Salvelinus namaycush vs lake trout

Salvelinus namaycush

lake trout

noun
  • A large species of trout found in lakes in North America, Salvelinus namaycush. 

  • Whiting fried in batter and served in a sandwich. 

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