Biodiversity & Conservation

Ascophyllum nodosum ecad mackaii beds on extremely sheltered mid eulittoral mixed substrata



Image Sue Scott - A dense mat of Ascophyllum nodosum mackaii. Image width ca 40 cm.
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Distribution map

LR.SLR.FX.AscX.mac recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats
  • UK_BAP

Text page icon Habitat description

Map icon Distribution of biotope in Britain and Ireland The distribution of Ascophyllum nodosum ecad mackaii is limited to Scottish sealochs, Strangford Lough in Northern Ireland and a few sites in the Irish Republic.
National importance Scarce

Text page icon Description of biotope

For a full description of this biotope including characterizing species, distribution, survey information and references visit JNCC

Extremely sheltered mid shore mixed substrata, usually subject to variable salinity due to freshwater runoff, may support beds of the free-living Ascophyllum nodosum ecad mackaii. Cobbles and other hard substrata are often characterized by the normal form of Ascophyllum nodosum and other fucoids such as Fucus serratus and Fucus vesiculosus. The loose mats of A. nodosum ecad mackaii provide a cryptic and humid habitat for mobile species such as gammarids, the shore crab Carcinus maenas, littorinid molluscs (especially Littorina littorea) and eels Anguilla anguilla. Semibalanus balanoides and Mytilus edulis are commonly attached to pebbles and cobbles on the sediment, while the infauna may contain Arenicola marina, Lanice conchilega and other polychaetes. (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Additional information icon Additional information

This review can be cited as follows:

Hill, J.M. 2001. Ascophyllum nodosum ecad mackaii beds on extremely sheltered mid eulittoral mixed substrata. 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: <>