Sherkin Island Marine Station

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Ireland's Seashore

Photography by Paul Kay & Terry Farnell

© Sherkin Island Marine Station

Scorpion Spider Crab
Inachus dorsettensis
Portán faoilinne scairpe

There are several species of spider crab to be found on the shore. All get their name from their long-legged, spidery appearance, although, unlike spiders, they have five pairs of walking legs, including the pincers. All spider crabs have a roughly triangular body. In the Scorpion Spider Crab, this may be heavily camouflaged with sponges and seaweed, which it has picked off the rock and stuck to its shell. It has a curious habit of holding its pincers poised close to its body.


Blue-rayed Limpet
Helcion pellucidum
Bairneach mín

Often found attached to the fronds of kelp seaweeds, this sea snailís body is covered by a single uncoiled shell. When young, the shell is smooth and orange-brown in colour with broken electric blue lines running down its length. With age, its colour fades to a dull brown, with darker banding and grey lines. The Blue-rayed Limpet normally feeds on kelps, but also feeds on encrusting animals or plants. Oval scars on the fronds and stems of kelps are "home bases" to which the limpet returns after feeding.


Dahlia Anemone
Urticina felina
Bundún leice dáilia

This is the largest anemone to be found on the shore. It gets its name from its stunning, flower-like appearance. The short, stubby tentacles and mouth disc are patterned with bands of colour ranging from blues and greens to pinks and reds. A strong, sucker-like base ensures firm attachment to the rock, even in the most wave-swept sites. The column is often covered with warts to which bits of shell and gravel stick, providing a good disguise when the tentacles are drawn inside.


Mermaid's Purse
Scyliorhinus canicula
Sparán na caillí mairbhe

The Mermaidís Purse is the egg case laid by the dogfish in deeper waters. It has long, twisted tendrils on each corner which are used to attach the egg case to seaweed and other floating structures. It is light brown and almost see-through. The egg case is usually only seen when it is washed up on the shore, and then it is often dry and hard. It is normally empty, as the young fish will have hatched by the time the case is washed ashore.


Breadcrumb Sponge 
Halichondria panicea
Spúinse grabhrógach

One of the commonest sponges to be found on the seashore, the Breadcrumb Sponge, forms encrusting patches on rocks and on the stems of kelp. Varying in colour from yellow to pale green, it has a distinctive appearance. The smooth surface is dotted with volcano-shaped openings which are called exhalent openings. The inhalent openings are too small to see. When handled, the crumbly-textured sponge breaks easily and gives out a strong bread-like smell, hence its common name.


Velvet Swimming Crab
Necora puber

This crab gets its name from the velvet feel of its shell, and its paddle-like back legs, which are used for swimming. Its bright, red eyes and aggressive nature have earned it the nickname "red-eyed devil". The hairy carapace is wider at the front than at the back. The front edge is also deeply toothed, giving it a saw-like appearance. Usually dark grey to brown in colour, features to look out for are the dark blue-black lines on its legs and bright blue joints.

© Sherkin Island Marine Station 2006