someone posted a video of this. you can see people as reference to the size of the whale sharks. I do not think they are any mature whale sharks in the aquarium.
The one in the link has the largest acrylic viewing window in the world. and was for a short time the largest in the world. they are so close to the ocean that they Pump water from the ocean into this tank. and then re-circulate it back to the ocean (think Drip system on riods)