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Marine Habitat Classification


Description of biotope or habitat type

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   Alcyonium digitatum and Metridium senile on moderately wave-exposed circalittoral steel wrecks


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Artificial, wrecks
Zone Circalittoral - lower
Depth Band 10-20 m, 20-30 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 CR.FCR.FouFa.AdigMsen <I>Alcyonium digitatum</I> and <I>Metridium senile</I> on moderately wave-exposed circalittoral steel wrecks

  • 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.

Description

This biotope is found on moderately wave-exposed circalittoral steel wrecks that are subject to moderately strong to weak tidal streams. The vertical and upward facing sides of the wreck stand proud of the seabed, and may be colonised by dense aggregations of Alcyonium digitatum, Metridium senile and Actinothoe sphyrodeta. Caryophyllia smithii and Corynactis viridis are also recorded with varying abundance. A mixed faunal turf may also be present on the vertical sides, with Nemertesia antennina, Flustra foliacea and Bugula plumosa. Where tidal stream strength is elevated, for example if the wreck is situated in a straight or sound, the hydroid Tubularia indivisa may prevail. Crustaceans such as the crabs Necora puber, Maja squinado and Cancer pagurus, the lobster Homarus gammarus and barnacles are all recorded. The top shell Calliostoma zizyphinum is also recorded.

Situation

No situation data available.

Temporal variation

No temporal variation data available.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Hydrozoa 4 Frequent 21-40 %
Tubularia indivisa 2 Common 1-20 %
Nemertesia antennina 2 Occasional 21-40 %
Alcyonium digitatum 24 Occasional 81-100 %
Metridium senile 16 Common 61-80 %
Actinothoe sphyrodeta 8 Occasional 61-80 %
Corynactis viridis 1 Occasional 21-40 %
Caryophyllia smithii 2 Occasional 21-40 %
Cirripedia 3 Frequent 21-40 %
Homarus gammarus 2 Rare 21-40 %
Maja squinado 8 Occasional 41-60 %
Cancer pagurus 7 Rare 61-80 %
Necora puber 10 61-80 %
Calliostoma zizyphinum 1 Occasional 21-40 %
Flustra foliacea 3 Occasional 21-40 %
Bugula plumosa 1 Frequent 1-20 %

Similar biotopes

Not applicable or unknown.

Photos

CR.FCR.FOUFA.AdigMsen Alcyonium digitatum and Metridium senile on moderately wave-exposed circalittoral steel wrecks, MV Robert, Lundy. Chris Lumb © JNCC
CR.FCR.FOUFA.AdigMsen Alcyonium digitatum and Metridium senile on moderately wave-exposed circalittoral steel wrecks, MV Robert, Lundy. Chris Lumb © JNCC
CR.FCR.FOUFA.AdigMsen Alcyonium digitatum and Metridium senile on moderately wave-exposed circalittoral steel wrecks, MV Robert, Lundy. Chris Lumb © JNCC
CR.FCR.FOUFA.AdigMsen Alcyonium digitatum and Metridium senile on moderately wave-exposed circalittoral steel wrecks, MV Robert, Lundy. Chris Lumb © JNCC

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