Worms

The shores of Ireland are home to a wide variety of worms, some of which burrow beneath the sand or build large reef-like colonies, while others create small chalky dwellings so that they can survive on the exposed surface of rocks.

• Lugworms (Arenicola marina) are found buried in “U”-shaped burrows beneath the surface of sandy beaches below the low water mark. These burrows can be detected by the small cone-shaped depression in the sand at one end and a swirl of extruded sand at the other. Lug worm feed by ingesting sand, digesting any organic matter contained in it and then passing the waste sand up to the surface. They are frequently dug by anglers for use as bait. In shape, they look very similar to the common earthworm, apart from the prominent bristles near the mouth and the red gills further back.
   
• Ragworms (Hediste diversicolor) are the predators of the worm world and are equipped with a very powerful pair of jaws that can give bait diggers a sharp bite. Unlike lugworm, ragworm are fast moving and can even swim in open water. They have a prominent blood vessel that can be clearly seen running down their backs and short stiff paddles on either side to assist with swimming. They feed on other worms, shrimps and any dead animals they can find.

Beach at Wicklow Head

This headland marks the most easterly point of County Wicklow.The seabed offshore, which is swept by strong tidal currents, has an unusual series of reefs formed by honeycomb worms. (Richard Nairn)

copyright R. Nairn

Beach at Wicklow Head
copyright R. Nairn

Beach at Wicklow Head

This headland marks the most easterly point of County Wicklow.The seabed offshore, which is swept by strong tidal currents, has an unusual series of reefs formed by honeycomb worms. (Richard Nairn)

copyright R. Nairn

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• Honeycomb Worms (Sabellaria alveolata) live in large colonies made of sand tubes glued together with saliva to form a honeycomb structure like a beehive. These colonies can be found on the lower shore and, at long distance, resemble rocks. The worms themselves, which are only about 4cm long, feed on tiny organic particles in the water with specialised tentacles that also form a plug to their burrows when drawn in.

• Sand Mason Worms (Lanice conchilega) live in short sand tubes with ragged ends resembling tiny bushes at low water on sandy shores. Like the Honeycomb Worms, they feed on drifting organic particles which they capture with their tentacles, drag into their burrows and digest.

• The Peacock Worm (Sabella pavonina) lives in a thin tube made of mud granules cemented together with mucous. Its head is surrounded by a delicate “flower” of coloured gills that branch out into the water to capture organic particles, which are then passed back to the mouth. Peacock Worms tend to live in groups on muddy sea bottoms and will retract rapidly back into their tubes when disturbed.

• Keel Worms (Pomatoceros triqueter) and their smaller cousins the Coiled Tube Worms (Spirorbis sp.) excrete a while tube of calcium carbonate to protect them from danger. The tubes of Keel Worms are larger than those of Coiled Tube Worms and have a pronounced ridge or “keel” along their back, while the tubes of Spirorbis can be so small as to resemble tiny white commas. Both these worms feed and breath by means of gills around their heads. They are found on any hard surface, or even on seaweed fronds, from the middle shore downwards.