Whale sharks arrive early at Ningaloo Reef, Australia

I have never been to Ningaloo (great name, right?) - its WAY on the other side of Australia from where I grew up - but its a fascinating place.  Whale sharks gather there every year, and this year it looks like they turned up earlier than usual.  Whale shark aggregations are amazing events and the one at Ningaloo is one of the biggest.  Why gather? Why Ningaloo?  Why then?  How do they know where to go?  These are just some of the great mysteries of whale shark gatherings; its amazing that we know so little about the worlds largest fish.