Biodiversity & Conservation

Halidrys siliquosa and mixed kelps on tide-swept infralittoral rock with coarse sediment.



Image Rohan Holt - Halidrys on flat pebbles and gravel. Image width ca 1 m.
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Distribution map

IR.MIR.SedK.HalXK recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

Text page icon Habitat description

Map icon Distribution of biotope in Britain and Ireland Recorded from tide-swept but generally wave sheltered habitats of Shetland and Orkney, north east England, the English Channel, the south west, Cardigan Bay and the Sarnau, western Ireland and western Scotland.
National importance Not available

Text page icon Description of biotope

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

This tide-swept biotope is characterized by Halidrys siliquosa, which is often dense and is typically mixed with other kelps including Laminaria saccharina, Laminaria hyperborea and Saccorhiza polyschides. Below the canopy is an undergrowth of foliose red seaweeds which are tolerant of sand scour. There may be a rich epibiota on the Halidrys siliquosa plants, including Aglaophenia pluma, ascidians including Botryllus schlosseri, and sponges. This biotope may occur on the open coast or in rapids areas, and is distinguished from MIR.XKScrR by its greater scour. (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Additional information icon Additional information

Little information on the ecology of this biotope was found. The ecology has been inferred from general studies of subtidal macroalgal communities (see Brawley, 1992; Hawkins et al., 1992; Vadas & Elner, 1992; Williams & Seed, 1992; Schiel & Foster, 1986).

This review can be cited as follows:

Tyler-Walters, H. 2002. Halidrys siliquosa and mixed kelps on tide-swept infralittoral rock with coarse sediment.. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 26/11/2015]. Available from: <>