cusk vs ling

cusk

noun
  • A marine cod-like fish in the ling family Lotidae, Brosme brosme. 

ling

noun
  • Any of various marine food fish, of the genus Molva, resembling the cod. 

  • Common heather (Calluna vulgaris) 

  • Any of various varieties of heather or broom. 

  • A common ling (Molva molva). 

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