shad vs wolffish

shad

noun
  • Any one of several species of food fishes that make up the genus Alosa in the family Clupeidae, to which the herrings also belong; river herring. 

  • The bluefish (Pomatomus saltatrix). 

wolffish

noun
  • Any fish of the family Anarhichadidae. 

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