For most of our time in the water the blue sharks moved around us near the surface, sometimes close enough to make eye contact before gliding effortlessly away again. The experience changed completely when I held my breath and dived down deep.

Away from the surface the sharks became lost in a blue-green world with no reference and seemed less interested in me, perhaps even keeping their distance. As I started for the surface and looked up into the light, the blue of the shark was replaced by a magnificent sunburst and that unmistakable silhouette.

I was struck by just how graceful it was, completely at home in a place where I was the privileged visitor. Another amazing moment from an amazing day.