black whale vs common blackfish

black whale

noun

  • North Pacific right whale (Eubalaena japonica) 

  • a sperm whale (Physeter catodon, syn. Physeter macrocephalus (family Physeteridae)) 

  • North Atlantic right whale (Eubalaena glacialis) 

common blackfish

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