Michel Roggo / Watermilfoil (Myriophyllum spicatum) with some stems supporting clusters of Zebra mussel (Dreissena polymorpha) Lake Neuchatel, Switzerland. Highly commended in the Plants category of the Wildlife Pho...

Gary Bell/ Oceanwide / Bigfin Reef Squid (Sepioteuthis lessoniana) at night, Milne Bay, Papua New Guinea

Gary Bell/ Oceanwide / Bigfin Reef Squid (Sepioteuthis lessoniana) at night, Milne Bay, Papua New Guinea

Gary Bell/ Oceanwide / Bigfin Reef Squid (Sepioteuthis lessoniana) juvenile at night, Anilao, Philippines

Gary Bell/ Oceanwide / Veined Octopus (Octopus marginatus), Anilao, Philippines

Gary Bell/ Oceanwide / Veined Octopus (Octopus marginatus) hiding in bottle, Anilao, Philippines

Gary Bell/ Oceanwide / Wonderpus Octopus (Wunderpus photogenicus), Anilao, Philippines

Gary Bell/ Oceanwide / Wonderpus Octopus (Wunderpus photogenicus), Anilao, Philippines

Gary Bell/ Oceanwide / Wonderpus Octopus (Wunderpus photogenicus), Anilao, Philippines

Gary Bell/ Oceanwide / Veined Octopus (Octopus marginatus) predating urchin, Anilao, Philippines

Gary Bell/ Oceanwide / Veined Octopus (Octopus marginatus) hiding in glass jar, Lembeh Strait, Indonesia

Gary Bell/ Oceanwide / Australian Giant Cuttlefish (Sepia apama) group gathered for mating, Whyalla, South Australia, Australia

Gary Bell/ Oceanwide / Australian Giant Cuttlefish (Sepia apama) male and female, Whyalla, South Australia, Australia

Gary Bell/ Oceanwide / Australian Giant Cuttlefish (Sepia apama) males fighting over female, Whyalla, South Australia, Australia

Gary Bell/ Oceanwide / Australian Giant Cuttlefish (Sepia apama) males fighting over female, Whyalla, South Australia, Australia

Theo Bosboom / Common limpets (Patella vulgata) hit by a big wave from the Atlantic ocean at the coast of Crohy head, Donegal, Ireland. November 2017

Alex Mustard / Free swimming mimic octopus (Thaumoctopus mimicus). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Free swimming mimic octopus (Thaumoctopus mimicus). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Veined octopus (Amphioctopus marginatus) shelters inside an old clam shell, with silver-sides in the water above. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Veined octopus (Amphioctopus marginatus) emerging from its home in an old clam shell. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Shoal of three Bigfin reef squid (Sepioteuthis lessoniana) in open water at night. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Nigel Cattlin / Eggs of Golden apple snail / Channelled apple snail (Pomacea caniculata) in a Rice (Oryza sativa) paddy, Luzon, Philippines

Shane Gross / Larval Wonderpus octopus (Wunderpus photogenicus) drifting in the open ocean at night off Anilao, Philippines.

Shane Gross / Wonderpus octopus (Wunderpus photogenicus) in its juvenile or larval stage. At this stage it is transparent and drifts in the open ocean as plankton. Anilao, Philippines.

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

Georgette Douwma / Nudibranch (Chromodoris willani) with a scale worm. Lembeh Strait, North Sulawesi, Indonesia.

SCOTLAND: The Big Picture / Blue mussels (Mytilus edulis) with encrusting marine life, Sula Sgeir, Scotland. UK, July

SCOTLAND: The Big Picture / Curled octopus (Eledone cirrhosa) amongst a horse mussel bed (Modiolus modiolus) Shetland, Scotland, UK, August.

Shane Gross / A small aggreggation of queen conch (Lobatus gigas) off Cat Island, Bahamas

Shane Gross / Queen conch (Lobatus gigas) laying eggs in the Exuma Cays Land and Sea Park, Exuma, Bahamas.

Georgette Douwma / Mantel of Spiny oyster (Spondylus varius). Indonesia. Indo-West Pacific.

John Chan / Western gull (Larus occidentalis) feeding on a California two-spot octopus (Octopus bimaculoides) on a mudflat at low tide, Southern California, USA, November.

Philippe Clement / Lined top shells (Phorcus lineatus) in a rock pool, Normandy, France, June

Philippe Clement / Lined top shells (Phorcus lineatus) and Common european limpets (Patella vulgata) in a rock pool, Normandy, France, June.

David Fleetham / Day / Big blue octopus (Octopus cyanea) with diver in background. Hawaii. September 2012.

