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A photograph showing the exact moment a pack of grey reef sharks catch and devour a parrotfish sees Briton Richard Barnden named Underwater Photographer of the Year 2019.
The picture, The Gauntlet, was taken late at night on the reefs of French Polynesia in the centre of the Pacific Ocean.
Image copyrightRichard Barnden/UPY2019
"As I descended, hundreds of sharks covered the bottom. This unlucky parrotfish flinched - and that tiny movement alerted the swarm of sharks," said Barnden.
"The mayhem hurtled straight towards me and I instinctively pressed the shutter, moments later all that remained was a rain of parrotfish scales in the darkness - and this photo on my camera."
Alexander Mustard, who chaired the panel of judges, said; "Photography is about preserving moments - and what an unforgettable instant this is.
"Using a wide-angle lens, the photographer takes us into the full drama of the hunt, as a melee of grey reef sharks rise like a breaking wave to tear apart their prey, truly revealing the ocean's wilder side."
Eduardo Acevedo, from Tenerife, was named Marine Conservation Photographer of the Year 2019 for his photo showing a loggerhead turtle entangled in a discarded plastic fishing net.
Image copyrightEduardo Acevedo/UPY2019
Korean Taeyup Kim was named Up & Coming Underwater Photographer of the Year 2019 for a technically challenging image half in and half out of the water, which shows healthy corals growing in front of a resort in French Polynesia.
"This photo was physically tough to shoot, holding the heavy camera exactly in this position while floating in the water," said Kim.
Image copyrightTaeyup Kim/UPY2019
The title of Most Promising British Underwater Photographer 2019 goes to Malcolm Nimmo, from Plymouth.
His image, of a compass jellyfish, was taken while snorkelling off the Scilly Islands.
"Maintaining both the surface features and subject illumination requires high strobe power settings and hence careful strobe positioning," said Nimmo.
"Hopefully this image highlights the beautiful marine environments we are lucky to have around the UK."
Image copyrightMalcolm Nimmo/UPY2019
The competition had 13 categories, testing photographers with themes such as Macro, Wide Angle, Behaviour and Wreck Photography, as well as four categories for photos taken in British waters.
Image copyrightFrançois Baelen/UPY2019 Image caption
François Baelen's wide-angle shot of a resting humpback whale was taken 15m (50ft) below the surface. While free diving, Baelen was also able to capture his fellow diver and the whale's curios calf.
Image copyrightFabio Iardino/UPY2019 Image caption
Fabio Iardino won the Macro category with this image of a swiftly moving sepiola in the Gulf of Trieste, in north-east Italy.
Image copyrightRené B. Andersen/UPY2019 Image caption
The wreck of The HMS Audacious sits off the northern coast of County Donegal. René B Andersen battled against currents to capture this long-exposure shot.
Image copyrightScott Portelli/UPY2019Image caption
Scott Portelli captured this group of whales and dolphins moving at high speed off the coast of Vava'u, Tonga. "After 16 years documenting some of the most common and unusual behaviour seen by humpbacks in the region, this was a truly heart-thumping and adrenaline-pumping action to be a part of," said Portelli.
Image copyrightNicholas Samaras/UPY2019Image caption
This illuminating portrait of a small ray was taken by Nicholas Samaras in the waters of Stratoni, on the north-eastern coast of the Chalkidiki peninsula, in northern Greece.
Image copyrightHenley Spiers/UPY2019 Image caption
This striking black-and-white shot by Henley Spiers captures a single cormorant diving into a school of fish.
Image copyrightEnrico Somogyi/UPY2019Image caption
Enrico Somogyi's image of fishermen at work as a hairy frogfish lurks below was achieved by using a double exposure setting in the camera.
Image copyrightMatej Begoc/UPY2019Image caption
This shot was taken by Matej Begoc in a remote bay of Solta island, during a sailing trip in Croatia.
Image copyrightRobert Bailey/UPY2019Image caption
A scuba diver approaches a cluster of colourful jewel anemones off the coast of Scilly in this shot by Robert Bailey.
Image copyrightArthur Kingdon/UPY2019 Image caption
Arthur Kingdon's picture was made during a dive in Loch Duic, on the west coast of Scotland. A long clawed squat lobster poses outside his home, made from a piece of plastic pipe, while sea loch anemones decorate the entrance.
Image copyrightVictoria Walker/UPY2019Image caption
A shoal of mackerel are caught out by the spring low tide in St Ives harbour, Cornwall, in Victoria Walker's wide-angle shot.
Image copyrightMartin Edser/UPY2019Image caption
An inquisitive young seal gave photographer Martin Edser a warm welcome during a dive off the coast of the Farne Islands, Northumberland.
Image copyrightNoam Kortler/UPY2019Image caption
A seahorse trapped in a plastic cup drifts in the current in the Red Sea resort of Eilat, Israel. This shot was taken by Noam Kortler, before releasing the creature, to highlight the damage done by plastic products.