Biodiversity & Conservation

Hediste diversicolor and Macoma balthica in sandy mud shores



Image Roger Covey - Upper shore mud with Hediste holes and tracks. Image with ca XX cm.
Image copyright information

Distribution map

LS.LMU.SMu.HedMac 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 Recorded from estuaries all around mainland Britain. There are no records from Ireland although the biotope would be expected to occur here.
National importance Common

Text page icon Description of biotope

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

Littoral sandy mud and mud in sheltered, often estuarine, conditions with a community of polychaetes together with the bivalve Macoma balthica. The most abundant large polychaete is typically Hediste (Nereis) diversicolor, which can be readily seen when digging over the sediment. Other smaller polychaetes include Eteone longa, Nephtys hombergii, Aphelochaeta marioni, Pygospio elegans, Arenicola marina and Manayunkia aestuarina. Oligochaete worms (e.g. Tubificoides benedii, Tubificoides pseudogaster and enchytraeids) are common or abundant and the amphipod Corophium volutator may be abundant. The mud snail Hydrobia ulvae is often common, with individuals or their fine tracks visible on the mud surface. The bivalve Macoma balthica may be accompanied by Cerastoderma edule, Abra tenuis and Mya arenaria. The surface of the mud may be covered with green algae such as Ulva spp. or Ulva lactuca. There is usually a black anoxic layer close to the sediment surface. LMU.HedStr is a similar biotope that is associated with muddier sediment in reduced salinity conditions with Streblospio shrubsolii, Manayunkia aestuarina or Tharyx killariensis and with fewer bivalves. Three variations of this biotope are recognised: LMU.HedMac.Are, LMU.HedMac.Pyg and LMU.HedMac.Mare. (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:

Rayment, W.J. 2001. Hediste diversicolor and Macoma balthica in sandy mud shores. 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: <>