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Marine Habitat Classification

Description of biotope or habitat type

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   Nephtys hombergii and Tubificoides spp. in variable salinity infralittoral soft mud

Physical habitat description

Salinity Variable (18-35 ppt)
Wave exposure Moderately exposed, Sheltered
Tidal streams Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Mud; sandy mud
Zone Infralittoral
Depth Band 0-5 m, 5-10 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.SMu.SMuVS.NhomTubi <I>Nephtys hombergii</I> and <I>Tubificoides</I> spp. in variable salinity infralittoral soft mud

  • 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.


Variable salinity soft infralittoral mud and sandy mud characterised by the polychaete Nephtys hombergii and oligochaetes of the genus Tubificoides. Other characterising species that may be present are the polychaetes Streblospio shrubsolii and Aphelochaeta marioni, and the cumacean Diastylis rathkei typica.


The biotope is found in areas of silt deposition in soft and sandy muds but may not form a stable habitat. It may be found adjacent to AphTubi, separated by the abundance of Aphelochaeta marioni and its more cohesive sediments

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
Nephtys hombergii 44 Common 112 81-100 %
Scoloplos armiger 1 Abundant 35 21-40 %
Streblospio shrubsolii 8 Common 92 41-60 %
Aphelochaeta marioni 5 Frequent 65 41-60 %
Tubificoides 7 Common 243 21-40 %
Tubificoides amplivasatus 20 Common 271 41-60 %
Tubificoides benedii 2 Frequent 74 21-40 %
Diastylis rathkei typica 8 Common 48 41-60 %
Hydrobia ulvae 2 Frequent 17 21-40 %

Similar biotopes or habitat types

This biotope may be an impoverished version of AphTubi and can be distinguished by the abundance of A. marioni, terebellids and the stability of the sediment in AphTubi, together with the importance of associated species such as Diastylis rathkei typica in NhomTubi and species such as Caulleriella zetlandica in AphTubi.

The more mobile muds (MoMu) may contain a reduced element of this biotope in which case only sediment description will distinguish the two biotopes.

This biotope may also be allied with NhomMac which is found in more marine conditions and can be distinguished by the abundance of Macoma balthica and weaker tidal streams.

Classification history of this biotope or habitat type

Classification version Code
97.06 IMU.NhomTub

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