EUNIS habitat classification 2012 amended 2019 > A - Marine habitats > A5 - Sublittoral sediment > A5.3 - Sublittoral mud > A5.36 - Circalittoral fine mud > A5.361 - Seapens and burrowing megafauna in circalittoral fine mud

Seapens and burrowing megafauna in circalittoral fine mud

English name: Seapens and burrowing megafauna in circalittoral fine mud

Quick facts

EUNIS habitat type code A5.361
Bern Convention Included in a Resolution 4 habitat type at a higher level (A5)

Description (English)

Plains of fine mud at depths greater than about 15 m may be heavily bioturbated by burrowing megafauna; burrows and mounds may form a prominent feature of the sediment surface with conspicuous populations of seapens, typically Virgularia mirabilis and Pennatula phosphorea. The burrowing crustacea present typically include Nephrops norvegicus, which is frequently recorded from surface observations although grab sampling may fail to sample this species. Indeed, some forms of sampling may also fail to indicate seapens as characterising species. This biotope also seems to occur in deep offshore waters in the North Sea, where densities of Nephrops norvegicus may reach 68 per 10 m2 (see Dyer et al. 1982, 1983), and the Irish Sea. The burrowing anemone Cerianthus lloydii and the ubiquitous epibenthic scavengers Asterias rubens, Pagurus bernhardus and Liocarcinus depurator are present in low numbers in this biotope whilst the brittlestars Ophiura albida and Ophiura ophiura are sometimes present, but are much more common in slightly coarser sediments. Low numbers of the anemone Pachycerianthus multiplicatus may also be found, and this species, which is scarce in the UK, appears to be restricted to this habitat (Plaza & Sanderson 1997). The infauna may contain significant populations of the polychaetes Pholoe spp., Glycera spp., Nephtys spp., spionids, Pectinaria belgica and Terebellides stroemi, the bivalves Nucula sulcata, Corbula gibba and Thyasira flexuosa, and the echinoderm Brissopsis lyrifera.
Situation: These soft mud habitats occur extensively throughout the more sheltered basins of sealochs and voes (narrow inlets) and are present in quite shallow depths (as little as 15 m) in these areas probably because they are very sheltered from wave action.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Asterias rubens
Invertebrates Brissopsis lyrifera
Invertebrates Corbula gibba
Invertebrates Liocarcinus depurator
Invertebrates Nephrops norvegicus
Invertebrates Nucula sulcata
Invertebrates Ophiura albida
Invertebrates Ophiura ophiura
Invertebrates Pachycerianthus multiplicatus
Invertebrates Pagurus bernhardus
Invertebrates Pectinaria belgica
Invertebrates Pennatula phosphorea
Invertebrates Thyasira flexuosa
Invertebrates Virgularia mirabilis
Species scientific name English common name Species group
Asterias rubens Invertebrates
Brissopsis lyrifera Invertebrates
Corbula gibba Invertebrates
Liocarcinus depurator Invertebrates
Nephrops norvegicus Invertebrates
Nucula sulcata Invertebrates
Ophiura albida Invertebrates
Ophiura ophiura Invertebrates
Pachycerianthus multiplicatus Invertebrates
Pagurus bernhardus Invertebrates
Pectinaria belgica Invertebrates
Pennatula phosphorea Invertebrates
Thyasira flexuosa Invertebrates
Virgularia mirabilis Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 SS.SMu.CFiMu.SpnMeg Seapens and burrowing megafauna in circalittoral fine mud source
CORINE Land Cover 5.2.3. Sea and ocean n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A5.361 Seapens and burrowing megafauna in circalittoral fine mud same
EUNIS Habitat Classification 200308 A4.362 Seapens and burrowing megafauna in circalittoral soft mud same
EUNIS Habitat Classification 200202 A4.362 Seapens and burrowing megafauna in circalittoral muds same
EUNIS Habitat Classification 199910 A4.362 Seapens and burrowing megafauna in circalittoral muds same
EUNIS Habitat Classification 199811 A4.82 Virgularia mirabilis and Pennatula phosphorea and burrowing megafauna of circalittoral muds same
EUNIS Habitat Classification 199712 A6.32 Seapens Nephrops norvegicus and burrowing megafauna of circalittoral muds same
MNCR BioMar 97.06 (Britain & Ireland) CMU.SpMeg Seapens and burrowing megafauna in circalittoral soft mud same
MNCR BioMar 96.7 (Britain & Ireland) CMU.SpNep   same
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