Facts about this animal
The Spiral Tube-worm - sometimes listed under Spirographis spallanzanii - is a rather large sessile annelid, i.e. segmented, worm which lives in a tube of parchment-like consistency made of mucus and mud or other small particles.
The tube is 30-60 cm long, 10-25 mm wide, and lacks a seal. The 9-40 cm long body has 200 to more than 300 segments and is not fixed to the tube. It is subdivided into a head, a thorax and an abdomen, the last being longest. Two appendages to the head carry a crown of feathered feeding tentacles, of which only one is spiralled with a diameter of 10-15 cm.
The about 300 tentacles are banded in white, yellow, brown and violet and also work as gills. On the thorax, with no more than 12 segments, the parapodia, paired lateral projections of the skin, have straight bristles dorsally and hooked bristles ventrally. On the abdomen bristles are the opposite way. Faeces are transported from the anus at the end of the tube along a ciliated groove on the ventral side of the abdomen and on the dorsal side of the thorax to be expelled at the tube’s opening.
The Spiral Tube-worm often exposes itself to strong currents and feeds on tiny organic particulate matter as well as on microorganisms which are filtered out the water by means of the crown of tentacles. The particles are covered with mucus and transported according their size on three different ciliary grooves along the tentacles. Large ones are expelled by the palps, medium sized ones are used as construction material and stockpiled in pouches next to the lower lip, and the small ones are eaten. Although solitary, several individuals are often clumped. In case of danger the worm retreats its crown of tentacles into its tube with blinding quickness. Other epibiontic organisms like hydrae, ascidians and algae will often settle on the tube. One of the known enemies is the Gilt-head Bream.
The sexes are separate and spawn at the same time. Eggs and sperm cells are broadcast into the water column and fertilization is external. Females produce more than 50,000 eggs if they are longer than 30 cm. In Australia, spawning occurs during the winter months, coinciding with falling water temperatures. The hatched larva is planctonic and is called trochopora. The larva is oval and moves by means of cilia. It settles after about 2 weeks and metamorphoses after 10 more days. Maturity is obtained at 5 cm in Australia and at 15 cm in Italy.
In the Mediterranean Sea the Spiral Tube-worm is used as bait to catch breams what puts wild populations under pressure. Regulation is needed. On the other hand, in Australia where the species is introduced, it competes with other filterers and can affect cultures of mussels and oysters as well as native ecosystems in natural habitats.
Did you know?
that the Spiral Tube-worm competes for space and food with other filterers and, thus, can affect cultures of mussels and oysters? that off Florida another tube-worm, Phragmatopoma lapidosa, exists in such quantities that it built up a reef of 320 km length?
|Name (Scientific)||Sabella spallanzanii|
|Name (English)||Spiral Tube-worm|
|Name (French)||Spirographe, Ver d’anémone, Ver à panache de roche|
|Name (Spanish)||Plumero de mar|
|Local names||Italian: Verme fiocco, Ombrelle di mare, Spirografo|
|CITES Status||Not listed|
|CMS Status||Not listed|
Photo Copyright by
Rudloff Klaus - Berlin Zoo
|Range||Native to the Mediterranean Sea and European coast of Atlantic Ocean northward to the Channel, unintentionally introduced to the waters off Australia and Brazil.|
|Habitat||At surf-protected places like harbours on rocky but also on sandy or muddy bottoms as well as hard artificial surfaces or living bivalves like mussels or oysters from the surface down to 40 m deep. Water must be rich in organic matter and plankton.|
|Wild population||Sometimes at densities of more than 100 individuals per square meter but regionally threatened by exploitation.|
|Zoo population||8 reported to ISIS (2008)|
In the Zoo
Find this animal on ZooLex
Photo Copyright by
Rudloff Klaus - Berlin Zoo
Why do zoos keep this animal
The Spiral Tube-worm has a high potential to clean seawater form organic pollution which can be helpful where such contamination is caused by other tank mates. Additionally, it is used in education to emphasize on one hand its usage as bait, from which it suffers in the Mediterranean Sea, and on the other hand its affect on marine ecosystems and cultures of mussels and oysters in Australia.