Neocrania anomala and Protanthea simplex on sheltered circalittoral rock

Description (English)

This biotope typically occurs in full to variable salinity conditions on very wave-sheltered circalittoral bedrock and boulder slopes subject to negligible tidal streams (this tends to be in the landward, very sheltered basins of fjordic sealochs). This biotope is characterised by often dense populations of the anemone Protanthea simplex, growing on the silty bedrock. The underlying rock surfaces are usually covered by encrusting red algae, the polychaete Pomatoceros triqueter, the brachiopods Neocrania anomala and Terebratulina retusa, the saddle oyster Pododesmus patelliformis and the polychaete Sabella pavonina. Scattered colonies of Alcyonium digitatum and the hydroid Bougainvillia ramosa may occasionally be recorded. A diverse range of ascidians including Ciona intestinalis, Ascidia mentula, Corella parallelogramma, Ascidia virginea, Polycarpa pomaria and Dendrodoa grossularia are also occasionally recorded. Echinoderms such as the common brittlestar Ophiothrix fragilis are frequently reported with their arms protruding from crevices in the rock, whilst the starfish Asterias rubens, Henricia oculata, and the sea urchin Echinus esculentus and Psammechinus miliaris are occasionally found on the boulder/rock surface. The whelk Buccinum undatum is often present but in very low numbers. The squat lobster Munida rugosa may be seen hiding in crevices. The hermit crab Pagurus bernhardus may also be recorded.

Source: EUNIS habitat classification