Juergen Freund / Timelapse of Periwinkle snails (Littoraria) climbing up Mangrove (Rhizophora) roots at lowtide, Daintree, Wet Tropics World Heritage Area, North Queensland, Australia.

Juergen Freund / Timelapse of Giant sea cucumbers (Thelenota ananas) moving underwater, with a Giant clam (Tridacna gigas) in the background, Great Barrier Reef, Queensland, Australia, 2015.

Steve Downer / Juvenile Common frog (Rana temporaria) on back of a Common snail (Cornu aspersum), UK, June.

Steve Downer / Juvenile Common frog (Rana temporaria) on back of a Common snail (Cornu aspersum), UK, June.

Alex Hyde / Colony of Common Mussels (Mytilus edulis) growing on striated rock formation exposed at low tide. Cornwall, England, UK. Highly commended in the Coast and Marine Category of the British Wildlife Photo...

Theo Bosboom / Limpets (Patellidae) exposed at low tide on the coast of Playa de Ursa, Portugal. Finalist in the Animals in their Environment Category of the Wildlife Photographer of the Year Awards (WPOY) Competiti...

Brian Bevan / Two Giant african snails (Achatina fulica) emerging from their shells and looking around, UK. Captive.

John Waters / Timelapse of flies and a slug on a Common stinkhorn fungus (Phallus impudicus), Mendips, Somerset, UK, July.

Steve Downer / Close up of a Black slug (Arion ater agg.) feeding on a Plantain lily (Hosta) leaf, Birmingham, England, UK, August.

Steve Downer / Black slug (Arion ater agg.) feeding on a dead Yellow slug (Limax flavus), Birmingham, England, UK, August.

Steve Downer / Grove snail / brown lipped snail (Cepaea nemoralis) with juvenile riding on its back, Birmingham UK June.

Steve Downer / Yellow slug (Limax flavus) back lit embryo moving around in egg case.

Steve Downer / Slug (Species unknown) descending on slime rope from leaf. UK. June.

Steve Downer / Yellow slug (Limax maximus) moving across bridge over road with traffic in the background. Birmingham, UK. June.

Steve Downer / Black arion slug (Arion ater) moving, viewed from beneath showing ripples or pedal waves used for locomotion.

Steve Downer / Yellow slug larva (Limax flavus) emerging from an egg case, controlled conditions.

Steve Downer / Yellow slug larva (Limax flavus) emerging from an egg case, controlled conditions.

Steve Downer / Newly hatched slug (Gastropoda) approaching a water droplet on a leaf before bursting it and retracting its eyestalks, Birmingham, England, UK. Controlled conditions.

Steve Downer / Banded snail (Cepaea nemoralis) on rear of a backlit rose leaf, controlled conditions.

Konrad Wothe / Giant snail (Megalobulimus) in a lowland rainforest, Panguana Reserve, Huanuco Region, Peru.

Sue Daly / Common cuttlefish (Sepia officinalis) hunting, filmed at night, Sark, British Channel Islands, UK, August.

Sue Daly / Common cuttlefish (Sepia officinalis) hunting, filmed at night, Sark, British Channel Islands, UK, August.

Sue Daly / Common cuttlefish (Sepia officinalis) hunting, filmed at night, Sark, British Channel Islands, UK, August.

Sue Daly / Common cuttlefish (Sepia officinalis) hunting, filmed at night, Sark, British Channel Islands, UK, August.

Ammonite / Close up of a Common snail (Cornu aspersum) moving, with Woodlice (Oniscidea). Controlled conditions.

Alex Mustard / Veined octopus (Amphioctopus marginatus) sheltering in an old clam shell, with plankton swirling around it at night (captured as trails in the long exposure). Bitung, North Sulawesi, Indonesia. Lembeh...

Ingo Arndt / Land snail / Brown-lipped snail (Cepaea nemoralis) crawling over a razor blade. The constantly produced mucus is a protection shield between the sole of the snail and the razor blade whilst the snail...

Ingo Arndt / Land snails (Polymita picta) shells, Cuba. Endemic species.

Ingo Arndt / Land snail (Polymita picta) collection of shells showing variation in patterning, Cuba. Endemic species.

SCOTLAND: The Big Picture / European river otter (Lutra lutra) female bringing octopus ashore for cub, Shetland, Scotland, UK, October.

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

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

Luis Quinta / Body of deep sea squid floating near the surface, with mantle ripped up possibly by cetaceans such as Sperm whales which are present in the region, Pico Island, Azores, Portugal, May.

Pascal Kobeh / Pygmy cuttlefish (Sepia sp.) Indonesia, Sulawesi Sea.

