Here's a quick description I found on the web...
A true barrier reef, Ningaloo Reef Marine Park has recently become famous in the diving community for its concentration of whale sharks during March and April. Relatively scarce in other dive areas, the huge plankton feeders congregate in the area drawing divers from all over the world. Boats hire spotter planes to locate the sharks, which radio their whereabouts to groups of waiting divers. While there is other diving on the reefs, nothing can top the appeal of the whale sharks. Shops in Exmouth and Perth run special whale shark trips. Best diving: Whale sharks appear March to May
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