Green shore crab

Latin name - Carcinus maenas  Size - Shell up to 8cm wide  Habitat - Mid shore and rockpools

These crabs will scavenge for food but also eat shrimps, worms, mussels and various other shelled animals which they break apart with their powerful claws. The edge of the crab’s shell is serrated with teeth-like points, which helps to distinguish them from other species.

Edible crab

Latin name - Cancer pagurus  Size - Shell up to 25cm wide  Habitat - Young crabs live on the lower shore and adults live further out to sea

The shell of this crab has a distinctive pie-crust edge and black-tipped claws.  It uses these extremely powerful claws to crush the shells of the animals that it preys upon.  This crab is caught by fishermen and gets its name because it is nice to eat!

Velvet swimming crab

Latin name - Necora puber  Size - Shell up to 8cm wide  Habitat - Lower shore under rocks and stones

The shell is covered in short hairs which creates a velvety appearance and gives this crab its name. Its back legs are flattened out like paddles, which make them better for swimming. Also known as the Devil crab, it has bright red eyes and a painful nip.

Hermit crab

Latin name - Pagarus bernhardus  Size - Shell up to 3.5cm long  Habitat - All over the shore and deep water

Unlike other crabs, the hermit crab doesn’t have a hard shell to protect itself. Instead it uses an empty sea snail shell, such as a winkle or whelk shell, as a home. Its two back legs have adapted into hooks so that it can anchor itself within the shell. As the crab grows it finds a bigger shell to move into.

Common Blenny

Latin name - Lipophrys pholis  Size - Up to 16cm long  Habitat - Rockpools

These fish are very well adapted for the seashore environment. Instead of having scales, blennies are coated in slime to keep them damp. They can also change the colour of their skin to blend in with the rocks and seaweed around them. Their sharp teeth are used for crunching barnacles off rocks and they also eat other small animals and seaweed too.

Rock Goby

Latin name - Gobius paganellus  Size - Up to 13cm long  Habitat - Middle and lower shore rock pools

The goby can look quite similar to the blenny. The easiest way to tell them apart is the fin along their back (dorsal fin). The goby has two distinct fins, whereas the blenny has one. The fins on the underside of the goby are fused together to form a sucker that holds onto rock and stops it from being washed away by the waves.

Beadlet anemone

Latin name - Actinia equina  Size - Column up to 5cm tall plus tentacles up to 2cm long  Habitat - All over the rocky shore

These anemones can retract their tentacles and store water which stops them from drying out at low tide. When they are covered by seawater they extend their poisonous tentacles which they use to catch prey such as prawns and small fish. They will also sting another anemone if it gets too close. They get their name from the bright blue beads around the edge of the tentacles.

Snakelocks anemone

Latin name - Anemonia viridis  Size - Column up to 5cm tall plus tentacles up to 15cm long  Habitat - Mid shore attached to rock

The snakelocks anemone does not retract its tentacles like the beadlet anemone and so it would quickly dry up out of water. To avoid this it lives further down the shore and in rockpools. It uses its long poisonous tentacles for feeding and protection.

Common Limpet

Latin name - Patella vulgata  Size - Shell up to 6cm long  Habitat - All over the rocky shore

Limpets have a strong muscular foot which allows them to hold on tightly to rocks. At low tide, the limpet will clamp its shell down tight to prevent itself from losing water and drying out. This also stops them from being pulled off the rocks by birds and other predators. When the tide is in the limpets move over the rocks and use a rough tongue (radula) to feed on algae before returning home to the same place on the rock.

Common Acorn Barnacle

Latin name - Semibalanus balanoides  Size - Up to 1.5 cm diameter  Habitat - Mid and lower shore on rock

Barnacles start their life in the sea as plankton and then settle on a hard surface (usually rock but sometimes piers or boats) where they stay for the rest of their life. They grow plates around them to protect their body. To feed, they extend their feathery legs to catch plankton in the seawater.

Flat Topshell

Latin name - Gibbula umbilicalis  Size - Up to 1.5cm tall   Habitat - All over the rocky shore

These sea snails look just like the snails that live on land but they can breathe underwater. They feed on algae that grow on rock. There are many other species of topshell that live on our shores including the grey and painted topshell.

Dog whelk

Latin name - Nucella lapillus  Size - Up to 4cm tall  Habitat - All over the rocky shore

Dog whelks are carnivorous (meat eating) sea snails. They drill holes in the shells of other creatures such as limpets and barnacles and turn the creature into soup before using their tongue to suck it all up. The colour of the shell varies depending on what the dog whelk eats.

Common Prawn

Latin name - Palaemon serratus   Size - Up to 11cm long   Habitat - Rockpools and up to depths of 40m

Prawns are scavengers, feeding on scraps left from other animal’s meals and so are known as the cleaners of the rockpool. They have a see through body which makes them difficult to spot. The best way to tell the difference between a prawn and a shrimp is that prawns have stripes and shrimps have spots.

Sea urchin

Latin name - Psammechinus miliaris  Size - Up to 5cm diameter  Habitat - Mid and lower shore

Sea urchins have a hard spiny skeleton which helps to protect them from predators. Amongst the spines are tiny tube feet which the animal uses to move around. Its mouth is located on the underside of the creature and it has 5 large teeth, which it uses to graze on plants like algae. These teeth make up the Sea urchin’s jaw which is known as Aristotle’s lantern. Sea urchins are a close relative of starfish.

Common Starfish

Latin name - Asterias rubens  Size - Up to 50cm across  Habitat - Lower shore rockpools and deeper water

The starfish has a toughened thick skin that protects its body. It feeds on animals like mussels and clams and will arch over its prey and then open the shell with its tube feet. It then pushes its stomach into the shell, where it will then eat its meal.
(Photo by Hans Hillewaert. This starfish was sampled on the Belgian Continental Shelf in 2000.)