North Pacific hake vs jack salmon

North Pacific hake

jack salmon

noun
  • Sander vitreus. 

  • A Chinook salmon that returns to the fresh water one or two years early. 

  • Sander canadensis. 

  • Merluccius productus, a ray-finned fish found in the northeast Pacific Ocean. 

How often have the words North Pacific hake and jack salmon occurred in a corpus of books? (source: Google Ngram Viewer )