Dozens of whale sharks have been seen at Ningaloo Reef.
They normally frequent the reef between April and July but last Monday a pilot scouting for manta rays spotted 25 whale sharks at Coral Bay.
Sixteen were seen on Tuesday, 16 on Thursday and five on Friday.
Whale shark expert and ECOCEAN director Brad Norman said it was unusual for whale sharks to be at Ningaloo at this time of year, but there was plenty of food.
"We're not sure whether that's going to continue," he said.