The lugworm, arenicola marina, also goes by the names of both rock worm and blow lug. They can measure up to 7.8 inches (20 centimeters) in length. This worm comes in a variety of colors such as pink, green, brown, red or black. Their cylindrical bodies are made up of 2 distinct regions. The first (known as the thoracic region) bear bristles (called ‘chaetae’), while the last 13 segments of this region have bushy gills. The abdominal region (which consists of the tail end of the creature) is thinner than the thoracic region and lacks both bristles and gills.
The lugworm can be found in western Europe, Iceland, Norway, Siberia, Greenland, all the way to the coasts of the western Atlantic. They are especially common around all the coasts of Britain and Ireland. They will inhabit middle to lower shores in both sand and muddy sand as well as in sheltered estuarine sediments. They will live in J-shaped burrows located anywhere from 7.8 to 15.7 inches (20 to 40 centimeters) below the surface.
The diet of a lugworm consists of organic material such as micro-organisms and detriment found in the sediment. The detriment is ingested while the creature is in its burrow, leaving a depression on the sand’s surface. After all of the useful organic content has been taken from the sediment, it is expelled (which produces their characteristic worm cast). They have an organ of equilibrium (called the statocyst) which allows this creature to both always burrow head down and orient themselves for feeding. Even though the lugworm is generally safe in its burrows, it is still preyed upon by both flatfishes as well as birds.
Spawning time for the lugworm takes place from October to November. Males will release inactive sperm, which will settle into puddles on the sediment surface. The tide will disperse the sperm (as well as make them active) and the respiratory current will draw them to the female’s burrow (where she lays her eggs). The resulting larvae will initially develop in the burrow and then crawl their way to the surface to be dispersed by the currents. They will settle on areas of shingle or sand and will make their home inside mucus tubes attached to the sediment. These tubes will detach after a few months, and the young ones will drift in the water for a time before burrowing within the sediment. If the little ones can survive long enough, then they can live to be up to 6 years old.
The lugworm is not threatened and is in fact both common and widespread. They are a very important food source for many wading shore birds and are often used as bait in angling. Hopefully, the lugworm can continue its peaceful coexistence with humans and avoid ever having to face the possibility of extinction. After all, such a unique creature deserves to live and prosper far into the future.
“Lugworms, Arenicola Marina” 8 January 2012
“Lugworm (Arenicola Marina)” 8 January 2012