“How do you catch a school of fish?”/“With a bookworm.”

A popular riddle about a “school of fish” is:
 
Q: How do you catch a school of fish?
A: With a bookworm.
 
The joke has been cited in print since at least 1990.
 
   
17 July 1990, State Times (Baton Rouge, LA), “A Little Bit of Humor,” The Bubble Gum Rapper, pg. 1, col. 3:
Steve: How do you catch a school of fish?
Ginger: With a bookworm!
 
Old Fulton NY Post Cards
23 June 1993, Clinton (NY) Courier, “Kid’s Riddles,” pg. 7, col. 3:
What kind of bait do you use to catch a school of fish?
Bookworms!
 
Google Groups: schl.sig.lmnet
HIT: Library Jokes and Riddles
.(JavaScript must be enabled to view this email address)
10/15/96
(...)
What’s the best way to catch a school of fish?
With bookworms
 
Google Groups: schl.sig.lmnet
GEN: School jokes
Paul & Deborah Connell
2/26/98
(...)
What bait do you use to catch a school of fish?
Bookworms.
 
18 November 1998, Titusville (PA) Herald, “Cryptoquip,” pg. 6, col. 4:
THE MORON THINKS HE’LL BE ABLE TO CATCH A SCHOOL OF FISH WITH A BOOKWORM.
 
Google Books
Mind Knots:
A Book of Riddles
By Mark Ziegler
Illustrated by Ryan Haugen
Minneapolis, MN: Picture Window Books
2006
Pg. 11:
How do you catch a school of fish?
With a bookworm.
 
Twitter
Kids Jokes
‏@KidzJokes
How do you catch a School of Fish??? With a Bookworm!!! hehehe!!! #Jokes
12:17 PM - 13 Dec 2009
 
Google Books
Wise Crackers:
Riddles and Jokes about Numbers, Names, Letters, and Silly Words
By Michael Dahl
Mankato, MN: Picture Window Books
2011
Pp. 38-39:
HOW DO YOU CATCH A SCHOOL OF FISH?
WITH A BOOKWORM.