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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.

   Aphelochaeta marioni and Tubificoides spp. in variable salinity infralittoral mud

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Cohesive mud and sandy mud, possibly with shell debris and stones
Zone Infralittoral
Depth Band 0-5 m, 5-10 m
Other Features

Biotope origin

Derived using data from Various
Faunal group Infauna

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.AphTubi <I>Aphelochaeta marioni</I> and <I>Tubificoides</I> spp. in variable salinity infralittoral 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 cohesive muddy sediment (sometimes with some coarser material) dominated by the polychaete Aphelochaeta marioni (or other Aphelochaeta species e.g. A. amplivasatus) and the oligochaete Tubificoides spp. These taxa are generally accompanied by Nephtys hombergii whilst the polychaetes Capitella capitata and Melinna palmata may also occur in high numbers in some areas. Other members of the cirratulid polychaete group, e.g. Chaetozone zetlandica and Tharyx spp. may also occur in high numbers, sometimes replacing A. marioni as the dominant polychaete. However, there is still inconsistency in the identification of the cirratulid group which is further compounded by fragmentation during sample processing. This biotope is very common in stable muddy environments and may extend from reduced salinity to fully marine conditions.


This biotope may also be found in conjunction with SS.SMu.ISaMu.NhomMac.

Temporal variation

No temporal data available.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Polychaeta 71 21-40%
Aphelochaeta marioni 33 Abundant 61-80%
Cardiidae 18 1-20%
Nephtys hombergii 9 Common 61-80%
Tharyx 9 Abundant 21-40%
Crepidula fornicata 7 1-20%
Tubificoides swirencoides 7 Common 41-60%
Carcinus maenas 4 Rare 1-20%
Tubificoides benedii 4 Frequent 41-60%
Tubificoides pseudogaster 3 Common 21-40%
Capitella capitata 2 Frequent 41-60%
Chaetozone zetlandica 2 Common 21-40%
Exogone naidina 2 Frequent 21-40%
Melinna palmata 2 Common 21-40%
Streblospio shrubsolii 2 Frequent 21-40%
Cerastoderma edule 1 21-40%
Abra nitida 1 Common 21-40%
Ampharete 1 Common 21-40%
Mediomastus fragilis 1 Frequent 21-40%
Nephtys 1 Common 21-40%
Phoronis muelleri 1 Frequent 21-40%
Polydora ciliata 1 Common 21-40%
Pygospio elegans 1 21-40%
Scoloplos armiger 1 21-40%

Similar biotopes or habitat types

The current biotope may be more diverse version of SS.SMu.SMuVS.NhomTubi and can be distinguished by the abundance of A. marioni, terebellids and the stability of the sediment in SS.SMu.SMuVS.AphTubi, together with the importance of associated species such as Diastylis rathkei typica in SS.SMu.SMuVS.NhomTubi.

It may be separated from SS.SMx.SMxVS.CreMed by the relative abundances of the slipper limpet Crepidula fornicata in addition to A. marioni.

In areas of mixed sediment A. marioni may also occur in high numbers. In this case it may be difficult to separate SS.SMu.SMuVS.AphTubi from SS.SMx.SMxVS.AphPol requiring classification on sediment characteristics and associated species in addition to the abundance of A. marioni.

Where SS.SMu.SMuVS.AphTubi occurs in polyhaline waters it may grade into the biotope SS.SMu.ISaMu.MelMagThy as the salinity increases e.g. in the Fal estuary (Allen et al. 2002).

Classification history of this biotope or habitat type

Classification version Code Habitat name
2015 (15.03) SS.SMu.SMuVS.AphTubi Aphelochaeta marioni and Tubificoides spp. in variable salinity infralittoral mud
2004 (04.05) SS.SMu.SMuVS.AphTubi Aphelochaeta marioni and Tubificoides spp. in variable salinity infralittoral mud
1997 (97.06) SS.IMU.EstMu.AphTub Aphelochaeta marioni and Tubificoides spp. in variable salinity infralittoral mud
1996 (6.95) IMU.PhoSco

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