namaycush vs steelhead

namaycush

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

steelhead

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

  • The ruddy duck. 

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