After months of anticipation and excitement, the winners of the Wildlife Photographer of the Year 2011 were announced on 19 October at a gala awards ceremony held at the Natural History Museum, London.

And the Winner of the Underwater World category is ...

Paul Souders "The grace of giants"

American wildlife photographer Paul has won the Underwater World category of the 2011 VeoliaEnvironnement Wildlife Photographer of the Year award for his image "The Grace of Giants", a striking shot of two huge masses of flesh and tusk swimming with grace and power in the blue waters of Artic Norway.

Paul Souders went on a three week-long sea expedition off one of the world's most remote and northern islands - Spitzbergen, in the Svalbard archipelago, Norway - to photograph walruses.

Last night, representing Project AWARE as a proud sponsor of the Underwater World category of this prestigious wildlife photography competition, we were honoured to meet him.

Paul explained how magnificent yet frightening his encounter with walruses was. He knew they could be dangerous but he planned to appear as unthreatening as possible and hoped that the walruses would just be curious about him.

"Their curiosity sastified" says Paul, "they moved off in search of something more entertaining than a hyperventilating photographer".

As with all large arctic creatures, Walruses were hunted to near extinction in the 18th and 19th centuries, thanks to high demand for their blubber, oil, and tusks.Though their numbers are slowly increasing, the biggest danger they face now is climate change.

Thomas P Peschak, "Night Sharks"

At the gala ceremony, we were also thrilled and honored to meet former marine biologist and renowned underwater photographer Thomas P Peschak. Thomas spends most of the year pursuing marine conservation photography and ocean reportage. Thomas is a multiple winner in the Wildlife Photographer of the Year Awards and this year he received a World Press Photo Award for his work. He was also recently named as one of the 40 most influential nature photographers in the world.

The Underwater World Category Winners, Runner-up and Highly Commended images are:

• "The grace of giants" winner Paul Souders - USA
• "Salmon swipe" runner-up Paul Souders - USA
• "False killers, disguised dolphin" specially commended Clark Miller - USA
• "Beavering", highly commended Louis-Marie Preau - France
• "Night sharks", highly commended Thomas P Peschak - Germany / South Africa
• "Racing blue", highly commended Nuno Sa - Portugal
• "Lion among the shoal", highly commended Alex Tattersall - UK
• "The salmon jam", highly commended Thomas P Peschak - Germany / South Africa

The subject in the Underwater World category can be marine or freshwater species but they must be featured under the water. The pictures themselves should be unforgettable, either because of the behaviour displayed or because of their aesthetic appeal. Paul's winning image certainly meet all these criteria.

The VeoliaEnvironnement Wildlife Photographer of the Year Award went to Daniel Beltrá from Spain for Still Life in Oil. His picture has been chosen as the most striking and memorable of all the entries in the competition.

The winning images in all 14 categories will now be featured in an international exhibition beginning at the Natural History Museum, London, on Friday 21 October.

For more information about underwater photography see a list of top Ten Tips of Underwater Photographers from Project AWARE.

Congratulations to all winners and participants!