Skip to Content

Marine Habitat Classification

Description of biotope or habitat type

To understand more about what this page is describing, see How to use the classification. See also How to cite.

   Hesionura elongata and Microphthalmus similis with other interstitial polychaetes in infralittoral mobile coarse sand

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Exposed, Moderately exposed, Sheltered
Tidal streams Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Medium to very coarse sand
Zone Infralittoral
Depth Band 5-10 m, 10-20 m
Other Features

Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.

Distribution of habitat SS.SCS.ICS.HeloMsim <I>Hesionura elongata</I> and <I>Microphthalmus similis</I> with other interstitial polychaetes in infralittoral mobile coarse sand

  • Records used to define the biotope (core records)
  • Other records assigned to this biotope, marked as 'certain'
  • Other records assigned to this biotope, marked as 'uncertain'
  • Predicted extent of the level 3 (for sublittoral rock & deep sea) or 4 (for sublittoral sediment) habitat

Point data based on records in the UK Marine Recorder Snapshot. Predicted habitat extent is from UKSeaMap.


On infralittoral sandbanks and sandwaves and other areas of mobile medium-coarse sand, populations of interstitial polychaetes may be found. These habitats consist of loosely packed grains of sand forming waves up to several metres high often with gravel, or occasionally silt, in the troughs of the waves. This biotope is commonly found both inshore along the east coast of the UK e.g. around the Race Bank, Docking Shoal and Inner Dowsing banks (IECS, 1995; IECS, 1999), and in the Southern Bight of the North Sea and off the Belgian coast (Degraer et al. 1999; Vanosmael et al. 1982). These habitats support interstitial communities living in the spaces between the grains of sand, in particular hesionurid polychaetes such as Hesionura elongata and Microphthalmus similis, along with protodrilid polychaetes such as Protodrilus spp. and Protodriloides spp. Other important species may include Turbellaria spp. and larger deposit feeding polychaetes such as Travisia forbesii. An important feature of this biotope which is not reflected in much of the available data is the importance of the meiofaunal population which may exceed the macrofaunal population both in terms of abundance and biomass (Willems et al. 1982).


This biotope is commonly found both in shore adjacent to the coast, and further away from the coast.

Temporal variation

No temporal data available.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale Typical abundance - (count per m2) % of core records where taxon was recorded
Turbellaria 59 Common 140 41-60 %
Nemertea 4 Common 11 1-20 %
Hesionura elongata 4 Common 115 21-40 %
Glycera lapidum 3 6 21-40 %
Microphthalmus 2 Frequent 34 1-20 %
Microphthalmus similis 6 Frequent 73 21-40 %
Nephtys cirrosa 3 3 21-40 %
Travisia forbesii 5 Common 18 1-20 %
Protodrilus 4 Frequent 19 21-40 %
Protodriloidae 2 Common 6 1-20 %
Spisula elliptica 1 2 1-20 %

Similar biotopes or habitat types

More mobile and found on finer sediments than HeloMsim. More faunally impoverished as a result of this mobility.

NcirBat is found in finer sediments with a higher proportion of amphipod and isopod crustaceans

Glap has a gravel fraction and is more faunally impoverished

Pkef has a more varied sediment composition with a higher fine sand or silt fraction and high prevalence of Protodorvillea kefersteini

Back to top