Tony Wu / Twinspot snapper (Lutjanus bohar) shoal rushing up to spawn, releasing a cloud of milky white sperm and eggs in the water column. Caroline Islands, Palau, November.

Tony Wu / Twinspot snapper (Lutjanus bohar) engaged in a mass spawning aggregation early in the morning. Caroline Islands, Palau. April. Winner of Underwater category, Wildlife Photographer of the Year 2016.

Alex Mustard / Portrait of pair of Bohar snappers (Lutjanus bohar) in their spawning aggregation. Shark Reef, Ras Mohammed Marine Park, Sinai, Egypt. Red Sea.

Alex Mustard / Portrait of Bohar snappers (Lutjanus bohar) in its spawning aggregation. Shark Reef, Ras Mohammed Marine Park, Sinai, Egypt. Red Sea.

Claudio Contreras / Kelp bass / Rock sea bass (Paralabrax clathratus) and Giant kelp (Macrocystis pyrifera), Cedros Island, Pacific Ocean, Baja California, Mexico, May

Claudio Contreras / Kelp bass / Rock sea bass (Paralabrax clathratus) and Giant Kelp (Macrocystis pyrifera), Cedros Island, Pacific Ocean, Baja California, Mexico, May

Claudio Contreras / Kelp bass / Rock sea bass (Paralabrax clathratus) and Giant kelp (Macrocystis pyrifera) forest, San Benitos Islands, Baja California Pacific Islands Biosphere Reserve, Baja California, Mexico, May

Claudio Contreras / Kelp bass / Rock sea bass (Paralabrax clathratus) and Giant kelp (Macrocystis pyrifera) forest, San Benitos Islands, Baja California Pacific Islands Biosphere Reserve, Baja California, Mexico, May

Claudio Contreras / Kelp bass / Rock sea bass (Paralabrax clathratus) and Giant Kelp (Macrocystis pyrifera) forest, San Benitos Islands, Baja California Pacific Islands Biosphere Reserve, Baja California, Mexico, May

Alex Mustard / School of Bohar snapper (Lutjanus bohar) swimming in formation along a coral reef. These fish are usually solitary and aggregate each summer in the Red Sea to spawn. Ras Mohammed National Park, Sinai...

Alex Mustard / School of Bohar snapper (Lutjanus bohar) in open water above a coral reef. These fish are usually solitary and aggregate each summer in the Red Sea to spawn. Shark Reef, Ras Mohammed, Sinai, Egypt. Re...

Alex Mustard / School of Bohar snapper (Lutjanus bohar) in open water close to a coral reef. These fish are usually solitary and aggregate each summer in the Red Sea to spawn. Shark Reef, Ras Mohammed, Sinai, Egypt....

Alex Mustard / School of Bohar snapper (Lutjanus bohar) in open water close to a coral reef. Shark Reef, Ras Mohammed, Sinai, Egypt. Red Sea.

Alex Mustard / School of Bohar snapper (Lutjanus bohar) close to a coral reef. These fish are usually solitary and aggregate each summer in the Red Sea to spawn. Shark Reef, Ras Mohammed, Sinai, Egypt. Red Sea.

Alex Mustard / Bohar snappers (Lutjanus bohar) breaking up into smaller groups to spawn close to full moon. The fish swim short arches above the main group as they release clouds of gametes (eggs from the female, sp...

Alex Mustard / Large school of Bohar snappers (Lutjanus bohar) swimming in a tight, fast moving circular school over the reef, just before swimming into open water to spawn. Shark City, Ulong, Rock Islands, Palau. T...

Alex Mustard / Bohar snappers (Lutjanus bohar) breaking up into smaller groups to spawn close to full moon. The fish swim short arches above the main group as they release clouds of gametes (eggs from the female, sp...

Alex Mustard / Bohar snappers (Lutjanus bohar) breaking up into smaller groups to spawn close to full moon. The fish swim short arches above the main group as they release clouds of gametes (eggs from the female, sp...

Alex Mustard / Bohar snapper (Lutjanus bohar) school at Ras Mohammed, Shark Reef, Ras Mohammed, Sinai, Egypt. Red Sea.

Pascal Kobeh / Red snappers / Two-spot red snappers (Lutjanus bohar) mass shoal of fish spawning, Palau, Philippine Sea. A few black and white snappers (Macolor niger) have crawled into the school to eat the eggs.

Alex Mustard / School of Bohar snappers (Lutjanus bohar) above a coral reef. These fish are usually solitary but have gathered in the summer in the Red Sea for spawning. Shark Reef, Ras Mohammed Marine Park, Sinai,...

Alex Mustard / Bohar snappers (Lutjanus bohar) breaking up into smaller groups to spawn. The fish swim short arches above the main group as they release clouds of gametes. Shark City, Ulong, Rock Islands, Palau. T...

Alex Mustard / Bohar snapper (Lutjanus bohar) school with diver, Ras Mohammed, Ras Mohammed, Sinai, Egypt. Red Sea.

Alex Mustard / Large school of Bohar snappers (Lutjanus bohar) which have gathered in the summer in the Red Sea for spawning. Shark Reef, Ras Mohammed Marine Park, Sinai, Egypt. Red Sea.

