orca vs sturgeon

orca

noun
  • A sea mammal (Orcinus orca) related to dolphins and porpoises, commonly called the killer whale. 

sturgeon

noun
  • Any marine or freshwater fish of the family Acipenseridae that are prized for their roe and are endemic to temperate seas and rivers of the northern hemisphere, especially central Eurasia. 

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