Brown trout

The brown trout is a species of salmonid ray-finned fish and the most widely distributed species of the genus Salmo, endemic to most of Europe, West Asia and parts of North Africa, and has been widely introduced globally as a game fish, even becoming one of the world's worst invasive species outside of its native range. Brown trout are highly adaptable and have evolved numerous ecotypes/subspecies. These include three main ecotypes: a riverine ecotype called river trout or Salmo trutta morpha fario; a lacustrine ecotype or S. trutta morpha lacustris, also called the lake trout (not to be confused with the lake trout in North America); and anadromous populations known as the sea trout or S. trutta morpha trutta, which upon adulthood migrate downstream to the oceans for much of its life and only returns to fresh water to spawn in the gravel beds of headstreams.[citation needed] Sea trout in Ireland and Great Britain have many regional names: sewin in Wales, finnock in Scotland, peal in the West Country, mort in North West England, and white trout in Ireland.

Source: Wikipedia