In the crystal-clear waters of the Red Sea a school of bigeye trevally formed a circular shoal a few metres from Alexander’s lens. For 20 years Alexander had been coming to photograph the summer spawning of reef fish. ‘A big lure that sees me return each year is that I always see something new,’ he says.

The spawning population of bigeye trevally is boosted by the protected status of Ras Mohammed National Park as a no-fishing marine reserve. Adult bigeye trevallies are vulnerable to attack from larger fish. During the spawning season they school both to protect themselves and to increase the likelihood of contact between eggs and sperm.