John Paul Jones (born John Baldwin on January 3, 1946) is an English multi-instrumentalist musician, and was known for being the bass guitarist, the keyboardist and the mandolinist for rock band Led Zeppelin.

from http://www.geocities.com/shankar00/jpjsite.html (in 'Trivia'):

• Does JPJ eat meat?
  

  "I stopped eating meat for a number of reasons - I don't like what they put into it, and raising cattle is not a very productive use of land. Since I've stopped [eating meat], I've felt better." He does eat fish though - "I love fresh tuna, salmon, shellfish, and crab... I'm very keen on Japanese food, especially sushi."

• Then what does JPJ eat while on tour?
  

  "Even when touring, I've always found good places to eat. You can't live on drugs and alcohol alone."
  

See also Jimmy Page - there are many online references to him being vegetarian, but none with any specific evidence.