steelhead vs tuladi

steelhead

noun
  • The anadromous form of the rainbow trout, Oncorhynchus mykiss. 

  • The ruddy duck. 

tuladi

noun
  • A large lake trout, Salvelinus namaycush, found mainly in Canada and northern areas of the US. 

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