Beautiful tube dwelling worms

Crucigera species

'Ugly' earthworms and nasty parasites. That is probably your first thought, when I mention worms. But  worms are a vital source of food in the sea and can be very beautiful. So far I have not described one single worm in my blog. Shame on me!

In this post I will show and describe a few beautiful and interesting worms, like calcareous tubeworms and feather-duster worms. The worms pictured in this post inhabit the jetty of Rock Bay, Vancouver Island, Canada (or otherwise mentioned), which I described in the previous post

Crucigera species

The photo's above and the one below show a Crucigera species. In this region there are two Crucigera species: C. zygophora, the yoke-bearer calcareous tubeworm, and C. irregularis. Unfortunately the distinctive differences between these two species are not visible on the photo's (and other photo's I took). Length up to 4.5 cm.

Crucigera species

Worms are difficult to study. To begin with: what we call worms, can be animals of very different phyla. There are 13 phyla that include worm-like animals. The worms in this post all belong to the Annelida, in particular to the class Polychaeta, the bristle worms.

All Polychaetae are segmented animals. They are called bristle worms because of the many bristles on their parapodia: fleshy protrusions on each segment often used for movement. Hence their name: in Latin poly means many and chaetae means bristle = many bristles. 

Serpula columbiana

This is Serpula columbiana, the red-trumpet calcareous tubeworm. It forms, just as Crucigera, a tube made of calcium carbonate, mucus and carbohydrates. Length up to 6.5 cm.

Serpula columbiana

Serpula columbiana (Tyee Beach)

Both species of calacareous tubeworms have a trumpet like trap door, the operculum, to seal of the entrance of the tube against predators and if need be against dehydration. This trumpet like shape is easy to see in the photo above.

Serpula columbiana (Tyee Beach)

All the worms in this post have a crown of tentacles. These feather like tentacles, called radioles, are arranged in two spiralled lobes and are for feeding and respiration.

Serpula columbiana (Tyee Beach)

Close-up. The lateral branches of the radioles are called pinnules.

Serpula columbiana (Tyee Beach)

A white specimen emerging from its calcareous tube.

Schizobranchia insignis

Palm tree beach? No, feather-duster worms heaven. This is the split-branch feather-duster, Schizobranchia insignis. The tubes of feather-duster worms consist of a mucus and sediment combination.

A lot of the photo's in this post are actually 90º or 180º rotated: in real life these worms were hanging upside down or tilted downwards. As I have a very strong preference to look at things from a 'normal' perspective, as most humans do, I rotated the photo's.

Schizobranchia insignis

Beautiful crown of feathers. You can discern the dichotomously split feathers. The little blacks dots on the feathers are unpaired compound eyes.

Schizobranchia insignis

Schizobranchia insignis

Some specimens have 'highlighted' feathers, like the hair fashion in the eighties.

Schizobranchia insignis

The jetty of Rock Bay is riddled with these beautiful worms! To quote the excellent book 'Marine Life of the Pacific Northwest' (Lamb & Hanby, 2005) about a 'nephew', the Vancouver feather-duster worm (see later): '...and records from the early 1920s estimated that large groves contained as many as 375,000 to 500,000 individuals.' Length up to 16 cm.

Schizobranchia insignis

This specimen shows clearly that it is a worm. It was hanging from its tube and was clearly wounded.

Schizobranchia insignis?

I found quite a lot of these smaller worms and I think they are young specimens of S. insignis. Again the eyes are clearly visible.

For these tube dwelling worms hard, rocky substrates are the preferred sites for attachment. The jetty of Rock Bay is made of styrofoam, the cream-white substrate on the photo.

Eudistylia vancouveri

This is probably the Vancouver feather-duster, Eudistylia vancouveri. Its feathers are not branched and this is the common colour variety. However, a 100% identification is only possible by microscopic examination.

Demonax medius

Demonax medius, the parasol feather-duster. Distinguishing feature: the two lobes of this feather-duster jointly expand to form a symmetrical, virtually unbroken circle (Lamb & Hanby, 2005). Length up to 10 cm.

