The world’s biggest fish is coming straight at me. His mouth is a yawning slit, his gills a languid flutter, his eyes glass beads studded on opposite sides of a capacious, flat-topped head. He appears to have spat out a row of bright yellow teeth, but as he closes in on me I see they’re actually golden trevallies gliding in a scrambled line before him, tiny sentries welcoming him home.

It’s still early in the whale shark season here at Ningaloo Reef, but already these gargantuan fish – despite their misleading name they’re sharks, not whales – are arriving for their annual sojourn.