coalfish vs pollock

coalfish

noun
  • any of several blackish fish, especially Pollachius virens, a pollack, and Anoplopoma fimbria, sablefish. 

pollock

noun
  • Either of two lean, white marine food fishes, of the genus Pollachius, in the cod family. 

verb
  • To fish for pollock. 

  • To splatter, as with paint. 

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