“What do sea monsters eat?”/“Fish and ships.”

A “monster” riddle about fish and chips is:
 
Q: What do sea monsters eat?
A: Fish and ships.

 
The joke has been cited in print since at least 1966.
 
“What does a physicist have for lunch?”/“Fission chips” is another “fish and chips” riddle.
   
 
5 July 1966, Toronto (ON) Daily Star, pg. 21, col. 5 ad:
Joe: What do whales and sea-monsters eat?
Moe: I don’t know.
Joe: Fish and ships.
(Thorncrest used cars.—ed.)
 
16 September 1973, The Sun-Herald (Sydney, Australia), “Ha Ha Ha,” Comic Sec., pg. 6, col. 2:
Q. What do sea monsters eat?
A. Fish and ships!
Frances Schembri (12), cartwright
 
13 November 1976, The Guardian (UK), Richard Boston column, pg. 9, col. 2:
What do sea monsters eat? Fish and ships.
 
16 August 1979, Newsday (Long Island, NY), “Smiles,” Kidsday, pg. B18, col. 3:
What do monsters eat?
Fish and ships.
Nina Potash, Malverne
 
22 February 1983, Morning Advocate (Baton Rouge, LA), “A Little Bit of humor,” The Bubble Gum Rapper, pg. 1, col. 3:
Lynn: What do sea monsters eat?
Chris: Fish and ships.
 
Google Books
Jokes:
Outrageous bits, atrocious puns, and ridiculous routines for those who love jests

By Paul Dickson
New York, NY: Delacorte Press
1984
Pg. 63:
What do sea monsters eat?
Fish and ships.
 
17 October 1987, The Times (Trenton, NJ), “Good Humor,” pg. B1, col. 1:
Katie Gonyer of Stark, N.H. asks: “What do English sea monsters have for dinner?”
“FIsh and ships.”
 
Google Books
Smart Alec’s Revolting Jokes for Kids
By Ward Lock & Co Ltd
New York, NY: Ballantine Books
1989, ©1987
Pg. 210:
What’s a sea monster’s favorite supper?
Fish and ships.
 
Google Books
Monster Mayhem:
Jokes to Scare You Silly

By Sam Schultz
Pictures by Brian Gable
Minneapolis, MN: Carolrhoda Books, Inc.
2003
Pg. 27:
Q: What do sea monsters eat for dinner?
A: Fish and ships.
 
Twitter
Dani
‏@Doduti
what did the sea monster eat? fish and ships
9:50 PM - 21 Nov 2008
 
Google Books
Scooby-Doo Monster Jokes
By Michael Dahl
Illustrated by Scott Jeralds
North Mankato, MN: Stone Arch Books
2015
Pg. ?:
What do sea monsters like to eat?
Fish and ships!