Franco Banfi / Humboldt squid (Dosidicus gigas) attracted to 'squid jig' bait which glows at night off Loreto, Sea of Cortez, Baja California, Mexico, East Pacific Ocean.

Franco Banfi / Humboldt squid (Dosidicus gigas) at night off Loreto, Sea of Cortez, Baja California, Mexico, East Pacific Ocean.

Franco Banfi / Scuba diver and Humboldt squid (Dosidicus gigas) at night off Loreto, Sea of Cortez, Baja California, Mexico, East Pacific Ocean. August 2007.

Franco Banfi / Humboldt squid (Dosidicus gigas) cannibalising another squid of the same species at night off Loreto, Sea of Cortez, Baja California, Mexico, East Pacific Ocean.

Franco Banfi / Humboldt squid (Dosidicus gigas) at night off Loreto, Sea of Cortez, Baja California, Mexico, East Pacific Ocean.

Franco Banfi / Mexican fisherman boat at dusk, fishing Humboldt squid (Dosidicus gigas) , at night off Santa Rosalia, Sea of Cortez, Baja California, Mexico, East Pacific Ocean.

Franco Banfi / Beak and tentacles of Humboldt squid (Dosidicus gigas) at night off Loreto, Sea of Cortez, Baja California, Mexico, East Pacific Ocean.

Franco Banfi / Pacific octopus (Octopus dofleini) Vancouver Island, British Columbia, Canada, Pacific Ocean

Alex Mustard / Nudibranch (Flabellina lineata) in aquarium, taken in the field in Gulen, Norway. North East Atlantic Ocean. Collected for scientific research.

Alex Mustard / Bigfin squid (Sepioteuthis lessoniana) hovering in mid water at night. Anilao, Batangas, Luzon, Philippines. Verde Island Passages, Tropical West Pacific Ocean.

Alex Mustard / Nudibranch (Nembrotha cristata) climbing on a Tunicate (Polycarpa aurata) at night. This species of seaslug feeds on seasquirts. A tiny cyclopoid copepod swimming past. Yillet Yecil, Yillet Islands, M...

Alex Mustard / Portrait of Bigfin squid (Sepioteuthis lessoniana) hovering in open water above a coral reef at night. Dampier Strait, Raja Ampat, West Papua, Indonesia. Tropical West Pacific Ocean

Alex Mustard / Caribbean reef squid (Sepioteuthis sepioidea) amongst gorgonians, on a shallow coral reef. Cayman Brac, Cayman Islands. Caribbean Sea.

Alex Mustard / Reef octopus (Octopus cyanea) portrait near wreck. Gubal Island, Egypt. Red Sea.

Mark MacEwen / Firefly squid (Watasenia scintillans) close to beach during mating season. Toyama Bay, Japan.

Solvin Zankl / Deepsea Octopus (Bathypolypus bairdii) specimen from the North Atlantic, near the Faroe Islands at a depth of 805m

Konrad Wothe / Giant land snail (Megalobulimus sp), Panguana Reserve, Huanuco province, Amazon basin, Peru.

Georgette Douwma / Cock's comb oyster (Lopha cristagalli) covered with encrusting sponge on artificial reef. Mabul, Malaysia.

Juergen Freund / Bigfin reef squid (Sepioteuthis lessoniana) blurred motion photograph, Kimbe Bay, West New Britain, Papua New Guinea.

Juergen Freund / Giant clam (Tridacna gigas) Raja Ampat, West Papua, Indonesia.

Juergen Freund / Chambered nautilus (Nautilus pompilius) with red whip coral. Osprey Reef, Great Barrier Reef, Queensland, Australia.

Pascal Kobeh / Giant clam (Tridacna) on 'Lotus' artificial reef, built in 2001 with a steel frame using mild electric currents to encourage coral growth, with diver in the background. Vabbinfaru Island in North Male...

Constantinos Petrinos / Bigfin reef squid (Sepioteuthis lessoniana) schooling parallel to one another. Lembeh Strait, North Sulawesi, Indonesia.

Constantinos Petrinos / Chromodorid nudibranch (Chromodoris annae) on Sea Squirt (Polycarpa aurata) Lembeh Strait, North Sulawesi, Indonesia.

Aflo / Deep sea squid (Chiroteuthis imperator) dead specimen floating, Osezaki, Shizuoka, Izu, Japan.

Ron Bielefeld / Snail Kite (Rostrhamus sociabilis) male flying with snail prey, Florida

Ron Bielefeld / Snail Kite (Rostrhamus sociabilis) male flying with snail prey, Florida