David Doubilet: There was a long reef, kind of a peninsula of a reef that stuck out 50, 60 feet down, near New Ireland in Papua New Guinea — very clear water.  I swam over it. I was alone, and I swam over it, and I was instantly surrounded by this enormous school of chevron barracuda.  And what these barracudas do is they do this wonderful thing, which is a defensive mechanism. They make a perfect circle, absolutely geometric perfect circle.

And geometry in the ocean is something that doesn’t exist in a weightless, cornerless world.  There I was in the middle of this perfect circle, and I realized that I was in the middle of a picture that I wanted to take. It’s one of these things — it’s a terrible realization. So I swam back to the boat, and I talked to the captain. Her name was Dinah Halstead.  I said, “Dinah, you got to come with me.” She and her husband, Bob, ran a boat called Toledo, and she jumped into the water in about two minutes, and we swam back to there. We swam side by side back to the barracudas, side by side.  And as we got into this school — and they were still there, which is a wonderful thing — they began to circle again.

I crossed my fingers. I dove to the bottom. At about 45 feet, I rolled on my back, and I looked up. And Dinah was in the middle of the circle, and the afternoon sun was glinting against the sides of the barracudas, like a perfect silver wall.  And then she did something amazing.  Instinctively, she held out her hand, like a ballet dancer, like a pas de deux — or one half of a pas de deux — and the barracudas circled.  They went three times around her, and then they disappeared.  They broke up. They went into a single line and they swam off — off the edge of this blue peninsula of coral.