Houting
Drawing of Nordseeschnäpels
The houting (Coregonus oxyrinchus ), also referred to as Rheinschnäpel Small and sulfuric Brenke, is an extinct species of fish in the family Salmonidae, which belonged to the species of whitefish, whitefish or whitefish (Coregonus ). Is also traditionally referred to as houting a population in Danish North Sea area as well as resettlement in the Rhine and Elbgebiet - but these fish actually belong to a different species Coregonus maraena.
Features
The houting had an elongated and laterally flattened body. He reached an average body length of up to 30 to 50 inches with a maximum length of about 90 inches and a maximum weight of 2,000 grams. The snout was prolonged nose-like in migratory forms. The dorsal coloration was gray to olive green, the flanks and belly silvery, with sometimes a reddish sheen was present. On the first gill arch 38 to 46 rakers were trained in this kind, which he was distinguished from other species of the genus.
The dorsal fin had 3 hard and 8-9 soft rays, the third and longest rigid beam was ossified and serrated at the rear. The pelvic fins were throat constantly, so lay in front of the pectoral fins, and consisted of two hard and 8 soft rays and the paired pectoral fins had 2 hard - and 15 to 17 soft rays. Like all whitefish possessed the houting an adipose fin.
Dissemination
The houting marin lived in the coastal area of the Baltic and North Sea and on the Atlantic coasts of the British Isles and Scandinavia. He was also in the brackish water found in rivers and lakes in the catchment area of the Baltic and North Sea and the Alps. There were both inpatient populations in lakes as well as migratory (anadromous ) populations that migrated from the sea into the rivers.
Today, the houting applies throughout its former range area to be extinct, with the population in Denmark, which has been described as the last remaining population, as well as new settlements in the Rhine basin to another type, Coregonus maraena belong.
Way of life
The fish were schooling fish of the open water area ( pelagic zone ) and fed on plankton and invertebrate benthic organisms. The reproduction and oviposition took place in freshwater, the marine populations rose up in the rivers and spawned there in the shore area on hard ground.
Endangering
In particular, the migratory and marine populations were very severely threatened because their migrations to the spawning grounds were interrupted by locks and dams that can not overcome the fish. Due to water pollution, the fish are very sensitive to the, also many of the original spawning habitats were destroyed.
In the Red List of Threatened Species IUCN the houting is listed as " extinct ", as has been documented since 1940, no evidence for the occurrence of the species in its native range.