Alex Mustard / California sea lion (Zalophus californianus) adult female swimming through sunbeams in an underwater cave. Los Isotes, La Paz, Mexico. Sea of Cortez, East Pacific Ocean.

Alex Mustard / Boulder brain coral (Colpophyllia natans) photographed with a long exposure with camera rotation. Taken with circular fisheye lens. Grand Cayman, Cayman Islands. Caribbean Sea.

Alex Mustard / Great white shark (Carcharodon carcharias) from above. Guadalupe Island, Baja California, Mexico. East Pacific Ocean

Alex Mustard / Nudibranchs (Doto greenamyeri) newly described species on feather hydroids. Seraya Bay, north coast of Bali, Indonesia. Java Sea.

Alex Mustard / Harbour seal (Phoca vitulina) in the kelp forest (Macrocystis pyrifera). Santa Barbara Island, Channel Islands. Los Angeles, California, United States of America. North East Pacific Ocean.

Alex Mustard / Leafy seadragon (Phycodurus eques). Wool Bay Jetty, Edithburgh, Yorke Peninsula, South Australia.

Alex Mustard / Spotlight goby (Gobiosoma louisae) looking out from inside a Yellow tube sponge (Aplysina fistularis), growing on a coral reef. Bloody Bay Wall, Little Cayman, Cayman Islands, British West Indies. Car...

Alex Mustard / Nassau grouper (Epinephelus striatus) yawning on a coral reef drop off. San Salvador island, Bahamas. Bahamas Sea, Tropical West Atlantic Ocean.

Alex Mustard / Great white sharks (Carcharodon carcharias) males beneath the surface. Guadalupe Island, Baja California, Mexico. East Pacific Ocean

Alex Mustard / California sea lion (Zalophus californianus) resting in the canopy of a forest of giant kelp (Macrocystis pyrifera). Santa Barbara Island, Channel Islands. Los Angeles, California, United States of Am...

Alex Mustard / Portrait of a Nudibranch (Flabellina pellucida) on a kelp frond with star trails. Gulen, Norway. North East Atlantic Ocean.

Alex Mustard / Lion's mane jellyfish (Cyanea capillata) with feeding tentacles spread swimming in the sun in shallow water. Gulen, Norway. North East Atlantic Ocean.