“Where do shellfish go to borrow money?”/“The prawn broker.”

“Prawn” sounds to some like “pawn.” A riddle has been cited in print since at least 2001:
 
Q: Where do shellfish go to borrow money?
A: The prawn broker.
       
“How could the dolphin afford to buy a house?”/“He prawned everything” is another “prawn”/“pawn” joke.
         
         
Google Books
Extremely Good Clean Jokes for Kids
By Bob Phillips
Eugene, OR: Harvest House Publishers
2001
Pg. 111:
Karlotta: Where do shellfish go to borrow money?
Katrina: Beats me.
Karlotta: To the prawn-broker.
 
Google Groups: uk.people.silversurfers
Fish jokes
Anita Carter
3/21/02
Where do shellfish go to borrow money ?
To the prawn broker !
   
Google Groups: alt.tv.star-trek.enterprise
[OT] [AOB] [OO] [MAU] [MAU] JFF
Derek
10/4/03
(...)
>> Where do shellfish go to borrow money? 😉
>
> You’re mean
Just because you don’t know the punchline does NOT make me mean.
 
(To the PRAWN broker!)
   
Google Books
Penguin Pocket Jokes
By David Pickering
London, UK: Penguin Books
2006
Pg. ?:
Where do shellfish go to borrow money?
To the prawn broker.
 
Twitter
Jon Lansner
@jonlan
Bad joke ... Q: Where do shellfish go to borrow money? A: To the prawn broker.
10:28 PM - 20 May 2008
     
16 July 2009, The Sun (London, UK), “Have a laugh!,” pg. 16:
WHERE do shellfish go to borrow money? The prawn broker.
   
Google Books
1001 Amazing Jokes
By Jack Goldstein
Andrews UK Limited
2013
Pg. ?:
Where do shellfish go to borrow money?
To the prawn broker!
 
Reddit—Cleanjokes
Where do shellfish go to borrow money? (self.cleanjokes)
submitted July 6, 2018 by madazzahatterQuality “Ugh” Contributor
The prawn broker.