blackfish vs sperm whale

blackfish

noun
  • A pilot whale, genus Globicephalus (occasionally also used for various other whales). 

  • The Atlantic salmon, Salmo salar, especially a female after spawning. 

  • Any of various dark-coloured fish of the Old World, especially the rudderfish (Centrolophus niger). 

  • Any of various dark-coloured fishes of Australasia, especially the luderick, Girella tricuspidata, and a freshwater fish, Gadopsis marmoratus. 

  • Either of two dark-coloured fish of the west Atlantic, the tautog of New England (Tautoga onitis) and the black sea bass (Centropristis striata). 

verb
  • To go fishing for blackfish. 

  • To adopt signifiers of black identity (for example, by darkening the skin, or wearing traditionally black hairstyles). 

sperm whale

noun
  • A whale (Physeter catodon, syn. Physeter macrocephalus), the largest of the toothed whales. 

  • Any whale in the superfamily Physeteroidea, which also includes the small whales of genus Kogia. 

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