twaite shad vs wolffish

twaite shad

noun
  • A fish in the herring family Clupeidae, Alosa fallax, found in the eastern Atlantic Ocean and the Mediterranean Sea. 

wolffish

noun
  • Any fish of the family Anarhichadidae. 

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