Pink salmon

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Pink salmon
Male pink salmon at spawning time

Male pink salmon at spawning time

Systematics
Overcohort : Clupeocephala
Cohort : Euteleosteomorpha
Order : Salmonid fish (Salmoniformes)
Family : Salmon fish (Salmonidae)
Genre : Pacific salmon ( Oncorhynchus )
Type : Pink salmon
Scientific name
Oncorhynchus gorbuscha
( Walbaum , 1792)

The pink salmon ( Oncorhynchus gorbuscha ) is a species of fish from the genus Oncorhynchus . Its name comes from its extremely high hump which the sexually mature male fish get at spawning time .

features

Migration of pink salmon during spawning time ( Indian River , Sitka , Alaska)
Pink salmon in its freshwater life

The pink salmon reaches an average length of 40 to 50 centimeters, but can reach a maximum length of 65 centimeters. He has a stocky and more or less high-backed body. Compared to other salmon species, it is characterized by very small scales, with 143 to 240 scales running along the side line . The head is relatively pointed with a very large gap in the mouth that extends behind the eyes. The base of the tail is very narrow. The humpback salmon are silvery, with a blue to greenish back and black oval dots on the back and on the entire caudal fin. The flanks have a more or less pronounced red sheen.

The pelvic fins are ventral and have 10 to 11 fin rays. The undivided dorsal fin has 12 to 16, the very long anal fin 14 to 20 soft fin rays. On the first gill arches there are usually 28 spines.

The name is derived from the high hump that forms between the head and the dorsal fin of the sexually mature males ( Milchner ) during the mating season. The dairy farmer is also brightly pink during the mating season and forms a clear spawning hook on the jaw. The spawning hook is formed by an extension and curvature of the upper and lower jaw, with the lower jaw in particular growing and forming a hook-shaped extension. The teeth are replaced by new teeth that have no function; together with the deformation, food intake is no longer possible.

Way of life

The pink salmon live in salt water and only switch to fresh water at spawning time. From the end of June to the middle of October, the mature fish ascend into the running waters of their homeland. Induced by the fresh water, the males already undergo the typical physical changes (hump, spawning hook, discoloration) after a week, which can be traced back to a change in the hormonal balance. The strong changes are related to the rival fights taking place among the male fish at the spawning grounds. The changes are irreversible and the animals die shortly after the spawning season.

Often the humpback salmon spawn in the estuary area or in the lower reaches of their home waters. The fry hatch after about 90 to 125 days in winter and then stay in fresh water for some time before swimming to the sea. There, the young pink salmon initially stay close to the coast and feed on plankton. After a while they move further out into the sea. After two years, the animals are sexually mature and return to their home waters to spawn there.

The juvenile fish eat insect larvae and small crustaceans, in the sea they eat fish and crabs.

Occurrence

The original distribution area extends over the coastal parts of the North Pacific and the rivers from Alaska to California ( Mackenzie River to Sacramento River ) and in Russia from the Lena to Peter the Great Bay . It also occurs in the rivers of the Aleutian , Kuril , Sakhalin , Commander Islands , as well as on Hokkaidō and northern Hondo . From 1939 he was also settled in Russia in the tributaries to the White Sea and in the Northwest Atlantic on the American east coast ( Labrador Peninsula ). On the coast of Norway to Scotland, the species is known as an occasional stray visitor.

Systematics

The pink salmon is one of 14 species of the genus Oncorhynchus , which also includes important food fish such as the rainbow trout ( O. mykiss ) and the ketal salmon ( O. keta ).

supporting documents

literature

  • Roland Gerstmeier, Thomas Romig: The freshwater fish of Europe. For nature lovers and anglers. Kosmos, Stuttgart 1998, ISBN 3-440-07068-9 , pp. 177-178.

Web links

Commons : Oncorhynchus gorbuscha  - collection of images, videos and audio files