandrup, L., and N.M. Jørgensen (26 April 2019)
Efter redningsaktioner for 150 mio. kr.: Danmarks mest sjældne fisk er i lille fremgang.
fter rescue projects for 150 million DKK: The population of Denmark's rarest fish is slowly increasing DR News. Retrieved 26 April 2019. However, the only remaining fully natural and significant population of Danish houting is in the

Vidå The Vidå (german: Wiedau, North Frisian ''Widuu'') is a creek in The Jutland region of, Denmark. The creek starts east of Tønder and flows to the west, ending in the North Sea. In places the Vidå marks the border between Denmark and Germany (' ...

River, estimated in 2014 to consist of about 3,500 adults. Little is known about its exact spawning and juvenile requirements, and despite the earlier project it was still declining, leading to fears that it could become fully extinct unless more is done to preserve it. After years with a downward trend in its numbers, an increase to about 4,000 adult Danish houtings was registered in 2018–19, with most individuals in the Vidå and fewer in (both populations increasing). Individuals from the Danish population have been used as a basis for re-establishing houting in the

Eider Eiders () are large seaducks in the genus ''Somateria''. The three extant species all breed in the cooler latitudes of the Northern Hemisphere. The down feathers of eider ducks, and some other ducks and geese, are used to fill pillows and quilt ...

, Elbe (both indisputably a natural part of the range) and Rhine (arguably non-native, if the extinct is recognized as a separate species).Borcherding, J.; A. W. Breukelaar; H. V. Winter; and U. König (2014). Spawning migration and larval drift of anadromous North Sea houting (Coregonus oxyrinchus) in the River IJssel, the Netherlands. Ecology of Freshwater Fish 23(2): 161–170.

References

{{Authority control Coregonus Extinct animals of Europe Extinct animals in the United Kingdom Fish described in 1758 Taxa named by Carl Linnaeus Taxonomy articles created by Polbot Taxobox binomials not recognized by IUCN