allis shad vs seawolf

allis shad

noun
  • A herring-like fish (Alosa alosa), of the eastern Atlantic that migrates to fresh water to spawn. 

seawolf

noun
  • A strong-jawed North Atlantic fish of wolffish family Anarhichadidae, Anarhichas lupus. 

  • Any of various dangerous people and animals that attack at sea. 

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