brown trout vs namaycush

brown trout

noun
  • A species of nonmigratory freshwater trout, Salmo trutta, with dark spotted skin, native to Europe and Asia. 

namaycush

noun
  • The togue: a large North American lake trout, Salvelinus namaycush, usually spotted with red. 

How often have the words brown trout and namaycush occurred in a corpus of books? (source: Google Ngram Viewer )