jack mackerel vs northern pike

jack mackerel

noun
  • Any of various edible fish, especially of genus Trachurus, but also genera Caranx, Acanthocybium and Euthynnus. 

northern pike

noun
  • A species of pike, Esox lucius. 

How often have the words jack mackerel and northern pike occurred in a corpus of books? (source: Google Ngram Viewer )