Underwater Photographer of the Year 2023 winners revealedPublished16 February 2023Image source, © Kat-Zhou/UPY2023Image caption, The winners of the Underwater Photographer of the Year 2023 has been revealed as Kat Zhou for her photo of a river dolphin at sunset in Brazil. Kat says the water was so dark they were shooting blind! Kat was inspired by a myth that the river dolphins transform into men to try and make people fall in love with them.Image source, ©Oliver Clark /UPY2023Image caption, This photo by Oliver Clark shows a whale shark surrounded by hundreds of small fish in something called a bait ball. That's where the fish use the shark as protection - but this shot captures just when the shark is about to take a big bite of the fish! The image was runner up in the Up and Coming category.Image source, © Shane Gross/UPY 2023Image caption, These little guys are deep water fish called plainfin midshipman. They're baby fish, so only very small, which means the photographer Shane Gross needed a special zoom lens called a macro. One of them appears to be smiling for the camera! The picture was winner in the Macro category.Image source, © Alvaro Herrero/UPY 2023Image caption, This shot of a humpback whale tangled in ropes was the winner of the Marine Conservation category. Photographer Alvaro Herrero says taking it was the saddest moment he experienced in the ocean but says it is important to show us what is happening so we can make real change.Image source, © Victor Huertas/UPY 2023Image caption, This photo of a blacktip reef shark shows thousands of dots all over its skin. They are special organs which the shark uses to detect electric pulses caused by its prey. Photographer Victor Huertas wanted to show not all sharks are scary, in fact this baby shark has no teeth! The photo was runner up in the Black & White category.