black goby vs shad

black goby

noun
  • Any of the species Gobius niger of ray-finned fishes, found in the eastern Atlantic Ocean and the Mediterranean and Black Seas. 

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). 

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