Type of fouling organism: Bivalve

Bivalves are molluscs and include species of oyster, scallop, mussel, cockle and clam. All are aquatic and most are marine. Their body is laterally compressed between two halves of a hinged shell. Many bivalves are sedentary with a foot that secretes a number of byssus threads that enables them to attach to the substratum. Feeding is by way of two main ciliary tracts located on enlarged gill surfaces within the mantle which is contained in the shell. Hair-like structures (cilia) produce water currents and trap food particles beating them towards labial palps allowing small particles to be conveyed to the mouth.

The shell is rectangular but can also be irregular, reaching sizes up to 40 mm. Usually one end is rounded and the other truncated or cut shorter. Two ridges run towards the truncated end on both valves, which are dull white to yellow brown in colour.

Environment and Habitat

- Subtidal to depths of 50 m.
- Attaches by thread-like hairs in holes and crevices or to algal holdfasts.
- Often bores into soft rock and shells.

Reproduction

- Reproductive type: Separate sexes.
- Reproductive frequency: Unknown.
- Development of larvae: Planktonic.
- Larval duration: Insufficient information.
- Dispersal potential:> 10 km.
- Age at maturity: Insufficient information.
- Life span: Insufficient information.

Communities

- Solitary.

Equipment

- Found on other biofouling organisms.
- Stock species particularly shellfish.
- Fishnets, cages, pontoons, shellfish trays, tanks, pipes.

Effects and Impacts

- Problematic for stock species as can compete for space and resources.
- Increases the weight of equipment and cause damage to infrastructure through burrowing.
- Increases labour and production costs as a result of cleaning and removal of biofouling.

Control/ Strategies and Management

Nets
- Onshore Net washing
- Coatings (Copper sulphate, fouling release coatings e.g. silicon)
- Mechanical cleaning of infrastructure (Disk cleaners)
- Air drying nets
Trays
- 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)
Shellfish
- 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

Distribution

- From Arctic waters to at least the Mediterranean and north west Africa.

References

Carter, M.C., 2003. Hiatella arctica. Wrinkled rock borer. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/05/2007]. Available from:

Sejr, M.K. Sand, M.K. Jensen T. Peterson, J.K. Christensen, P.B. Rysgaard, S. (2002) Growth and production of Hiatella arctica (Bivalvia) in a high-Arctic fjord (Young Sound, Northeast Greenland). Marine Ecology Press series. Vol. 244: 163-169.

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.