Atlantic pollock vs European pollock

Atlantic pollock

noun
  • European pollock, Pollachius pollachius. 

European pollock

noun
  • Fish of the species Pollachius pollachius, which live in the Northern Hemisphere, particularly off the coast of Norway and the United Kingdom. 

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