Solvin Zankl / Baby Olive Ridley sea turtle (Lepidochelys olivacea) struggles against the swell to swim away from the beach where it hatched, Ostional, Costa Rica. October. Winner of the Underwater category of the G...

SCOTLAND: The Big Picture / Grey seal (Halichoerus grypus) using freshwater pools along the shore line and in the adjacent fields as place to learn to swim, Orkney, Scotland, UK, April.

Yukihiro Fukuda / Japanese giant salamander (Andrias japonicus) watching a fish swim by, Hino River, Tottori-ken, Japan, September.

Marie Read / Eared grebes (Podiceps nigricollis), pair, one adult feeding one of two chicks riding on the other adult's back, Bowdoin National Wildlife Refuge, Montana, USA

Marie Read / Eared grebes (Podiceps nigricollis), pair, one adult carrying food (damselfly) for two chicks riding on the other adult's back, Bowdoin National Wildlife Refuge, Montana, USA

Marie Read / Eared grebes (Podiceps nigricollis), pair, one adult feeding chick riding on the other adult's back, Bowdoin National Wildlife Refuge, Montana, USA

Brent Stephenson / Polar bear (Ursus maritimus) mother and large second year cub swim across calm water, Scott Inlet, Baffin Island, Canadian Arctic, August. Vulnerable species.

Luciano Candisani / Jacare Caiman (Caiman yacare) waiting for fish to swim through open mouth in wetland, Pantanal, Brazil

Luciano Candisani / Jacare Caiman (Caiman yacare) waiting for fish to swim through open mouth in wetland, Pantanal, Brazil

Matthew Maran / Great created grebe (Podiceps cristatus) with chick following, and person swimming in pond, Hampstead Heath, London, July 2014.

Alex Mustard / A long exposure renders Bar jacks (Carangoides ruber) as ghostly trails as they swim around a sponge, on a coral reef, at night. East End, Grand Cayman, Cayman Islands. Overall winner of GDT competiti...

Alex Mustard / A shoal of Golden grey mullet (Liza aurata) swim in the surf breaking on the shore of El Hierro Island. Canary Islands, Spain. East Atlantic Ocean.