David Fleetham / Pair of White-eyed moray eels (Muraena thyrsoides) share the hole of a mooring block off Bali, Indonesia.

Angelo Gandolfi / Gannets (Morus bassanus) courtship behavior on nest on abandoned boat, La Spezia Gulf, Italy. Mediterranean Sea. July.

David Noton / Canoes on the moored on the Nam Song River at Vang Vieng, Laos, March 2009.

Tom Gilks / Fishermen preparing nets, Remba Island, Lake Victoria, Kenya.

Merryn Thomas,Merryn Thomas / Black and white image of three punts, Mevagissey, Cornwall, England, January.

Franco Banfi / View of Procida, the small harbour of Corricella, island near Ischia Island, Italy, Tyrrhenian Sea, Mediterranean

Barrie Britton / Snow covered fishing boats in Sitka Harbour, Alaska. Photograph taken on location for BBC TV series 'Nature's Great Events', March 2008.

Billy Black / Gull (Larinae) sitting on mooring ball in calm waters on misty day. Robinhood, Maine, USA, July 2010.

Wild Wonders of Europe / López / Lake Usma viewed from a mooring stage on Moricsala Island with dark clouds, Moricsala Strict Nature Reserve, Latvia, June 2009 UNAVAILABLE FOR COMMERCIAL USE WITHOUT PRIOR CONSENT

Ashley Cooper / A litter trap on the River Thames, London, UK. January 2000

Ashley Cooper / A sign about Manatees in Miami Beach, Florida, USA. October 2015

Ashley Cooper / Sunrise over the harbour of Ushuaia, Tierra del Fuego, Argentina. February 2014.

Andy Rouse / Polar bear (Ursus maritimus) playing with ship's mooring rope, Svalbard, Norway. 2016.

Andy Rouse / Polar bear (Ursus maritimus) playing with ship's mooring rope, Svalbard, Norway. 2016.

Constantinos Petrinos / Anemone hermit crab (Dardanus pedunculatus) on mooring line carrying sea anemones. Lembeh Strait, North Sulawesi, Indonesia.

Constantinos Petrinos / Anemone hermit crab (Dardanus pedunculatus) on mooring line carrying sea anemones. Lembeh Strait, North Sulawesi, Indonesia

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway.

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway. Sequence 5 of 5

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway. Sequence 4 of 5

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway. Sequence 3 of 5

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway. Sequence 2 of 5

Andy Rouse / Polar bear (Ursus arctos) playing with ship's mooring rope, Svalbard, Norway. Sequence 1 of 5

Peter Lewis / Boat moored at jetty in autumn on Derwent Water, Keswick, Lake District, Cumbria, England, UK. November 2013.

Merryn Thomas / Yachts moored in Ushuaia, capital of Tierra del Fuego, Antartida e Islas del Atlantico Sur Province, Argentina. January 2014.

Merryn Thomas / Thunderstorm over Copacabana, Lake Titicaca, Bolivia, December 2013.

Gary K. Smith / Rio de Santa Barnaba, Dorsoduro Venice, Italy, April.

Gary K. Smith / Venetian water taxis mooring point, Venice, Italy.

Gary K. Smith / Maintenance barge repairing mooring posts on Grand Canal, Venice, Italy.

Gary K. Smith / Maintenance barge repairing mooring posts on Grand Canal, Venice, Italy.

Gary K. Smith / Maintenance barge with crane and replacement mooring posts, Venice, Italy.

Nick Turner / Autumn mist on Kennet and Avon Canal at Dundas Aquaduct, Bath, UK. September 2015.

Nick Turner / Autumn mist on Kennet and Avon Canal, Dundas Aquaduct, Bath, UK. September 2015.

Nick Turner / Autumn mist on Kennet and Avon Canal at Dundas Aquaduct, Bath, UK. September 2015.

Nick Turner / Autumn mist on Kennet and Avon Canal, Bath, UK. September 2015.

Nick Turner / Barges in autumn mist on Kennet and Avon Canal, Bath, UK. September 2015.

