crawbob vs crustacean

crawbob

noun
  • An Australian species of freshwater crayfish, Cherax destructor; a yabby. 

crustacean

noun
  • Any arthropod of the subphylum Crustacea, including lobsters, crabs, shrimp, barnacles and woodlice. 

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