British Waters Wide Angle category runner-up. Grass snake swimming along a garden pond by Jack Perks (UK)in Nottinghamshire, UK. “I’m always on the lookout for unusual freshwater subjects and grass snakes are a species I’ve been after for years. I was told about a pond where the odd grass snake hangs around the lilly pads for frogs. I put my drysuit on and got into the water and could see one slithering along the surface. Slowly making my way towards it with my head only just poking above I got the spilt shot”. (Photo by Jack Perks/Underwater Photographer of the Year 2019)

Novice DSLR (Digital single-lens reflex camera), 2nd Place. “Smile of a Friend”, American Crocodile (Crocodylus acutus) in Jucaro, Cuba. (Photo by Antonio Pastrana/The Ocean Art 2018 Underwater Photography Competition)

Split-view of a killer whale at sunrise off the coast of Northern Norway. At least half of the world’s killer whale populations are doomed to extinction due to pollution of the oceans, a new study says. (Photo by Audun Rikardsen/Science)

Neon sea creatures have been captured lighting up the ocean with their vibrant colors – in what looked like a scene from Avatar. Photographer Simon Pierce, 39, took the images over several months after visiting both Nosy Sakatia in Madagascar and Mafia Island in Tanzania recently. (Photo by Simon Pierce/Caters News Agency)

Teeming with images of spectacular underwater scenes from around the world, Call of the Blue is the culmination of a five-year project by the photographer and ocean conservationist Philip Hamilton. This groundbreaking book includes contributions from acclaimed scientists and ocean “guardians”, who reveal what drove them to answer the call of the blue. (Photo by Philip Hamilton/The Guardian)

A series of beautiful shots of divers swimming near sunken ships have emerged. Alex Voyer, 39, was sailing around the Caribbean on a 60-foot boat when he stopped for a dive. The images show amazing shipwrecks as free divers explore the seabed. Here: A diver swims in the shallow water under a pier. (Photo by Alex Voyer/Caters News Agency)

Ryo Minemizu, one of Japan’s emerging stars in the field of marine life photography and the 2017 winner of the Nikkei National Geographic photography prize, captures the beauty and complexity of plankton that drift in our planet’s oceans and other bodies of water in meticulous detail. Here: Batesian mimicry by a Soleichthys fish larva. (Photo by Ryo Minemizu/The Guardian)

Impressive images of these alien-like creatures were captured underwater – photographer Cai Songda is a keen diver and did not miss the chance to snap pictures of the unique “aliens”. Here: A Tremoctopus Gracilis in the waters around Anilao, Philippines. (Photo by Cai Songda/Caters News Agency)