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

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...

Christophe Courteau / Velvet swimming crab portrait {Liocarcinus / Necora puber} Brittany France

Linda Pitkin / 2020VISION / Velvet Swimming Crab (Necora puber / Liocarcinus puber), St Abbs (St Abbs and Eyemouth Voluntary Marine Reserve), Berwickshire, Scotland, UK, October, 2011

Graham Eaton / Velvet swimming crab (Necora puber) pair mating, Trefor, Wales, UK, July.

David Hall / Swimmer crab (Lissocarcinus laevis) living commensally with Anemone (Actinodendridae). Pantar, Alor Archipelago, Indonesia.

Nick Upton / Velvet swimming crab (Necora puber) in a rock pool, hiding among Coralweed (Corallina officinalis), Cornwall, UK, March.

Nick Upton / Common shore crab (Carcinus maenas) hiding among Coralweed (Corallina officinalis) in a rock pool, Cornwall, UK, March.

Nick Upton / Close-up of a Common shore crab (Carcinus maenas) in a rock pool, vibrating its maxillae to aerate its gills and flicking its antennae, Cornwall, UK, March.

Nick Upton / Close-up of a Common shore crab (Carcinus maenas) in a rock pool, vibrating its maxillae to aerate its gills and flicking its antennae, Cornwall, UK, March.

Georgette Douwma / Xenia swimming crab (Caphyra sp(2. Lembeh Strait, North Sulawesi, Indonesia.

Nick Hawkins / Comparison of the invasive European green crab (Carcinus maenas) on left to native Atlantic rock crab (Carcinus irroratus) on right. Kejimkujik Seaside National Park, Nova Scotia, Canada. July.