Biodiversity & Conservation

Laminaria digitata and piddocks on sublittoral fringe soft rock



Image David George - View across shore showing extensive kelp beds on chalk. Image width ca 4 m.
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Distribution map

IR.MIR.KR.Ldig.Pid recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats
  • UK_BAP

Marine natural heritage importance

Listed under EC Habitats Directive
UK Biodiversity Action Plan
National importance Scarce
Habitat Directive feature (Annex 1) Reefs
Large shallow inlets and bays

Biotope importance

Kelp beds provide refuge for nursery areas for a wide range of species and it is likely that juvenile forms of all the animals that are present as adults in the kelp bed make use of the habitat as a nursery area. Other species may only make use of the habitat during parts of their lifecycles.

  • Laminaria digitata plants can reduce current flow and ameliorate wave exposure, allowing more delicate organisms to survive in the shallow sublittoral. Shading by the canopy allows shade tolerant algae, especially Rhodophyceae to extend into the upper infralittoral.
  • Kelp plants themselves usually become the habitat for other marine species providing attachment sites for a wide range of other seaweeds and sessile animals. Kelp beds also contain a series of stratified habitats supporting an extremely diverse fauna (see Habitat complexity).
  • Kelp beds are important primary producers of organic carbon for surrounding communities (see Productivity) (Birkett et al. 1998b).
  • Empty piddock burrows provide refugia for species especially anemones, small crabs and worms.

  • Exploitation

    Kelp species around the world have been exploited over the years as a source of chemicals for industry. Kelp cast up on the shore has long been collected for use as an agricultural fertilizer. More recently Laminaria digitata is commercially harvested in Brittany for alginate production and in Ireland and France for sea-vegetable production.

    Additional information icon Additional information

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    This review can be cited as follows:

    Hill, J.M. 2008. Laminaria digitata and piddocks on sublittoral fringe soft rock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 30/11/2015]. Available from: <>