Ernie Janes / Sailing boats and view towards Blakeney Village, Morston Quay, Norfolk, UK, August.

Ernie Janes / Wells Harbour with boats moored, Norfolk, England, UK, September 2015.

Nick Upton / Moored fishing boats in Apothika village harbour, with clouds over Mount Olympus in the background, Lesbos/Lesvos, Greece, May 2013.

Nick Upton / Moored fishing boats in Lipsi town harbour, with Agios Ioannis church in the background, Lipsi, Dodecanese Islands, Greece, August 2013.

Kirkendall-Spring / Doug Anderson fishing on Stanley Lake during a rain shower with rainbow, Stanley Lake National Recreation Area, Idaho, USA. July 2015. Model released.

Kirkendall-Spring / Doug Anderson fishing on Stanley Lake during rain shower, with rainbow, Stanley Lake National Recreation Area, Idaho, USA. July 2015. Model released.

Constantinos Petrinos / Trans Maldivian hydroplane (seaplane) docked next to a small floating platform, to transport tourists to various islands. Male, Maldives, Indian Ocean, April 2010.

Constantinos Petrinos / Trans Maldivian hydroplane (seaplane) is docked, hydroplane airport, Male, Maldives, Indian Ocean, April 2010.

Constantinos Petrinos / Small fisherman houses, fishing boats and an abandoned and sinking wooden fishing boat, close to the city of Bitung. Lembeh Strait, Molucca Sea, Sulawesi, Indonesia, Indo-Pacific, March.

Constantinos Petrinos / Three Indonesian fishing boats anchored side by side, close to the city of Bitung, Lembeh Strait, Molucca Sea Sulawesi, Indonesia, Indo-Pacific, March 2013

Constantinos Petrinos / Old fishing boat abandoned and sinking among a cluster of boats confiscated by the Indonesian Port Police (mainly for illegal fishing without a proper licence). Port Police station, Bitung. Lembeh Str...

Franco Banfi / RIBs docked at Vila do Porto harbour, Santa Maria Island, Azores, Portugal, Atlantic Ocean, August 2014.

Kirkendall-Spring / Fishing fleet docked at Fisherman's Terminal on Salmon Bay in Seattle's Ballard district, Washington, USA, May 2015.

Kirkendall-Spring / Fishing fleet docked at Fisherman's Terminal on Salmon Bay in Seattle's Ballard district, Washington, USA, May 2015.

Charlie Summers / Sedna IV yacht, a 51-meter, three masted, steel-hulled sailing schooner, anchored in Arthur Bay at Palmer Station, Antarctica. January.

Charlie Summers / ONORA 19 meter cutter ship, anchored outside, Palmer Station, Antarctica. January 2006.

Angelo Gandolfi / Gannets (Morus bassanus) nesting on abandoned boat, La Spezia Gulf, Italy. Mediterranean Sea. July.

Angelo Gandolfi / Gannets (Morus bassanus) courtship behavior on nest on abandoned boat, La Spezia Gulf, Italy. Mediterranean Sea. July.

Angelo Gandolfi / Gannets (Morus bassanus) nest on abandoned boat with chick, La Spezia gulf, Italy. Mediterranean sea. July.

Juergen Freund / Aerial view of Yachts docked in Savusavu. Cakaudrove, Northern Division, Vanua Levu, Fiji. December 2013.

Frederique Olivier / French Icebreaker L'Astrolabe on the edge of the fast ice off Dumont D'Urville station, with helicopter moving supplies onto the ship. Antarctica. December 2014.

Onne van der Wal / Boats moored in Hamilton Island Marina, Whitsunday Islands, Queensland, Australia, November 2012.

Onne van der Wal / Boats moored in Hamilton Island Marina, Whitsunday Islands, Queensland, Australia, November 2012.

Onne van der Wal / Luxury yachts moored off Whitsunday Island, Queensland, Australia. November 2012.

Onne van der Wal / Marina at Hamilton Island Yacht Club, Whitsunday Islands, Queensland, Australia. November 2012.

