Oncorhynchus masou formosanus

Taiwanese masu salmon ( Oncorhynchus masou formosanus )

The Taiwanese masu salmon ( Oncorhynchus masou formosanus ) is a rare, endemic in Taiwan subspecies of salmon species Oncorhynchus masou. The name Masu is Japanese and means " trout ".

Features

The Taiwanese masu salmon can grow up to 30 centimeters long. The base color is a dark turquoise, the silver belly color. Along the sides of the body are 9 vertical oval patches of dark color and 11 to 13 smaller black dots. During the mating period, the body pages of the males color dark red. The muzzle is broad and extends to below the eye; its shape is reminiscent of a hook, hence the scientific name genus Oncorhynchus, as well as the Chinese name of the fish (literally " hook mouth salmon " ) stir.

Dissemination

The Taiwanese masu salmon is an endemic to Taiwan Art He is a pure freshwater fish, found very rarely and only in a few rivers in the Taiwanese high mountain range, especially in the river Qijiawan ( Taichung). Like most salmon also requires the Taiwanese masu salmon a temperate climate (water temperature around 16 ° C ) in order to survive. In predominantly subtropical Taiwan, he is therefore to be found only at altitudes of about 1500 m, where a temperate climate.

The sooner numerous salmon is now almost extinct due to water pollution and due to the application of dams which impede its hiking trails and a nature reserve. Further difficulties in maintaining the masu salmon result from the imported from abroad rainbow trout ( Oncorhynchus mykiss ), which exceeds the masu salmon in size and robustness and has displaced him from parts of its habitat.

For about 30 years, the salmon are bred in kennels, exposed in several mountain rivers with success. In 1997, the territory of the Qijiawan River was declared a " sanctuary for the Taiwanese Masulachs ". At present, a slight increase of the populations can be observed. Because of its uniqueness, the salmon in Taiwan is called the "National Treasure ". As such, the animal also adorns the 2000 dollar bill Taiwan.

Way of life

Before the Ice Age, the Taiwanese salmon migrated even as other salmon species between their spawning grounds in the river headwaters and the sea back and forth. This way of life changed when the ground and temperatures in Taiwan transformed after the Ice Age. For a disabled now steep, rugged mountains, the trails of salmon, on the other hand forced the warming climate to the salmon, the levels and thus to avoid the estuaries into the sea. As a result of this development, the Taiwanese masu salmon to a pure freshwater fish that migrates to the sea was no more.

Masu salmon feed on aquatic insects. They often die after the spawning season from exhaustion. Their life expectancy is 3 to 4 years.