The Brown Trout is native to most of Europe, part of North Africa and western Asia. It has two main
population types: a fully freshwater morph (which some split into lakes vs rivers) and a marine morph which returns
to freshwater rivers to spawn (like the related Atlantic Salmon). It has been introduced outside its native range.
Brown Trout resident in rivers and lakes are olive-brown with dark brown spots. Ocean-going Brown Trout,
often called Sea Trout, become silver with dark spots. The two are genetically identical. Sea Trout are often larger, the range
for adult Brown Trout being 40-80cm with some exceptionally reaching a metre.