Onne van der Wal / Boat moored on Hamilton Island, Whitsunday Island group, Queensland, Australia. November 2012.

Onne van der Wal / Boats moored in Hamilton Island Marina, Whitsunday Islands, Queensland, Australia, November 2012.

Steve O. Taylor (GHF) / Boats on Kapuas River, Singkawang, West Kalimantan, Indonesia Borneo. June 2010.

Kirkendall-Spring / Long tail boats docked on the Khlong Bangkok Yai (canal), Bangkok Thailand, September 2014.

David Tipling / Brent geese (Branta bernicla) feeding in tidal creek at low tide, Brancaster, Norfolk, UK, April 2014.

Brent Stephenson / Arctic tern (Sterna paradisaea) sitting on a blue ships mooring line. Hofn, Iceland. July.

Brent Stephenson / Arctic tern (Sterna paradisaea) sitting on a blue ships mooring line. Hofn, Iceland. July.

Kim Taylor / Laughing gulls (Larus atricilla) resting on boat. Tobago, West Indies.

Enrique Lopez-Tapia / Traditional Melanesian outrigger boat, Ile des Pins (Pine Island), New Caledonia, September 2008.

Rob Cousins / Sailing boats moored in Lympstone harbour, Exe Estuary, Devon, UK, July 2013.

David Noton / Weaver making silk cloth, Luang Prabang, Laos, March 2009.

David Noton / Colourful canoes moored on the Nam Song River at Vang Vieng, Laos, March 2009.

Kirkendall-Spring / Fishing boats of the Gay Fish Company docked along Ward Creek, Frogmore, South Carolina, USA.

Kirkendall-Spring / Fishing boats of the Gay Fish Company docked along Ward Creek, Frogmore, South Carolina, USA.

Kirkendall-Spring / Shrimp boats docked on Shem Creek in the town of Mount Pleasant, South Carolina, USA.

Steve O. Taylor (GHF) / Canoes moored on side of Lake Victoria, Uganda, March 2012.

Steve O. Taylor (GHF) / Dugout wooden canoes on bank of river, Salonga National Park, Equateur, Democratic Republic of the Congo, May 2012.

Steve O. Taylor (GHF) / Men with dugout wooden canoes on riverbank, Monkoto, Salonga National Park, Equateur, Democratic Republic of the Congo, May 2012.

Steve O. Taylor (GHF) / Man and woman with vegetables in dugout wooden canoes on riverbank, Monkoto, Salonga National Park, Equateur, Democratic Republic of the Congo, May 2012.

Steve O. Taylor (GHF) / Men with vegetables in dugout wooden canoes on riverbank, Monkoto, Salonga National Park, Equateur, Democratic Republic of the Congo, May 2012.

Steve O. Taylor (GHF) / Man with vegetables in dugout wooden canoes on riverbank, Monkoto, Salonga National Park, Equateur, Democratic Republic of the Congo, May 2012.

Philip Stephen / Pelagic trawlers alongside at Symbister Harbour, Whalsay, Shetland Islands, November 2013. All non-editorial uses must be cleared individually.

Philip Stephen / Pelagic trawlers alongside at Symbister Harbour, Whalsay, Shetland Islands, November 2013. All non-editorial uses must be cleared individually.

Philip Stephen / Fishing vessel 'Antares' in Symbister Harbour, Whalsay, Shetland Islands, November 2013. All non-editorial uses must be cleared individually.

Philip Stephen / Pelagic fishing vessel 'Serene' moored in Symbister Harbour, Whalsay, Shetland Islands, November 2013. All non-editorial uses must be cleared individually.

Philip Stephen / Pelagic fishing vessels 'Charisma' and 'Serene' moored in Symbister Harbour, Whalsay, Shetland Islands, November 2013. All non-editorial uses must be cleared individually.

Philip Stephen / Part of the Shetland Pelagic fishing fleet tied up in Symbister Harbour, Whalsay, Shetland Islands, November 2013. All non-editorial uses must be cleared individually.