A few worms
Worms are tricky – they tunnel, move and there are plenty of them. Many require a good view of the head, which commonly isn’t on view and many can’t be ID’d in the field.
Some worms’ ecologies can help with ID and others which make tubes leave a slightly clearer and more sedentary feature which can help with ID-ing as well.
You will see what they or their signs/tubes look like and learn of their ecology to help with ID.
You will then be tested.
The species in focus are:
honeycomb worm/llyngyren ddiliau (Sabellaria alveolata)
sand mason/saer y tywod (Lanice conchilega)
spirorbid worm/tiwblyngyren dorchog (e.g. Spirorbis spirorbis)
keel worm/tiwblyngyren drumiog (Spirobranchus sp.)
greenleaf worm (Eulalia viridis)
lugworms (Arenicolidae worms)
Introducing some tube-living worms
honeycomb worm/llyngyren ddiliau (Sabellaria alveolata) 
©Lee Anthony Bell
- a worm which creates a solid, if fragile, tube from sand grains, within which it lives, usually attached to other tubes created by fellow worms in a small or large group
- when conditions are right, the worms attached together can be so numerous they create what’s called a biogenic reef (a relatively sturdy structure which provides attachment, crevices, pools etc for many other species to use to live)
- this worm can be found in small patches within man made structures to large established reef-formations
- you may find the tubes in a worn state, so to establish the worm is resident, look for a small “canopy” over the entrance (the worms compete for food with their neighbours and so need to continue to add to their burrows if they’re alive)
sand mason/saer y tywod (Lanice conchilega)
©North Wales Wildlife Trust
- a terebellid worm which decorates it’s elastic-type outer coating in sand grains
- growing a tube up to 45cm in length
- it lives upright in the sand with the top part of its tube showing above the sediment surface
- has a “crown” of glued-together sand grains, which is sometimes not present (washed away, perhaps), but which is thought to help eddy the water and catch food
- can often be seen at low tide in groups in sand, but also in small patches of sediment between rocks as well.
spirorbis worm/tiwblyngyren dorchog (Spirorbis sp.)
©North Wales Wildlife Trust
- worms which make white, attached calcified tubes within which they live
- the tubes are circular in route and small 3-4mm in diameter
- found on hard substrate, but also commonly seen on algae
- several difficult to ID species, so best recorded as a group of worms.
keel worms/tiwblyngyren drumiog (Spirobranchus sp.)
©North Wales Wildlife Trust
- more worms which make white (sometimes pink), attached calcified tubes within which they live
- the tubes are not in an organised shape
- each tube has at least one raised “keel” central on the surface along its length
- the tubes can be seen attached to rocks, shells and other hard surfaces.
Now you’ve seen some of our most commonly seen worms which use tubes (or ones which can be identified fairly readily at to a species grouping), note there are plenty more out there. So, keep an eye out and prepare to collect as much information on what you see when you do.
Of the worms chosen there are some similarities with other species, but some are less likely seen due to where they’re found etc. Also, the spirorbid worms are a grouping and the need to ID to species is left to the interests of the surveyor. So, the focus here is on one of these worms which in the intertidal region is likely to be one of only two species (although this isn’t entirely clear cut). Both make white, calcareous tubes within which they live, but the keels can differ.
- the tube of Spirobranchus lamarkii has two smaller ridges either side of the single central ridge, S. triqueter does not have this
- Spirobranchus triqueter can have an extension of this central ridge over the opening
- Spirobranchus lamarkii is more common in the lower intertidal region than S. triqueter.
greenleaf worm (Eulalia viridis)
- distinctive bright green coloured polychaete worm
- long, slim worm up to 15cm long
- head, if seen, has four short forward-pointing antennae plus an extra one, two large eyes and 4 pairs of longer tentacle-like hairs pointing backwards
lives in crevices, around barnacles and on mussels - it lays eggs on shore which may be the green gelatinous masses seen attached with threads in shallow pools and hanging from algae.
lugworms/abwydyn (Arenicolidae worms)
©North Wales Wildlife Trust
- you’re unlikely to see these worms themselves, unless you dig for them as they live in a u-shaped burrow in the sand
- they leave casts (poo/faeces) in squiggles/circles on sediment surfaces at one end of the burrow and often you can see an indentation close by indicating the entrance
- the worm cast can be found across the mid to low-shore and beyond.
Alternative factoids
The plethora of worms in our marine systems means there’s plenty more to learn. Here are some fascinating facts about worms.
There is a ribbon worm species which is a contender for being the longest animal on earth (fighting the lion’s mane jelly with its long, fine tentacles and the blue whale) – it’s called the bootlace worm and can be found intertidally in the UK.
Different species of worm feed in different ways, some filter using fanlike tentacles, others take sediment into burrows and many more hunt their prey across the shore.
Male lugworms are known to release sperm into shallow puddles at low tide after a cold snap in Oct/Nov each year and when the tide comes back in the sperm gets washed into the female burrows.
Some worm live inside shells occupied by hermit crabs. They are tolerated they steal bits of food while the crab dines.
Some common English names for worm species in the UK are Eyelash worm, peacock worm, football jersey worm and candy-striped worm – highlighting just how colourful these worms can be, although often only when underwater.
After an in-depth course from staff from Amgueddfa Cymru we have further resources to share with those keen to introduce themselves further to our intertidal worm species. This is additional information and will not be part of the quiz.
worm-cards-all
The next section is the quiz. Click to begin the quiz, the questions will appear below. If you get any one question wrong within each quiz page, the you will be marked as wrong for the whole page. Answers will appear one you’ve finished each question.
You will be tested on what you’ve learnt so far using the reading and video info. Don’t worry too much, as once you’ve been out on the shore, the ID features you’ve learnt about will make more sense and after a couple of visits you should feel more confident about your ID.
Good luck!