A reef shell lies on a beach as the sun sets on Lady Elliot Island located north-east of the town of Bundaberg in Queensland, Australia, June 10, 2015. UNESCO World Heritage delegates recently snorkelled on Australia’s Great Barrier Reef, thousands of coral reefs, which stretch over 2,000 km off the northeast coast. Surrounded by manta rays, dolphins and reef sharks, their mission was to check the health of the world's largest living ecosystem, which brings in billions of dollars a year in tourism. Some coral has been badly damaged and animal species, including dugong and large green turtles, are threatened. UNESCO will say on Wednesday whether it will place the reef on a list of endangered World Heritage sites, a move the Australian government wants to avoid at all costs, having lobbied hard overseas. Earlier this year, UNESCO said the reef's outlook was “poor”. (Photo by David Gray/Reuters)

Museum employee Victoria views a giant grouper fish specimen at the Natural History Museum in west London March 25, 2015. It forms part of a new exhibition, “Coral Reefs: Secret Cities of the Sea”, featuring a panoramic virtual dive and over 250 specimens from the Museum's coral, fish and marine invertebrate collection, which opens on March 27. (Photo by Toby Melville/Reuters)

In this May 2016 photo released by The Ocean Agency/XL Catlin Seaview Survey, a boat sails near a coral reef that has been bleached white by heat stress in the Maldives. oral reefs, unique underwater ecosystems that sustain a quarter of the world's marine species and half a billion people, are dying on an unprecedented scale. Scientists are racing to prevent a complete wipeout within decades. (Photo by The Ocean Agency/XL Catlin Seaview Survey via AP Photo)

“The Great Barrier Reef is one of the most important sea turtle habitats in the world, with Lady Elliot Island being a key part of that habitat. Every year between November and March the green and loggerhead turtles lumber up the same beach on which they were born more than 50 years ago. These turtles nest on Lady Elliot Island up to nine times in a season, laying between 80 and 120 eggs per clutch. About eight weeks later, young hatchlings leave their nests and head towards the ocean (January to April)”. – Wikipedia

Photo: A Hawksbill sea turtle is seen swimming on January 15, 2012 in Lady Elliot Island, Australia. (Photo by Mark Kolbe/Getty Images)

“7584 Fish”. On a windy day right after a Cyclone passed the far northern Great Barrier Reef i took some friends out to the reef. Never before i saw that many glass fish on this particular coral “bommie”. Just when i setup my camera, this Napoleon Wrasse swam right through the school of fish building a living frame. Photo location: Cairns, Great Barrier Reef, Flynn Reef, Australia. (Photo and caption by Christian Miller/National Geographic Photo Contest)

A Hawaiian cleaner wrasse provides its cleaning services to a yellowfin goatfish in a reef community off the Big Island in Hawaii. Cleaner species help rid their hosts of ectoparasites, dead tissue, bacteria and fungi. Studies have shown cleaning to play a vital role in keeping many reef ecosystems healthy. (Photo by Marty Snyderman/Caters News Agency)

An aerial view taken on March 8, 2021, shows Chinese fishing vessel Lurong Yuan Yu that ran aground on reefs of Pointe-aux-Sables in Port Louis, Mauritius, on March 7, 2021. (Photo by L'Express Maurice/AFP Photo)

South African surfer Andy Marr rides a wave at Dungeons offshore reef in the Atlantic Ocean outside Cape Town, South Africa, 01 September 2016. The big wave surfing season is at its peak with winter swells driven by storms in the South Atlantic breaking on the Cape's outer reefs providing good conditions. Big wave surfers are competing in the 2016 Striped Horse Challenge and Rebel Sessions big wave competitons symultaneously throughout the season. (Photo by Nic Bothma/EPA)