John Shaw / Sally lightfoot crabs (Grapsus grapsus) on the beach at Puerto Egas, Santiago Island, Galapagos, May.

Andy Rouse / Sally lightfoot crab, (Grapsus grapsus), feeding on marine iguana parasites and dead skin, Galapagos

Nick Hawkins / European green crab (Carcinus maenas), an invasive species in North America, Kejimkujik Seaside National Park, Nova Scotia, Canada. July.

Nick Upton / Common prawns (Palaemon serratus) and a Rock goby (Gobius paganellus) feeding on a dead Montagu's crab (Xantho hydrophilus) in a rockpool, Cornwall, England, UK, September.

Nick Upton / Rock goby (Gobius paganellus) stealing food from a scavenging Common prawn (Palaemon serratus) in a rockpool, Cornwall, England, UK, September.

Sue Daly / Common lobster (Homarus gammarus) shovelling gravel out of a hole, Sark, British Channel Islands, UK, August.

Juergen Freund / Mud crab (Scylla serrata) in shallow sandy water. Split level with island and thatched house on stilts. Moromahu Island, Wakatobi, South Sulawesi, Indonesia. Second Place in the Portfolio Award of the...

Alex Mustard / Portrait of Sally lightfoot crab (Grapsus grapsus) on a beach. San Cristobal Island, Galapagos Islands, Ecuador. Tropical East Pacific Ocean.

Cyril Ruoso / Woman with baby collecting Madagascar periwinkle (Catharanthus roseus) flowers and leaves, used in herbal medicine, and containing molecules which are used in the treatment of leukemia cancer. Berenty...

Tui De Roy / Dead Sally-lightfoot crab (Grapsus grapsus) washed up in surf, Puerto Egas, James Bay, Santiago Island, Galapagos, Ecuador, May.

Christophe Courteau / Edible crab in tide pool split level {Cancer pagurus} Brittany France

Linda Pitkin / 2020VISION / Edible crab (Cancer pagurus), St Abbs (St Abbs and Eyemouth Voluntary Marine Reserve), Berwickshire, Scotland, UK, August 2011. Did you know? A large female Edible crab can carry up to 20 million eggs...