The huchen (Hucho hucho) (, from German), also known as Danube salmon or redfish (), is a large species of freshwater fish in the family Salmonidae native to the Danube basin in Central and Eastern Europe. It is the type species of genus Hucho (a.k.a. the taimens), being closely related (in the same subfamily) to salmon, trout, char and lenoks.
Distribution
The huchen is endemic to the Danube basin in Europe where the remaining population is threatened primarily by river damming, resulting in habitat fragmentation and loss through river impoundment and disruption of the longitudinal continuity of rivers, cutting away fish from its spawning grounds, with overfishing and fisheries mismanagement as an additional issue in many areas. Damming and all these other problems are especially visible in the Balkans.
It has been introduced to other major river basins elsewhere on the continent and even North Africa, to rivers in Morocco, but these populations are not self-sustaining.
Ecology
Appearance
The huchen reaches about in length and more than in weight. The average length is between . 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, but most distinctive feature is its head, which is larger than in other salmonides (longer and wider), with large elongated mouth.
Diet
As the largest fish found within many European rivers, Huchen like many other salmonoids under an ontogenetic change as they grow older. Smaller fish feed on the larvae of water insects or on insects dropped into the water. As they get older, larger individuals prey on other species of fish and small vertebrates.
Common nase is the most important food source for a Danube salmon (huchen). From a study in Slovakia, older angler caught individuals primarily seemed to prey on spirlin Alburnoides bipunctatus, chub Leuciscus cephalus, brown trout Salmo trutta, and barbel Barbus barbus. also one weighing , which is stuffed and was kept in a fish-farm in Austria for breeding.
Other stories of record specimens with existing photographs and media reports include , caught in January 1938 by Bosnian railway worker and angler Halil Sofradžija at the Dragojevića Rapids on the Drina river, near the town of Ustikolina in Bosnia and Herzegovina. This case was recorded on photograph and reportage was later published in prime Serbian daily Politika on 23 February 1938. Dževat Šarkinović, an environmental protection advisor caught a Danube salmon illegally with a net weighing , long, in Lake Plav 1985, and gave it to Hotel "Plavsko jezero" who presented it at International Fair of Hunting and Fishing in Novi Sad where it was noted as a "world record". Today, this specimen stands as stuffed exhibit at the wall of hotel's foyer in Plav. Another recorded trophy from the Drina include huchen caught by angler Remzija Krkalić from Foča in 1940, weighing . Larvae hatch 30 to 35 days after fertilization.
Commercial breeding
thumb|upright=.50|right|A large [[Inn (river)|Inn River huchen (1913)]]
There is a considerable effort to produce huchen fry commercially and to reintroduce the species into the wild with moderate to good success. This requires catching the adults just before spawning and keeping them in special tanks. Fry are released in appropriate places once they have reached .