Huchen

Huchen
Conservation status
Endangered  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Salmoniformes
Family:	Salmonidae
Subfamily:	Salmoninae
Genus:	Hucho
Species:	H. hucho
Binomial name
Hucho hucho (Linnaeus, 1758)

The huchen /ˈhuːkən/ or Danube salmon (Hucho hucho) is a large species of freshwater fish in the salmon family of order Salmoniformes. It is the type species of its genus.^[2] The huchen is endemic to the Danube basin in Europe where the remaining population is threatened by overfishing and habitat loss.^[1] It has been introduced elsewhere on the continent and in Morocco, but most of these populations are not self-sustaining.^[1] In historic times the huchen has also been found in the Dniestr basin. Sometimes it lives in big dam reservoirs on mountain rivers such as Lake Czorsztyn in Poland.^[3]

Appearance and behaviour

The huchen reaches about 1.5 m (4 ft 11 in) in length and more than 50 kg (110 lb) in weight.^[4] The average length is about 60 to 120 centimetres (24 to 47 in). The huchen has a slender body that is nearly round in cross-section. On the reddish brown back are several dark patches in an X or crescent shape. Smaller fish feed on the larvae of water insects or on insects dropped into the water; the larger individuals are predators of other species of fish and other small vertebrates such as mice crossing rivers.

The largest huchen catch on modern record weighed 34.8 kg (77 lb), caught in February 1985 in Spittal an der Drau in Austria,^[5] although older records report weights in excess of 60 kg (130 lb).^[6]

Reproduction

This largest permanent freshwater salmonid spawns in April, once water reaches a temperature of 6 to 9 °C (43 to 48 °F). For spawning, the huchen migrates up the river, where females excavate depressions in the gravel into which they deposit their eggs, then a male releases a cloud of sperm and the female then covers the eggs with sand.^[7] Larvae hatch 30 to 35 days after fertilization.

Commercial breeding

There is a considerable commercial effort to produce huchen fry to reintroduce the species into the wild. This requires catching the adults just before spawning and keeping them in special tanks. Fry are released in appropriate places once they have reached 4 to 10 cm (1.6 to 3.9 in).

References

Salmon
Groups and species	Salmon Salmonidae Adriatic salmon Atlantic salmon Black Sea salmon Pacific salmon Chum salmon Chinook salmon Coho salmon Masu salmon Pink salmon Steelhead Sockeye salmon Taiwanese salmon Danube salmon Sabertooth salmon Genetically modified salmon
Fisheries and management	Aquaculture of salmon Fly fishing bibliography Environmental issues with salmon Old McKenzie Fish Hatchery Pre-spawn mortality in coho salmon Puget Sound salmon Putcher Putcher fishing Alaska salmon fishery Salmon conservation Salmon run June hogs
As food	Salmon as food Cured salmon Gravlax Lohikeitto Lomi salmon Lox Rui-be Salmon burger Salmon cannery Salmon tartare Smoked salmon Images
Diseases and parasites	Diseases and parasites in salmon Amoebic gill disease Ceratomyxa shasta Gyrodactylus salaris Henneguya zschokkei Infectious salmon anemia virus M74 syndrome Myxobolus cerebralis Nanophyetus salmincola Salmon louse Sea louse Salmon tapeworm Sphaerothecum destruens Tetracapsuloides bryosalmonae
Organisations	Atlantic Salmon Federation Cook Inlet Aquaculture Association North Atlantic Salmon Conservation Organization Pacific Salmon Commission Welsh Salmon and Trout Angling Association Wild Salmon Center Yakima Klickitat Fisheries Project
Other	Ceasg H. Forman and Son (salmon smokehouse) Salmon (color) Salmon of Knowledge Salmon Fishing in the Yemen The Salmon Fly