fish trap vs lobster pot

fish trap

noun
  • A contraption made of wires, rods, fishing-net or other suitable materials with the purpose of catching fish alive. 

lobster pot

noun
  • A trap used to catch lobsters, resembling a crate with a small opening that a lobster can enter but has trouble exiting. 

  • Synonym of lobster-tailed pot (“kind of helmet”) 

  • Used other than figuratively or idiomatically: see lobster, pot: a pot for cooking a lobster in. 

How often have the words fish trap and lobster pot occurred in a corpus of books? (source: Google Ngram Viewer )