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SS.SCS.CCS.MedLumVen
Mediomastus fragilis, Lumbrineris spp. and venerid bivalves in circalittoral coarse sand or gravel

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Habitat (physical) description

Distribution

 Salinity: Full (30-35 ppt) 
 Wave exposure: Exposed, Moderately exposed 
 Tidal streams: Moderately strong (1-3 kn), Weak (>1 kn) 
 Substratum: Gravel with coarse to medium sand 
 Zone: Circalittoral 
 Depth Band: 10-20 m, 20-30 m, 30-50 m, 50-100 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.CCS.MedLumVen  Mediomastus fragilis, Lumbrineris spp. and venerid bivalves in circalittoral coarse sand or gravel
Distribution of habitat SS.SCS.CCS.MedLumVen Mediomastus fragilis, Lumbrineris spp. and venerid bivalves in circalittoral coarse sand or gravel, 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

Circalittoral gravels, coarse to medium sands, and shell gravels, sometimes with a small amount of silt and generally in relatively deep water (generally over 15-20m), may be characterised by polychaetes such as Mediomastus fragilis, Lumbrineris spp., Glycera lapidum with the pea urchin Echinocyamus pusillus. Other taxa may include Nemertea spp., Protodorvillea kefersteini, Owenia fusiformis, Spiophanes bombyx and Amphipholis squamata along with amphipods such as Ampelisca spinipes. This biotope may also be characterised by the presence of conspicuous venerid bivalves, particularly Timoclea ovata. Other robust bivalve species such as Moerella spp., Glycymeris glycymeris and Astarte sulcata may also be found in this biotope. Spatangus purpureus may be present especially where the interstices of the gravel are filled by finer particles, in which case, Gari tellinella may also be prevalent (Glemarec 1973). Venerid bivalves are often under-sampled in benthic grab surveys and as such may not be conspicuous in many infaunal datasets. Such communities in gravelly sediments may be relatively species-rich and they may also contain epifauna such as Hydroides norvegicus and Pomatoceros lamarcki. In sand wave areas this biotope may also contain elements of the FfabMag biotope, particularly Magelona species. This biotope has previously been described as the 'Deep Venus Community' and the 'Boreal Off-Shore Gravel Association' by other workers (Ford 1923; Jones 1950) and may also be part of the Venus community described by Thorson (1957) and in the infralittoral etage described by Glemarec (1973). SCS.MedLumVen may be quite variable over time and in fact may be closer to a biotope complex in which a number of biotopes or sub-biotopes may yet be defined. For example, Ford (1923) describes a 'Series A' and a 'Series B' characterised by Echinocardium cordatum-Chamelea gallina and Spatangus purpurea-Clausinella fasciata. Furthermore, mosaics of cobble and lag gravel often contain ridges of coarse gravelly sand and these localised patches are also characterised by robust veneriid and similar bivalves including Arcopagia crassa, Laevicardium crassum and others including Glycymeris glycymeris (E.I.S. Rees pers. comm.. 2002). This high porosity fine gravel or coarse sand may be a separate biotope.

Situation

This biotope and variants of it make up a significant proportion of the offshore Irish Sea benthos (Mackie, Oliver & Rees 1995).

Temporal variation

MedLumVen may be quite variable over time.

Similar biotopes

SS.SCS.ICS.MoeVenMoeVen is the shallow water variant of the current biotope
SS.SCS.CCS.PkefPkef is more impoverished and less diverse than MedLumVen. It is possible that Pkef is a disturbed or transitional variant of MedLumVen resulting from dredging activities or storm events.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity Abundance (no.2)
Actiniaria C 2 182
Nemertea C 5 55
Glycera lapidum C 5 47
Sphaerosyllis P 1 21
Lumbrineris gracilis C 10 98
Protodorvillea kefersteini P 3 42
Poecilochaetus serpens P 1 18
Spiophanes bombyx F 4 27
Mediomastus fragilis F 11 130
Owenia fusiformis P 4 21
Lanice conchilega O 29
Pista cristata A 1 25
Ampelisca spinipes F 2 21
Pagurus bernhardus F 35
Pecten maximus O 7
Abra alba C 2 54
Timoclea ovata C 2 30
Corbula gibba F 2 27
Cochlodesma praetenue C 2 21
Asterias rubens O 29
Amphipholis squamata A 3 67
Echinocyamus pusillus C 13 63

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