Huchen

Danube salmon ( Hucho hucho )

The Danube salmon ( Hucho hucho ), and Danube salmon or Rotfisch, but also called Donauzalm ', inhabited the grayling and barbel region of rivers, especially the Danube River and many of its tributaries. The Danube salmon is also a food fish, but it is rare and critically endangered. For this reason he was chosen in 2012 by the Austrian Society for Nature Conservation to the fish of the year.

From Central and East Asia more Hucho species have been described ( Hucho taimen, Hucho ishikawae, Hucho Hucho bleekeri and perryi ). The latter kind of Sakhalin taimen or Japanese Danube salmon is also provided as Parahucho perryi in its own monotypic genus.

Features

The average of these fish is 110-130 cm long with a weight of 10-30 kg. As heaviest ever caught Danube salmon specimens from the Danube at Tulln in Lower Austria are of 60 kg in the 1890s. One of the hardest Danube salmon caught in recent years had a weight of 35 kg at 137 cm length ( caught with a Huchenzopf in the Drava barrage Kellersberg ).

The Danube salmon has an elongated, almost circular in cross-section body. On the red-brown back, numerous dark spots are in the shape of an X or a half-moon.

Way of life

This is the largest ever living in fresh water salmon fish spawns in April, the water must then have a temperature of 6-9 ° C. Before spawning the Danube salmon takes a walk against the flow of the river. The female lays in a pit in the gravel bed of the river, into which it then spawns the eggs. The clutch size is about 1000 pieces per kg body weight. 30-35 days after the male has fertilized the eggs, the larvae hatch.

Smaller fish feed on larvae of aquatic insects or fallen into the water insects, the larger specimens are predators and hunt mainly fish, but also other small vertebrates such as mice floating in the water or ducklings. Danube salmon hold on, especially in deep pools.

Economic Importance

The Danube salmon breeding is of great importance, since the natural propagation of the species conservation is sufficient only in very few waters. To this end, the parents are captured shortly before spawning, or they are kept in special tanks. If the brood has reached a size of 4-10 cm, it is exposed to at appropriate places.

Hazardous situation

The World Conservation Union IUCN provides the Danube salmon in the Red List of endangered species and rated him as endangered ( Endangered ). The reasons for this are embankments and straightening, increasing water pollution, traffic jams, destroy the spawning grounds and juvenile habitat, and weirs without fish ladders, which obstruct the Danube salmon the way to its spawning grounds. The destruction of spawning sites by gravel mining in the river beds carry the stocks too bad.