Tony Wu / Female Northern pygmy squid (Idiosepius paradoxus) depositing eggs on a blade of eelgrass (Zostera marina), Yamaguchi Prefecture, Japan.

Tony Wu / Female Northern pygmy squid (Idiosepius paradoxus) preparing to lay another egg on a blade of eelgrass (Zostera marina), Yamaguchi Prefecture, Japan.

Shane Gross / Dugong (Dugong dugon) feeding on Tapegrass (Halophila stipulacea), accompanied by juvenile Golden trevally fish (Gnathanodon speciosus). Marsa Alam, Egypt.

Shane Gross / Dugong (Dugong dugon) male and juvenile Golden trevally (Gnathanodon speciosus) shoal swimming over Turtlegrass (Halophila stipulacea) seagrass bed. Marsa Alam, Egypt.

Shane Gross / Cunner (Tautogolabrus adspersus) pair in Eelgrass (Zostera marina) bed. Newfoundland, Canada. September.

Alex Mustard / Leafy seadragon (Phycodurus eques) male carrying eggs, swims over seagrass meadow. Wool Bay, Edithburgh, South Australia. Gulf of St Vincent.

Shane Gross / Green turtle (Chelonia mydas) feeding on Turtlegrass (Thalassia testudinum) seagrass bed. The Bahamas.

Alex Mustard / Dugong (Dugong dugon) male, swims over seagrass meadow (Halophila stipulacea) accompanied by a young Golden trevally (Gnathanodon speciosus). Marsa Nabaa, Marsa Alam, Egypt. Red Sea

Alex Mustard / Dugong (Dugong dugon) male feeding on a seagrass meadow (Halophila stipulacea), accompanied by a young Golden trevally (Gnathanodon speciosus). Marsa Nabaa, Marsa Alam, Egypt. Red Sea

Alex Mustard / Dugong (Dugong dugon) male feeding on a seagrass meadow (Halophila stipulacea), accompanied by a young Golden trevally (Gnathanodon speciosus). Marsa Nabaa, Marsa Alam, Egypt. Red Sea

Dimitris Poursanidis / Neptune seagrass meadow (Posidonia oceanica) in the coastal zone of the Samaria National Park, Chania, Crete

Dimitris Poursanidis / Abandonded fishing gear in seagrass meadow, with red sea squirt (Halocynthia papillosa), Samaria National Park, Chania, Crete, Greece

Dimitris Poursanidis / Abandonded fishing gear in seagrass meadow (Posidonia oceanica), Agia Pelagia, Heraklion, Crete, Greece

Alex Mustard / Dugong (Dugong dugon) male and juvenile Golden trevally (Gnathanodon speciosus) swimming over Seagrass (Halophila stipulacea) meadow. Marsa Nabaa, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) feeding on Seagrass (Halophila stipulacea), blowing sand out of nostrils, on sea floor. Marsa El Shouna, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) resting on sea floor and two juvenile Golden trevally (Gnathanodon speciosus). Marsa El Shouna, Marsa Alam, Egypt.

Nick Hawkins / American lobster (Homarus americana) in eelgrass (Zostera marina). Nova Scotia, Canada. July

Shane Gross / Queen conch (Lobatus gigas) juvenile feeding on algae growing on Seagrass (Thalassia testudinum) blades. Eleuthera, Bahamas.

Shane Gross / American crocodile (Crocodylus acutus) with open mouth amongst Seagrass (Alismatales). Gardens of the Queen National Park, Cuba.

Claudio Contreras / American crocodile (Crocodylus acutus) rear view of animal swimming away over seagrass bed, Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico

Claudio Contreras / American crocodile (Crocodylus acutus) exhaling bubbles underwater, Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico, May.

Claudio Contreras / American crocodile (Crocodylus acutus) split level with animal resting at surface in shallow water over seagrass bed, Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico

Claudio Contreras / American crocodile (Crocodylus acutus) rear view of animal resting in shallow water, close up of tail, Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico

Claudio Contreras / American crocodile (Crocodylus acutus) resting just above seagrass underwater, Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico

Claudio Contreras / American crocodile (Crocodylus acutus) extreme close up with jaws open, Banco Chinchorro Biosphere Reserve, Caribbean region, Mexico

Pascal Kobeh / Long-snouted seahorse (Hippocampus guttulatus) with prehensile tail twined round seagrass, Etang de Thau Lagoons, Languedoc-Roussillon, France.

Cheryl-Samantha Owen / Looking down on sea grass, Aldabra Atoll, Seychelles, Indian Ocean

Alex Mustard / 2020VISION / A captive Yellow / Spiny seahorse (Hippocampus guttulatus) attached to plastic seagrass, Weymouth Sealife Centre, Dorset, England, UK.

Alex Mustard / A Leafy Seadragon (Phycodurus eques) swims over a seagrass bed. Wool Bay Jetty, Edithburgh, Yorke Peninsular, South Australia, November.

Alex Mustard / A male Spiny Seahorse (Hippocampus guttulatus) hides in seagrass. Etang De Thau (Thau Lagoon), Montpellier, France, Europe, September.

Alex Mustard / A young Spiny / Yellow / Longsnouted Seahorse (Hippocampus guttulatus), in an aquarium attached to plastic seagrass leaves. This seahorse is part of a UK seahorse breeding program. Photographed at the...

Juergen Freund / Split-level shot of a pet baby Hawksbill turtle (Eretmochelys imbricata) swimming in the shallows. Tunnung Island, New Hanover, Papua New Guinea, June 2010.

Juergen Freund / Dugong (Dugong dugon) in the seagrass bed shadowed by a trevally. Dimakya Island, Palawan, Philippines

Juergen Freund / Diver watching a swimming Dugong (Dugong dugon). Dimakya Island, Palawan, Philippines, April 2010.

Juergen Freund / Dugong (Dugong dugon) feeding in the seagrass bed with trevally fish inspecting the disturbed sand. Dimakya Island, Palawan, Philippines

Onne van der Wal / Young man snorkeling over seagrass bed, holding a starfish, The Grenadines, Caribbean. February 2010, Model released.

Onne van der Wal / Green turtle (Chelonia mydas) swimming over sea grass, Grenadines, Caribbean, February 2010.

Claudio Contreras / Cushion sea star (Oreaster reticulatus) on Turtle grass (Thalassia testudinum) Banco Chinchorro Biosphere Reserve, Caribbean Sea, Mexico, July

Juergen Freund / Saltwater crocodile (Crocodylus porosus) swimming at water surface, split-level, New Guinea, Indo-pacific

Wild Wonders of Europe / Pitkin / Dusky Grouper (Epinephelus marginatus) by seagrass, Endangered, Cala di Grecu, Lavezzi Islands, Corsica, September 2008 WWE Mission: Lavezzi Island Reserve, Corsica

Doug Perrine / Pair of Robust ghost pipefish {Solenostomus cyanopterus} mimicing seagrass, Mabul Island, Sabah, Malaysia

Doug Perrine / Bottlenose dolphin {Tursiops truncatus} swimming over seagrass, Belize

Jose B. Ruiz / Neptune seagrass {Posidonia oceanica} forms large prairies of grass in well lit seabeds. Mediterranean

Juergen Freund / Dugong grazing on sea grass {Dugong dugon} Indo Pacific

Juergen Freund / Dugong grazing on sea grass {Dugong dugon} Indo Pacific

Norbert Wu / Seagrass beds serve as sediment traps and nurseries, Palau