Myxicola infundibulum

Myxicola infundibulum, the slime-tube feather-duster, lives in sand or mud (photo above). Length up to 20 cm (Carlton, 2007). Distinguishing feature is the membrane connecting the radioles together over most of their length. Their tube is just mucus: no sediment, no calcium carbonate.

The worms readily retreat in their slime tubes when disturbed. The species is of European origin, but current investigations suggest that these local species are actually different from their European counterparts (Lamb & Hanby, 2005). I have seen Myxicola infundibulum in Brittany, France, where it is quite common.

Myxicola aesthetica

Myxicola aesthetica*, the Petite slime-tube feather-duster lives communally in rock crevices (photo above and below) or other hard substrate like the styrofoam of the jetty.

Myxicola aesthetica (tubes)

Sabellinae species

I found it far from easy to distinguish worm species. In a lot of cases you are forced to collect specimens: the distinguishing features are sometimes microscopic small and can not be seen on a photo, even when the worm is fully expanded. This worm (top and bottom) belongs to the subfamily Sabellinae.

Sabellinae species

There are about 10,000 polychaete species described. Because of their often hidden, nocturnal and obscure way of living, as a marine biologist you can spend your lifetime discovering and describing new species!

* Thanks to Marco Faasse who told me this was not Myxicola infundibulum, but M. aesthetica (Feb. 2025).

Seascapes and Rock Bay's jetty

I skip a post about a few species of fish of Vancouver Island for now, as I want to show you some very beautiful worms (yes worms!). But while writing and selecting photo's I realized I haven't shown and described the landscape. And there is one man made structure I need to show you before the post about worms, because this structure creates the environment in which these animals thrive. It is also a justification to show some more 'seascapes'.

I took the first photo's of this post on the ferry from Tsawwassen (mainland) to Schwartz Bay (near Victoria, Vancouver Island). The weather forecast said sunny. It wasn't sunny at all, but I enjoyed the misty and grey weather. To see tiny islands popping up in the mist, like Atlantis the other way round.

If you don't know where to find Vancouver Island have a look at these Google Earth-maps.

You can see how narrow the Johnstone Strait is and it doesn't take a lot of imagination to understand how fierce the tidal current can be.

Both our journeys to and from Vancouver Island we saw a sharp-edged barrier between muddy and clear(er) water. This was at a distance of a few hundred meters from islands in front of the main island. I have no idea what caused it, but I was glad that at my dives the water wasn't as drabby as the dominant stream!

It was difficult to find a nice spot to stay for the first night in our camper van. All spots had a sign: no camping from dusk to dawn. Very different from Newfoundland. At 8.00 PM we found - at last - a nice place. See the lovely view. But after a while we were ordered to get out. It appeared to be a first nations reserve...

The last week we stayed at Rock Bay and this was our view.

Rock Bay itself: a small natural bay, here at high tide. There is a boat ramp and a jetty. The jetty is made (mostly) of wood and is floating on huge blocks of styrofoam! It is simple but does the job.

At extreme low tide.

A Google Earth-map of Rock Bay. You can see the jetty and the floating tree trunks, which protect the bay; my dive boundary. In the olden days it was a small village with a hospital and 1.500 inhabitants, owned by a tree logging firm. Now it is a camp site with no water or electricity but with very nice and hospitable people. And still owned by a tree logging firm. As Wayne told me: Rock Bay is for sale with a huge amount of woodland for just 1,2 million Can $. But for the same price you can buy the island at the other side of the strait. An island of your own.... Unimaginable in the Netherlands.

The boardwalk is a mess, but I like it: it's very photogenic.

Still existing: wooden base of the former railway.

I already mentioned Wayne. He and Linda were our very hospitable and friendly neighbors.

They had their own boat and frequently went out to catch a fish for dinner. They took us on a fishing trip and tried to teach us how to fish. We were no good but enjoyed the trip.

Linda preparing fresh salmon.

Wayne told me the logging firm is going to replace the jetty. They were glad but I am not. Why? That will be revealed in my next post.

Meet the fascinating spotted ratfish

During one of my dives at Rock Bay, Vancouver Island, at a depth of 12 m two strange looking fish swam towards me. I knew the species only from drawings and a few photo's: dragonfish! I was astonished, because I thought this was a deep sea species that hunts in the dark. But now here, in this shallow water and at broad daylight?

