Biodiversity & Conservation

Fucus serratus with sponges, ascidians and red seaweeds on tide-swept lower eulittoral mixed substrata


<i>%Fucus serratus%</i> with sponges, ascidians and red seaweeds on tide-swept lower eulittoral mixed substrata
Distribution map

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

  • UK_BAP

For a list of 2004 characterising species please see the JNCC website.

Species indicative of sensitivity

To assess the sensitivity of the biotope, the sensitivity of component species is reviewed. Those species that are considered to be particularly indicative of the sensitivity of the biotope, and for which research has been undertaken in detail are shown below (see selection criteria). The biology of other component species of the biotope is also taken into account wherever information is known to the researcher.

Community Importance Species name Common Name
Important characterizing Fucus serratus Toothed wrack
Important characterizing Halichondria panicea Breadcrumb sponge
Important characterizing Ascidiella aspersa A sea squirt
Important characterizing Chondrus crispus Carrageen
Important other Lanice conchilega Sand mason
Important other Crepidula fornicata Slipper limpet
Important other Littorina littorea Common periwinkle
Important other Mytilus edulis Common mussel


The toothed wrack Fucus serratus gives the biotope its name and is therefore important for characterizing this biotope. This biotope is associated with a diverse fauna, dominated by a wide range of suspension feeders. The breadcrumb sponge Halichondria panicea (that occurred in every record of this biotope) and sea squirt Ascidiella aspersa have been listed as important characterizing species as they are representative of the sponges and ascidians that give the biotope its name. Carrageen Chondrus crispus is listed to represent a variety of red seaweeds that may be found in this biotope, although this species was the red seaweed found most frequently in records of this biotope. The common mussel Mytilus edulis, slipper limpet Crepidula fornicata and sand mason worm Lanice conchilega have been included as other important species because they are frequently associated with this biotope and they represent suspension feeders from another two phyla. Littorina littorea, a herbivore, was found in almost all of the records of this biotope and, accordingly, has also been listed as another important species.

Additional information

The MNCR recorded 423 species in 22 records of this biotope although not all of the species occurred in all records of the biotope (JNCC, 1999).

This review can be cited as follows:

Marshall, C.E. 2006. Fucus serratus with sponges, ascidians and red seaweeds on tide-swept lower 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 28/11/2015]. Available from: <>