“What do you call a group of whales playing instruments?”/“An orca-stra.”

An orchestra riddle is:
 
Q: What do you call a group of killer whales playing musical instruments?
A: An orca-stra.
 
The joke was published in Boys’ Life magazine in May 1996.
 
   
Wikipedia: Killer whale
The killer whale or orca (Orcinus orca) is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. Killer whales are found in all oceans, from Arctic and Antarctic regions to tropical seas.
 
Google Books
May 1996, Boys’ Life, “Think & Grin,” pg. 74, col. 2:
Don: What do you call a group of killer whales playing music?
Ron: I don’t know. What?
Don: An Orca-stra. — Stephen Fuqua, Columbia, Md.
     
7 August 1998, Los Angles (CA) Times, “Laugh Lines; Pint-Sized Punch Lines,” pg. E2, col. 3:.
What does a killer whale conduct? An orca-stra. (Amelia Cox, 8, Rancho Palos Verdes, Point Vicente Elementary)
 
Google Groups: alt.teens.penpals
A Question I have about sex.
merry mcgrath
8/12/98
Laugh Lines from a Spanish fly:  1.  Why did the pig want to become an actor?  Because it was a big ham.  (Jack Nicholson??)  2.  What does a killer whale conduct?  An orca-stra. 
     
14 January 2000, Los Angeles (CA) Times, “The Kids’ Reading Room; Reading by 9; Jokes & Riddles,” pg. E8, col. 4:
What kind of band do whales play in? An orca-stra. (Ryan, 7, Inglewood)
 
Google Groups: alt.teens.penpals
In Tune.
merry mcgrath
1/18/00
What kind of band do whales play in?  An orca-stra.
 
Google Groups: alt.humor.puns
Kids puns of the Weak 02-01-05
Stan Kegel
2/1/05
(...)
What do you call a whale band?
An orca-stra! (Luke, 10)
 
Twitter
Brian Crouch
‏@BrianCrouch
If you had a symphony comprised of killer whales, would you call it an Orca-stra?
10:55 AM - 10 Nov 2008
 
Google Books
Reading is Funny!:
Motivating Kids to Read with Riddles
By Dee Anderson
Chicago, IL: American Library Association
2009
Pg. 117:
What would you call killer whales that play musical instruments?
an “orca-stra”
 
Twitter
pricechris
‏@pricechris
What do you call a whale band? // An Orca-stra! #ShamuTweets
10:17 PM - 19 Oct 2009
 
Twitter
Jose Torres
‏@Jose_embraceit
“What do you call a group of musical whales? An ORCA-stra.”  BAHAHAHA SO Lame but funny =p
7:01 PM - 17 May 2010
 
Twitter
Whales
‏@WhalesUK
What do you call a band of whales?
An ORCAstra!
2:01 PM - 20 Mar 2011
 
Twitter
Kitty Softpaws
‏@shero4hire
What do you call a group of killer musical whales? An ‘orcastra’!
4:12 PM - 2 Jan 2012
 
Google Books
Dad Jokes 2
By Peter Crumpton
PeteyRF Creative
2015
Pg. ?:
What do you call a group of killer whales playing instruments?
An Orca-stra.