Seaweeds

Greens

Sea lettuce Found on the upper shore and in rock pools.

Good indicator of fresh water input into the marine environment, as it can tolerate a wide range of

salinities.

Gut weed

Found on the upper shore and in areas of fresh water input.

Can tolerate a wide range of salinities and is very tolerant to drying out, hence it settles widely on the rocky shore.

Browns

Saw wrack

Found on the upper-mid shore. Characterised by tooth-like notches on its fronds.

Rocky shore field ID guide: Common UK species

Bladder wrack

Found on the mid-lower shore. Has smooth fronds characterised by a pair of air bladders. Has a strong holdfast which prevents in from being washed away by the tide.

Spiral wrack

Found on the high shore. Has ridged branching fronds with no air bladders.

Egg wrack

Found on the mid shore. Long fronds with large egg-shaped air bladders.

Channelled wrack

Found on the high shore. Short channelled fronds with two small branches

extending from each.

Kelp

Found on the lower shore. Characterised by long solid stipes and large leathery

fronds. Has a strong holdfast which prevents it from being

washed away by the tide.

Reds

Coral weed

Found on the lower shore and in rock pools. Has calcium carbonate segments which protects it against grazers.

Irish moss

Found on the mid-lower shore and in rock pools.

Adapts to drying out by settling under or near canopy forming species such as bladder wrack and tooth wrack.

Dulse

Found on the lower shore, often attached to kelp stipes, Dulse is characterised by wide, flat and ribbon-like fronds.

Pepper dulse

Usually found on the mid-lower shore, Pepper dulse is characterised by short tips with feathered branches, similar in appearance to ‘little

Christmas trees’.

Ceramium

Grows on other seaweeds and in rock pools. Forms in tufts with fine filaments.

Purple laver

Usually found on the mid-upper shore, particularly if there is sand present. Grows in slimy sheets across the rocky shore.

Used in the production of Welsh laver bread.

Lichens

Black tar lichen Lichens are formed by a mutually beneficial relationship between algae and fungi. Occur on open rock and come in a range of colours.

Animals Breadcrumb sponge

Sponges are formed by a colony of microscopic, single celled animals.

Found on open bedrock, boulders and in crevices.

Limpets

Marine snails found in greatest abundance on the mid-shore. Limpets don’t move during low tide where they settle in ‘homescars’ to minimise water loss. During high tide, limpets actively graze on algae before returning back to their homescar to wait out the low tide.

Barnacles

Barnacles are small animals which live in colonies on open bedrock and boulders.

They have an ‘operculum’, or trap door to reduce water loss during low tide. By living in colonies, barnacles are able to regulate the

temperature of the environment around them, reproduce, and collectively filter feed without moving for their entire lives once settled out on the shore.

Dog whelk

Dog whelks are marine snails with either pale yellow, white or grey pointed shells. Often found on the mid-lower shore in cracks and crevices. On more exposed or wave crashed shores, dog whelks develop a larger foot to enable them to stay attached to rocks. On more sheltered shores, dog whelks develop a thicker shell, and a less well developed foot to help protect them from predators.

Topshells

Topshells are marine snails, characterised by a pyramid shaped shell, and are often found on the lower shore as

they are not tolerant to drying out.

Periwinkles

Periwinkles are marine snails, characterised by pointed shells which are black, grey or dark brown in colour. Periwinkles, and other winkles, are found on the upper shore as they have an ‘operculum’ or trap door that enables them to close their shells during low tide to avoid drying out.

Anemones

Found on the mid-lower shore amongst cracks and crevices. Anemones are related to jellyfish, due to the

possession of stinging cell tentacles that they use to catch their prey.

During low tide (pictured), anemones retract their

tentacles and produce mucus which helps prevent water loss.

Hermit crabs

Found on the high-mid shore and in rock pools. Hermit crabs use the empty shells of marine snails to protect them from drying out and from being eaten by predators.

Blue velvet swimming crab

Found on the mid-low shore under boulders and in

rock pools. Blue velvet swimming crabs have dark blue shells and red eyes. The blue velvet swimming crab can be very

aggressive so be careful when trying to handle them.

Shore crab

Found on the mid-low shore under boulders and in rock pools. Shore crabs are usually green in colour with sharp ‘points’ on the front edge of the shell. Just like most rocky shore crabs, shore crabs move very little during low tide to minimise water loss through their leg joints.

Edible crab

Found on the mid-low shore under boulders and in

rock pools. Edible crabs have red-brown or pinkish colour shells

with a ‘pie-crust’ pattern around the edge.

Starfish

Starfish are not tolerant of freshwater or drying out, so must remain on the lower shore and are often found under boulders. Starfish have tube feet which help them stick to rocks so they don’t get washed away in the tide. They can also grow back an arm if eaten by a predator.