Alex Mustard / School of Bohar snappers (Lutjanus bohar) Shark Reef, Ras Mohammed Marine Park, Sinai, Egypt. Red Sea.

Alex Mustard / Portrait of the, normally solitary Bohar snapper (Lutjanus bohar) in an annual spawning aggregation in June. Ras Mohammed Marine Park, Sinai, Egypt. Red Sea.

Alex Mustard / The vertical reef wall at Shark Reef, Ras Mohammed, with Scalefin anthias (Pseudanthias squamipinnis) and soft corals (Dendronephthya spp.) Yellowsaddle goatfish (Parupeneus cyclostomus) and school of...

Alex Mustard / School of Bohar snappers (Lutjanus bohar), moving along the face of reef. These fish are up to 80cm in length and normally solitary, but have gathered in summer in spawning aggregation. Shark Reef, Ra...

Alex Mustard / Large school of Bohar snappers (Lutjanus bohar) which have gathered in the summer in the Red Sea for spawning. Each fish is between 60 and 80cm long. Shark Reef, Ras Mohammed Marine Park, Sinai, Egypt...

Alex Mustard / School of large Bohar snappers (Lutjanus bohar) gathered in spawning aggregation off Ras Mohammed, Sinai, Egypt. Red Sea.

Alex Mustard / Large school of Bohar snappers (Lutjanus bohar) gather with smaller shoal of Batfish (Platax orbicularis) in open water off Ras Mohammed at the tip of Sinai, Egypt. These schools gather only in summer...

Alex Mustard / School of Batfish (Platax orbicularis) in front of Bohar snappers (Lutjanus bohar) as the wall at Shark Reef, Ras Mohammed Marine Park, Sinai, Egypt. Red Sea.

Graham Eaton / Bass (Dicentrarchus labrax) above kelp. Cardigan Bay, Wales, July.

Richard Herrmann / Kelp Bass (Paralabrax clathratus) group near Southern Sea Palm (Eisenia arborea), San Clemente Island, Channel Islands, California

GEORGETTE DOUWMA / Kelp bass {Paralabrax clathratus} in Giant kelp forest {Macrocystis pyrifera} California, USA.

Jeff Rotman / Kelp bass fish closeup of eye {Paralabrax clathratus} California, Pacific

Ralph Pace / Kelp Bass (Paralabrax clathratus) group in kelp forest, San Diego, California

Ralph Pace / Kelp Bass (Paralabrax clathratus) in kelp forest, San Diego, California

Ralph Pace / Kelp Bass (Paralabrax clathratus) school, San Diego, California

Ralph Pace / Kelp Bass (Paralabrax clathratus), San Diego, California

Ralph Pace / Kelp Bass (Paralabrax clathratus) school, San Diego, California

Ralph Pace / Giant Sea Bass (Stereolepis gigas), San Diego, California

Bernard Castelein / North Berwick beach at low tide with seaweeds. Scotland UK. Bass rock in background.

Noemie Stroh / Red snapper (Lutjanus bohar) aggregation during mating season, Ras Mohamed National Park, Red Sea, Egypt. July.

Alex Mustard / Schools of fish, including Bohar snappers (Lutjanus bohar), Yellow-spotted trevally (Carangoides orthogrammus) and Bigeye trevally (Caranx sexfasciatus) gathering adjacent to a colourful coral reef wi...

Russell Laman / Giant sea bass (Stereolepis gigas) and Kelp bass (Paralabrax clathratus) swimming amongst Giant kelp (Macrocystis pyrifera) forest off Catalina Island, California, USA, Pacific Ocean. Critically endan...

Russell Laman / Two Giant sea bass (Stereolepis gigas) chasing each other amongst the Giant kelp (Macrocystis pyrifera) forest off Catalina Island, California, USA, Pacific Ocean. Critically endangered.

Russell Laman / Giant sea bass (Stereolepis gigas) resting amongst the Giant kelp (Macrocystis pyrifera) forest off Catalina Island, California, USA, Pacific Ocean. Critically endangered.

Russell Laman / Giant sea bass (Stereolepis gigas) swimming amongst the Giant kelp (Macrocystis pyrifera) forest off Catalina Island, California, USA, Pacific Ocean. Critically endangered.

Henley Spiers / Red snapper (Lutjanus bohar) in foreground and other reef fish in background including Napoleon wrasse (Cheilinus undulatus) feeding on discarded fish, Misool, Raja Ampat, Indonesia, Pacific Ocean

Tony Wu / Reef manta ray (Mobula alfredi) swimming with a Twinspot snapper (Lutjanus bohar), Okinawa, Japan, Pacific Ocean.

David Fleetham / Kelp bass (Paralabrax clathratus) in Giant kelp (Macrocystis pyrifera) forest, Santa Barbara, California, USA.

Alex Mustard / Red gorgonian (Lophogorgia chilensis) grows beneath a forest of Giant kelp (Macrocystis pyrifera), with kelp bass (Paralabrax clathratus). Santa Barbara Island, Channel Islands. Los Angeles, Californi...