Biodiversity & Conservation

Arenicola marina and synaptid holothurians in extremely shallow soft mud.



Image Anon. - Arenicola marina and synaptid holothurians in extremely shallow soft mud. Image width ca 40 cm in foreground.
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Distribution map

SS.SMu.IFiMu.Are recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

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.

Species found especially in this biotope

  • Arenicola marina
  • Labidoplax media
  • Leptosynapta bergensis
Community Importance Species name Common Name
Important characterizing Arenicola marina Blow lug
Important characterizing Labidoplax media A sea cucumber
Important characterizing Leptosynapta bergensis A sea cucumber


This biotope is characterized by the presence of Arenicola marina and the abundant synaptid holothurians such as Labidoplax media, Leptosynapta bergensis and Leptosynapta inhaerens. Arenicola marina does not reach high densities in soft, flocculent muds. Its abundance is variable in this biotope but may reach sufficient densities to modify the substratum with mounds and funnels in some instances of the biotope, however the blow lug was absent in one record of this biotope, a flocculent mud plain (JNCC, 1999).

Additional information

The MNCR recorded 292 species within this biotope, although not all are present in each instance of the biotope (JNCC, 1999).

This review can be cited as follows:

Tyler-Walters, H. 2001. Arenicola marina and synaptid holothurians in extremely shallow soft mud.. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 29/11/2015]. Available from: <>