Biodiversity & Conservation

Ascophyllum nodosum, sponges and ascidians on tide-swept mid eulittoral rock


<i>%Ascophyllum nodosum%</i>, sponges and ascidians on tide-swept mid eulittoral rock
Distribution map

LR.HLR.FT.AscT recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • UK_BAP

Marine natural heritage importance

Listed under UK Biodiversity Action Plan
National importance Not available
Habitat Directive feature (Annex 1) Reefs
Large shallow inlets and bays

Biotope importance

The lush canopy associated with this biotope may provide many motile invertebrates with protection from insolation and desiccation at low tide. In addition to the flat periwinkle, Littorina obtusata, other invertebrates may lay their eggs within the canopy layer and it may act as a nursery ground for shallow water fish.


Of the key, characterizing and important species, it is only the algal species that are exploited regularly. Details of their exploitation and uses are summarized below.
  • Ascophyllum nodosum is harvested in Ireland and Scotland for use in alginates, fertilisers and for the manufacture of seaweed meal for animal and human consumption. The species is also harvested in Europe, Canada and the north-west Atlantic. Poor resource management and over-exploitation have led to severely depleted populations in many regions.
  • Fucus serratus is collected, dried and used as a soil additive. Various fucalean algae are used in the production of alginates which, in turn, are used widely in the pharmaceutical and cosmetics industries.
  • Fucus vesiculosus is also collected although only a small amount of the available resource is reported to be used and is hand cut or collected as drift (Morrissey et al., 2001). Morrissey et al. (2001) listed many uses for Fucus vesiculosus including fertilizer, bodycare products, such as shower gels and body creams, and health supplements (kelp tablets). The boiled broth can also be used as a health drink (Guiry & Blunden, 1991).
  • Chondrus crispus is harvested commercially in Ireland, Spain, France, Portugal and North America for the extraction of carrageenan (Guiry & Blunden, 1991). In Ireland, harvesting has generally remained sustainable through pickers developing an intuitive feel for the annual cycle of local stocks and certain practices which involve pulling only the bushy top half of the frond off leaving the base and holdfast behind (Morrissey et al., 2001). The gelling and thickening properties of carrageenan are used widely in the food, pharmaceutical and cosmetics industries (see MarLIN review).
Harvesting Ascophyllum nodosum, thereby removing the dominant and characterizing canopy species, could be catastrophic for the biotope if the whole plant was removed (see 'Extraction of key and important characterizing species' in Sensitivity section).

Additional information icon Additional information

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This review can be cited as follows:

Marshall, C.E. 2005. Ascophyllum nodosum, sponges and ascidians on tide-swept mid eulittoral rock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/11/2015]. Available from: <>