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SS.SMu.IFiMu.PhiVir
Philine aperta and Virgularia mirabilis in soft stable infralittoral mud

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Habitat (physical) description

Distribution

 Salinity: Full (30-35 ppt), Variable (18-35 ppt) 
 Wave exposure: Sheltered, Very sheltered, Extremely sheltered 
 Tidal streams: Weak (>1 kn), Very weak (negligible) 
 Substratum: Mud occasionally with small stones 
 Zone: Infralittoral 
 Depth Band: 0-5 m, 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.SMu.IFiMu.PhiVir  Philine aperta and Virgularia mirabilis in soft stable infralittoral mud
Distribution of habitat SS.SMu.IFiMu.PhiVir Philine aperta and Virgularia mirabilis in soft stable infralittoral mud, based on records on the UK Marine Recorder database and EUSeaMap. Red dots represent records on which the biotope is based. Blue dots show other certain records, black dots show records tentatively assigned to this biotope. Yellow areas show level 2 and 3 sublittoral and deep-sea habitats prediced by EUSeaMap within UK waters.

Biotope description

Physically very stable muds, occasionally with small stones, with a high proportion of fine material (typically greater than 80 %) may contain the opisthobranch Philine aperta and the seapen Virgularia mirabilis. These muds typically occur in shallow water down to about 12-15 m where significant seasonal variation in temperature is presumed to occur. This habitat is restricted to the most sheltered basins in, for example, sealochs. Although most records suggest full salinity conditions are prevalent, some sites may be subject to variable salinity. Philine aperta is the most characteristic species of this habitat, occurring in high densities at many sites, whilst Virgularia mirabilis, a species found more widely in muddy sediments, appears to reach its highest densities in this shallow mud but may not be present in all examples of this biotope. Other conspicuous species found in this shallow muddy habitat include Cerianthus lloydii, Pagurus bernhardus, Sagartiogeton spp. and Hydractinia echinata. Burrowing crustacean megafauna, characteristic of deeper mud, are rare or absent from this shallow sediment although Nephrops norvegicus may sometimes be recorded. This biotope has been primarily recorded on the basis of its epifauna and a few conspicuous infauna. Little data exists on the infaunal component of this biotope but it may include Nephtys spp., spionid polychaetes, Ampelisca spp. and the bivalves Nucula spp., Thyasira flexuosa, Mysella bidentata and Abra spp. In the south of Great Britain, the polychaete Sternaspis scutata is also characteristic of this biotope. This polychaete is rare in Great Britain (Sanderson 1996). Indeed, this southern variant of the biotope is very restricted in the UK to Portland Harbour but is known to occur further south in the Gulf of Gascony and the Mediterranean (Glemarec 1973; Dauvin et al. 1994).

Situation

No situation data available.

Temporal variation

It is possible that this biotope is a temporal variant of other SMU biotopes. The key species, Philine aperta, may be highly variable from year to year The sediment may also be covered by a diatom film at certain times of the year

Similar biotopes

SS.SMu.CFiMu.SpnMegSpnMeg is similar to PhiVir, but occurs deeper, is more stable, and is characterised by burrowing megafauna and the sea pen Pennatula phosphorea
SS.SMu.CFiMu.BlyrAchiPhiVir displays some resemblance to BriAchi, but the latter is characterised by a high abundance of ophiuroid species particularly Amphiura spp.
SS.SMu.ISaMu.MysAbrPhiVir may be closely allied to MysAbr, possibly sharing some of the infaunal elements of this biotope. However MysAbr is found on sandier sediments
SS.SMu.ISaMu.SundAaspSundAasp appears to be an impoverished (disturbed?) version of PhiVir lacking in P. aperta and V. mirabilis.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity Abundance (no.2)
Hydractinia echinata O 4
Virgularia mirabilis F 8
Cerianthus lloydii F 7
Sagartiogeton laceratus O 1
Sagartiogeton undatus F 2
Terebellidae O 2
Pagurus bernhardus F 11
Liocarcinus depurator O 3
Carcinus maenas O 5
Philine aperta C 30
Aequipecten opercularis R 2
Asterias rubens O 5
Amphiura filiformis F 1
Ascidiella aspersa O 2
Pomatoschistus O 2
Laminaria saccharina R 1

Example photographs of biotope

No characteristic photos currently available. If you are able to provide a photograph of this biotope please contact .


Version 15.03 of the classification adds a deep-sea section to version 04.05; therefore superseding version 04.05, 97.06 and 03.02.

This online classification should be cited as:

JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed]. Available from: jncc.defra.gov.uk/MarineHabitatClassification

Information from the shallower section (up to sublittoral sediment, taken from Version 04.05) be cited as the report accompanying Version 04.05, as follows:

CONNOR, D.W., J.H. ALLEN, N.GOLDING, K.L.HOWELL, L.M. LIEBERKNECHT, K.O. NORTHEN AND J.B. REKER (2004) The Marine Habitat Classification for Britain and Ireland Version 04.05. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISBN 1 861 07561 8


Information from the deep-sea section (added in March 2015) should be cited as the report accompanying the deep-sea section, as follows:

PARRY, M.E.V., K.L. HOWELL, B.E. NARAYANASWAMY, B.J. BETT, D.O.B. JONES, D.J. HUGHES, N. PIECHAUD, T.D. NICKELL, H. ELLWOOD, N. ASKEW, C. JENKINS and E. MANCA (2015) A Deep-sea Section for the Marine Habitat Classification of Britain and Ireland. JNCC report 530. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISSN 0963 8901