burbot vs ling

burbot

noun
  • A freshwater fish, taxonomic name Lota lota, which is similar to the ling and the cusk and spawns in the winter. 

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 burbot and ling occurred in a corpus of books? (source: Google Ngram Viewer )