European pollock vs saithe

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. 

saithe

noun
  • The pollock or coalfish or coley (Pollachius virens). 

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