Pomatoceros triqueter (Keel worm)


Type of fouling organism: Tubeworm

Tubeworms are polychaete worms from the Phylum Annelida. Each individual tubeworm comprises a slender cylindrical body with distinctive ring-like segments. Some species secrete a tough outer tube made up of chitin to contain their body, while others living in sediment can build a case by fusing surrounding materials with mucous. The tube acts as a support and protects the body from predators. Although these adults are anchored to one spot, in most cases their top end can protrude beyond the tube to access the water column. Tubeworms can be predatory, filter- or deposit-feeders. Tubeworms are resilient animals and as well as being found in fouling communities, many species are found deep in the ocean living around vents tolerating high pressure and high temperatures.

The annelid worm Pomatoceros triqueter appears as a white, smooth, irregularly curved calcareous tube. There is a distinct ridge along the length of the tube, which tapers to a point at the tail end. The tube is usually 3.5 mm wide and up to 25 mm in length. The colour of the tube varies, but is usually bright white to cream. P. triqueter encrusts rocks, stones and shellfish.

Environment and Habitat

- Epibenthic, encrusting available hard substrates including the carapace of some decapods.
- Mainly sublittoral down to a depth of 70 m.
- Feeds on plankton and detritus.
- High intolerance to substratum loss, smothering and decrease in salinity.
- Intermediate intolerance to desiccation, decrease in temperature, abrasion and disturbance.
- Tolerates higher salinities, changes in turbidity and suspended sediments and decreases in wave exposure.


- Reproductive type: Hermaphrodite.
- Reproductive frequency: Annual.
- Development: Planktonic.
- Larval duration: 11 - 30 days.
- Dispersal potential: > 10 km.
- Age at maturity: Ca 4 months.
- Life span: 1 - 4 years (likely 1.5 years in the field).


- Solitary.
- Non-migratory.
- Permanently attached.


- Stock species particularly shellfish, oysters, scallops and mussels.
- Fishnets, cages, pontoons, shellfish trays, tanks, pipes.

Effects and Impacts

- Can reduce the value of shellfish.
- Can increase the weight of bivalves shell, interfering with normal biological function.
- Tubeworms can compete with stock species for space and resource.
- Increases labour and production costs as a result of cleaning and removal of biofouling.

Control/ Strategies and Management

- Onshore Net washing
- Coatings (Copper sulphate, fouling release coatings e.g. silicon)
- Mechanical cleaning of infrastructure (Disk cleaners)
- Air drying nets
- Manual cleaning (scrubbing and/or brushing)
- Low power washing
- High power washing
- Jet washing
- Air drying
- Lowering trays below photic zone during major spatfalls
- Biological Control (Sea urchins and periwinkles)
- Coatings (Copper sulphate, fouling release coatings e.g. silicon)
- Manual Cleaning
- Mechanical Cleaning
- Hot water 55oC for 5 seconds (Stock mortalities of ca 5% with this method)
- Dipping (Freshwater or chemical solution)
- Lowering lines below photic zone during major spatfalls
- Biological control (Sea urchins and periwinkles)
- Coatings (Copper sulphate, spiky coatings, fouling release coatings e.g. silicon)

Principles of Management

C Combat Settlement
P Protect Equipment and Stock
R Remove Biofouling


- Common throughout the north east Atlantic and Mediterranean.


Riley, K. & Ballerstedt, S., 2005. Pomatoceros triqueter. A tubeworm. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 05/02/2007]. Available from: species/Pomatocerostriqueter.htm

Tubeworms: life/tubeworms.html

Janet Moore (2001) An Introduction to the Invertebrates. Cambridge University Press

Hayward P, Nelson-Smith T & Shields C (1996) Seashore of Britain and Northern Europe. HarperCollins Pubs.

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