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Marine Habitat Classification

Description of biotope or habitat type

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   Mysella bidentata and Abra spp. in infralittoral sandy mud

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Very sheltered
Tidal streams Very weak (negligible)
Substratum Muddy sands and sandy muds
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.ISaMu.MysAbr <I>Mysella bidentata</I> and <I>Abra</I> spp. in infralittoral sandy 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.


Cohesive sandy mud, sometimes with a small quantity of shell in shallow water may contain the bivalves Mysella bidentata and Abra spp. (typically A. alba and A. nitida). Other characteristic taxa may include Scoloplos armiger, Mya sp., and Thyasira flexuosa. Tube building amphipods are also characteristic of this biotope in particular Ampelisca spp. and Aoridae such as Microprotopus maculatus.


This biotope is generally found in sheltered marine inlets or sealochs such as Strangford Lough.

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
Nematoda 15 Frequent 81-100 %
Nephtys hombergii 2 Common 21-40 %
Nephtys kersivalensis 1 Common 21-40 %
Scoloplos armiger 10 Super abundant 61-80 %
Cirratulidae 2 Common 41-60 %
Capitella capitata 1 Frequent 21-40 %
Mediomastus fragilis 1 Frequent 21-40 %
Arenicola marina 1 21-40 %
Melinna palmata 1 Common 21-40 %
Dexamine thea 1 Frequent 41-60 %
Ampelisca brevicornis 6 Common 41-60 %
Ampelisca tenuicornis 2 Frequent 41-60 %
Microprotopus maculatus 2 Frequent 21-40 %
Aoridae 1 Frequent 41-60 %
Pariambus typicus 1 41-60 %
Thyasira flexuosa 2 61-80 %
Mysella bidentata 9 Frequent 81-100 %
Abra alba 11 Common 61-80 %
Abra nitida 2 Common 41-60 %
Mya 3 Common 61-80 %
Zostera marina 99 61-80 %

Similar biotopes or habitat types

MysAbr is similar to AmpPlon but differs in the variety and abundance of amphipods and is found in muddier sediments in sheltered sealochs such as Strangford Lough. It is possible that these two biotopes are actually part of a wider biotope which contains more than one entity depending on its geographic location and prevailing environmental conditions

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