Alex Mustard / Grooved brain coral (Diploria labyrinthiformis) at night with polyps extended to feed, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea.

Nick Garbutt / Aggregation / bloom / swarm of Moon Jellyfish (Aurelia aurita) in the clear waters of Loch Na Keal, off the Isle of Mull, north west Scotland, UK, June, Photographed through the surface.

Franco Banfi / Floating, abandoned net in the ocean, Dominica, Caribbean Sea, Atlantic Ocean.

Franco Banfi / Sleeping sperm whale, (Physeter macrocephalus) Dominica, Caribbean Sea, Atlantic Ocean.

Franco Banfi / Sperm whale, (Physeter macrocephalus) Dominica, Caribbean Sea, Atlantic Ocean.

Franco Banfi / Pod of sperm whale socializing, (Physeter macrocephalus), Dominica, Caribbean Sea, Atlantic Ocean.

SCOTLAND: The Big Picture / Maiden's salp (Thetys vagina) , west coast of Scotland, UK, July.

Pedro Narra / West African mudskipper (Periophthalmus barbarus) Joao Vieira Poillo , Bijagos Archipellago. Guinea Bissau

Shane Gross / Nurse sharks (Ginglymostoma cirratum) two in a courtship dance at sunrise in a mangrove area near Eleuthera, Bahamas.

Shane Gross / Lemon shark pup (Negaprion brevirostris) in mangrove forest which acts as a nursery for juveniles of this species. Eleuthera, Bahamas.

Shane Gross / Lemon shark pup (Negaprion brevirostris) in mangrove forest which acts as a nursery for juveniles of this species. Eleuthera, Bahamas.

Shane Gross / Lemon shark pup (Negaprion brevirostris) in mangrove forest which acts as a nursery for juveniles of this species. Eleuthera, Bahamas.