Wildlife Photographer of the Year: life and death in an underwater world

In the inky darkness of the ocean, Laurent documents a trio of camouflage groupers abandoning their swirling cloud of fertilised eggs to the current off the Fakarava Atoll, French Polynesia.

This unique spawning event only happens once a year. Laurent and his team returned each July for five years, diving day and night, to get this perfect shot.

The competition's esteemed judges selected this image out of 50,000 entries from professionals and amateurs for its unique composition and the important behaviour it exhibits.

Rosamund 'Roz' Kidman Cox OBE, Chair of the Jury, says, 'The image works on so many levels: it is surprising, intriguing and energetic, and has an otherworldly beauty. It also captures a magical moment - a truly explosive creation of life.'

An annual performance

The mating habits of the camouflage grouper are well known among divers and underwater photographers, many of whom, like Laurent, travel across the world to witness this magnificent spectacle of the natural world.

Guided by lunar cycles, around 18,000 of these reef-dwelling fish gather each year on the full Moon in July to spawn in a narrow channel linking the lagoon of the Fakarava Atoll with the open ocean.

The changing tide of the full Moon creates optimal mating conditions for these fish, as the strong current can pull the fertilised eggs out of the lagoon to the relative safety of the open ocean.

As the night of the full Moon grows closer, energy builds in the reef as the female fish prepare to spawn. Their frantic energy reaches a peak when the fish erupt upwards towards the ocean's surface, expelling their eggs in a clouded streak behind them.

The males follow suit, chasing the cloud of eggs and rushing to fertilise each one.

Dr Natalie Cooper, competition judge and evolutionary biologist and researcher at the Museum, says, 'This photo captures the chaos as females release their eggs and males rush to fertilise them. We loved the sense of movement and peril in the image.

'This is such a beautiful and atmospheric photo, and it also highlights an event that is becoming rarer in our oceans. These groupers are endangered, as are many other grouper species, mainly as a result of overfishing.

'Mass spawning events like this one are key to the species life cycle and survival but make them easy targets for fishing. It's crucial we protect these species and find sustainable solutions for people who depend on these fisheries for their livelihoods.'

Seven hundred sharks

Aside from human predators, a gathering this size of fish is sure to attract sharks. Every year, as the activity of camouflage groupers builds, so too does the presence of grey reef sharks looking to feed. 

Laurent's images demonstrate the frenzy of 18,000 groupers and close to 700 sharks gathering in a narrow stretch of water to breed and feed.

Although sharks are generally thought of as solitary animals, there is growing evidence that some species of shark work together to hunt in groups.

Laurent explains this behaviour, which he witnessed first-hand, on his Instagram post: 'In the south channel of Fakarava, the pack of grey reef sharks is very unique: unlike other atolls, the pack does not separate to hunt when the night comes but stays together as a group.

'This particular behaviour became the key question of our research about social interactions between the sharks. I came back to Fakarava with my team over five consecutive years to film, photograph, mark and study them.

'After analysing over 85,000 photographs and 350 hours of footage, we noticed that the sharks do have a sense of cooperation while they hunt. In fact, it became obvious that they follow an instinctive pattern in circling their prey.

'Unlike mammals, there is no sharing and when the prey is caught competition takes over. Nevertheless, the pack shows 25% success in catching a prey, when a pack of wolves only reaches 14%.'

The work behind a winning shot

As well as being visually striking, Laurent's Grand Title-winning image documents dynamic and unique animal behaviours that are out of reach to many biologists.

His winning photograph was taken on a 24-hour dive at a depth of 20 metres. Usually this would require a 20-hour ascent, but Laurent and his team managed to avoid this extra time by changing their gas mixtures to suit their depth.

As Laurent explains on his Instagram post, 'Starting with a HeO2 mix and switching to a N2O2 mix at the right timing, I could start my decompression while remaining at 20 metres and keep on doing my work of observation and photography.

'The actual ascent only lasted two hours and 20 minutes instead of 20 hours! It was the first time such a dive was done in open water. It is not a feat but rather the demonstration that with the appropriate method, this dive is possible for any well-prepared diver.'

Laurent's photos are the result of five years of expeditions, 3,000 hours of culminative night dives and 85,000 photographic triggers. 

This dedicated hard work has paid off with the Grand Title award in this year's Wildlife Photographer of the Year. David Lindo, competition judge and Urban Birder, David Lindo, says, 'Every time I look at the picture, I see something different. At first it was the overall shape and pattern of the white cloud with the fish exploding out. Then I saw what was really happening. Genius shot!'

Besides its visual merits and stylised look, Laurent's winning image reminds viewers of how alien the underwater world can be.

Dr Piotr Naskrecki, competition judge and entomologist, says, 'A swirling cloud of fertilised grouper eggs creates an otherworldly and powerful image that underscores how little we know about life below the waves.

'This unique photo allows us to witness a beautiful and dynamic phenomenon that, sadly, is becoming rarer as the unchecked plunder of the oceans continues.'