It were two spotted ratfish, Hydrolagus colliei (NL: gestippelde draakvis). I don't think ratfish is an appropriate name. I prefer the Dutch (NL) name: draakvis, i.e. dragonfish. Because it looks like something mythical; an animal of long forgotten times. It belongs to the family of the Chimaeridae. Now we're talking, because that name refers to a mythical beast, the Chimaera.

The first time they swam towards me, they were not really interested, kept a distance of about 4 m and swam away. I know it is no use swimming after fish. They get frightened and just get away. After 20 minutes I saw them again at greater distance. I thought: let's be patient, maybe they are curious and will swim to me. In the back of my head I also thought of danger. A poisonous spine? How I knew I don't know. Maybe I read it years ago, maybe it was intuitive.

Bingo: after a while one of the two glided towards me. Observing me with its strange eye and keeping low, a few decimeters from the bottom, it came closer and closer. I was enthralled!

At that dive I used a 24 mm wide-angle lens and dome port. For close by shots of the head she (as it later appeared to be) had to swim within 'hands reaching'. So I was thinking: closer, come closer. She did! She came as close as 30 cm and must have seen herself reflected in the dome port. She swam away, turned and made it possible for me to make photo's of her profile from head to tail. As Canadians often say: awesome.

And the spine? Have a look at the first photo of this post and you see its first dorsal fin (= fin on its back) with the big spine going skywards at the last moment. That does not mean she was going to use it offensive. I think it is more like making an impression, showing off as a lot of fish do: here I am and don't mess with me, otherwise....

Afterwards I read in '151 Dives', an excellent book/diving guide by Betty Pratt-Johnson (2007): 'Avoid the spine. Once a ratfish bit my leg on a night dive. The only attack I have heard of yet, but beware.' Moen & Svensen (2004) about its Atlantic counterpart Chimaera monstrosa, also the ratfish or rabbitfish (NL: draakvis): '..has a stout spine connected to a poison gland that produces a deadly poison.' Deadly for humans?


© Wheeler: Fishes of the World

What's in a name? There are a lot of common names for members of the Chimaeridae: ratfish, rabbitfish, ghost shark, elephant fish. Hydrolagus means water hare. Compare that with rabbitfish. But what about rat, rabbit, hare or elephant: they don't like like it. Wheeler (1975) shines a light: 'Its name rabbitfish refers to its rabbit-like incisor teeth, while ratfish is in reference to its very long tail.' I keep on nagging about names: the tail of the spotted ratfish does not look like a rat's tail at all, contrary to its Atlantic nephew. Compare the drawing overhead of Chimaera monstrosa (Wheeler, 1975) with my photo's of Hydrolagus colliei.


Apart from its exotic appearance, for me there is one thing that sticked out: the 'panels' forming the head. If you take a look at the head you see a kind of panels that seem to be riveted together. Just like the plating of a ship is nailed together. If I am not mistaken, those formerly loose parts, nowadays one piece, are one of the characteristics of fish of prehistoric times.
Paleontologists trace this family back to the Devonian era, back 345 millions years. They belong with the sharks and rays to the cartilaginous fishes.

Nowadays there are worldwide approximately 35 species (Debelius, 1998). Most inhabit deep seas. That's why I thought at first sight: what are you doing in these shallow waters? But shallow waters are not uncommon for Hydrolagus, as for Chimaera monstrosa: Wheeler (1986): '...it seems that the ratfish migrates in unisexual shoals, large females being found in shallower waters in spring and summer... .'
And Betty Pratt-Johnson (2007) refers quite frequent to this ratfish, albeit several times while night diving: 'The eyes of ratfish glow like sapphires.'

She was about 75 cm long. The maximum recorded size is 97 cm. Why I think it is female (at least the one that came close)? Lamb & Edgell (1975): 'Males have an evertable projection on the head, that sits in a pit and is used during mating to grasp a female. Only males have claspers (sex organs).' I don't see a pit on the head of 'my' ratfish and no claspers near its pelvic fins.

The following day I saw them again; the same couple I expect. They showed no interest at all in that big man in black with all its preposterous diving gear.