Antedon spp., solitary ascidians and fine hydroids on sheltered circalittoral rock

English name: Antedon spp., solitary ascidians and fine hydroids on sheltered circalittoral rock

Quick facts

EUNIS habitat type code A4.313
Bern Convention Included in a Resolution 4 habitat type at a higher level (A4)

Description (English)

This biotope is typically found on silty boulder or rock slopes, in the sheltered parts of sealochs, subject to weak or very weak tidal currents. The seabed consists of smooth, silty bedrock or boulders, often as outcrops on mixed muddy sediment. There are often small vertical faces on the sides of rock ridges, and at few sites, there may be more extensive steep or vertical bedrock. In sharp contrast to the barren, grazed appearance of A4.3111, the species composition of unit A4.313 is quite diverse, although no one phyla dominates. A wide range of encrusting species may be found, including the brachiopod Neocrania anomala, the saddle oyster Pododesmus patelliformis, encrusting red algae and polychaetes (Pomatoceros triqueter and Protula tubularia). Other conspicuous species include crinoids on the tops of boulders (Antedon bifida, commoner in shallower water and Antedon petasus, commoner in deeper water), scattered solitary and colonial ascidians (Ascidia mentula, Ascidia virginea, Corella parallelogramma, Clavelina lepadiformis and Ciona intestinalis) and tufts of fine hydroids (Kirchenpaueria pinnata, Nemertesia antennina, Obelia dichotoma and Halceum halecinum). The cup coral Caryophyllia smithii and the crustose bryozoan Parasmittina trispinosa are all typically present, as are a wide range of echinoderms, including the sea urchin Echinus esculentus, the starfish Asterias rubens and Crossaster papposus, and the brittlestars Ophiothrix fragilis and Ophiura albida. Other species recorded are the squat lobster Munida rugosa, the hermit crab Pagurus bernhardus and the chiton Tonicella marmorea.
Situation: The range of biotopes shallower and deeper than A4.313 is typical of a sheltered sealoch. Silted kelp biotopes (e.g. units A3.312, A3.313) are typically found shallower than A4.313 in the infralittoral zone. Deeper than A4.313, the boulder slope typically grades into a muddy slope or plain (units A5.3 or A5.4), along with fauna commonly associated with soft-sediments (e.g. seapens and the mud snail Turritella).

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Antedon bifida
Invertebrates Antedon petasus
Invertebrates Ascidia mentula
Invertebrates Ascidia virginea
Invertebrates Asterias rubens
Invertebrates Caryophyllia smithii
Invertebrates Ciona intestinalis
Invertebrates Clavelina lepadiformis
Invertebrates Corella parallelogramma
Invertebrates Crossaster papposus
Invertebrates Echinus esculentus
Invertebrates Kirchenpaueria pinnata
Invertebrates Munida rugosa
Invertebrates Nemertesia antennina
Invertebrates Neocrania anomala
Invertebrates Obelia dichotoma
Invertebrates Ophiothrix fragilis
Invertebrates Ophiura albida
Invertebrates Pagurus bernhardus
Invertebrates Parasmittina trispinosa
Invertebrates Pododesmus patelliformis
Invertebrates Pomatoceros triqueter
Invertebrates Protula tubularia
Invertebrates Tonicella marmorea
Species scientific name English common name Species group
Antedon bifida Invertebrates
Antedon petasus Invertebrates
Ascidia mentula Invertebrates
Ascidia virginea Invertebrates
Asterias rubens Invertebrates
Caryophyllia smithii Invertebrates
Ciona intestinalis Invertebrates
Clavelina lepadiformis Invertebrates
Corella parallelogramma Invertebrates
Crossaster papposus Invertebrates
Echinus esculentus Invertebrates
Kirchenpaueria pinnata Invertebrates
Munida rugosa Invertebrates
Nemertesia antennina Invertebrates
Neocrania anomala Invertebrates
Obelia dichotoma Invertebrates
Ophiothrix fragilis Invertebrates
Ophiura albida Invertebrates
Pagurus bernhardus Invertebrates
Parasmittina trispinosa Invertebrates
Pododesmus patelliformis Invertebrates
Pomatoceros triqueter Invertebrates
Protula tubularia Invertebrates
Tonicella marmorea Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 CR.LCR.BrAs.AntAsH <I>Antedon</I> spp., solitary ascidians and fine hydroids on sheltered circalittoral rock 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 A4.313 Antedon spp., solitary ascidians and fine hydroids on sheltered circalittoral rock same
EUNIS Habitat Classification 200308 A3.711 Antedon spp., solitary ascidians and fine hydroids on sheltered circalittoral rock same
EUNIS Habitat Classification 200202 A3.711 Antedon spp., solitary ascidians and fine hydroids on sheltered circalittoral rock same
EUNIS Habitat Classification 199910 A3.711 Antedon spp., solitary ascidians and fine hydroids on sheltered circalittoral rock same
MNCR BioMar 97.06 (Britain & Ireland) SCR.BrAs.AntAsH Antedon spp., solitary ascidians and fine hydroids on sheltered circalittoral rock same
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