Rock Pooling: Rockpooling destination: St. Martins Flats, Isles of Scilly April 2014

The shore comprises outcrops of bedrock and boulders amongst vast expanses of sandon the lower shore.

Fucoids form a blanket across the rock, with dense ephemeral green alga and the occasional fucoid on the small cobbles toward the edges of the outcrops.

Periwinkles, limpets and topshells occur across the outcrop with anemones, crabs, spirorbid polychaetes and red seaweeds beneath the fucoid understorey.

Habitat classification:

Substrate	LR (Littoral rock)					LS (Littoral substrate)
Habitat	LLR (Low energy littoral rock)			FLR (Features of littoral rock)		LS.LSa (Littoral sand)
Biotope complex	LR.LLR.F (Fucoids on sheltered marine shores)			Eph.FLR.Eph (Ephemeral green or red seaweed communities	Rkp (Rockpools)
	LR.MLR.BF.Fser.Bo (Fucus serratus and under boulder fauna on lower eulittoral boulders).	LR.LLR.F.Asc .FS (Ascophyllum nodosum on full salinity rock)	LR.LLR.F.Fserr (Fucus serratus on sheltered lower eulittoral rock).

Below are images of organisms you may encounter whilst rockpooling in this habitat:

The rocky shore is comprised of outcropping bedrock and boulders covered by fucoids and ephemeral green alga. Habitat classification: LR.LLR.F (Fucoids on sheltered marine shores) and LS.LSa (Littoral sand).

Rough periwinkles (Littorina saxatilis) occur on the higher rock of the outcrop.

Bladder wrack (Fucus vesiculosus) characterises the mid shore, whilst a mix of seaweeds can be found in rockpools. Habitat classification: LR.LLR.F (Fucoids on sheltered marine shores) and LR.FLR.Rkp (Rockpools).

Lower down Limpests (Patella vulgata) and Egg wrack (Ascophyllum nodosum) with its epiphyte Polysiphonia sp occur.

Eventually the Egg wrack (Ascophyllum nodosum) and occasional serrated wrack (Fucus serratus) comes to cover the rocks. Habitat classification: LR.LLR.F.Asc .FS (Ascophyllum nodosum on full salinity rock)

Carefully lifting the seaweed reveals the understorey community of red seaweeds, anemones, gastropods, crustaceans, spirorbid polychaetes and encrusting epifauna.

An understorey red seaweed.

Corallinaceae crusts cover much of the understorey rock.

Breadcrumb sponge (Halichondria (Halichondria) panicea).

Further down serrated wrack (Fucus serratus) comes to dominate. Here the young growth of f. serratus amongst the understorey reds can be seen. Habitat classification: LR.LLR.F.Fserr (Fucus serratus on sheltered lower eulittoral rock).

Serrated wrack (Fucus serratus).

Amongst the F. serratus and beneath the boulders is a rich faunal community, comprising an increased number of filter feeding species. Habitat classification: LR.MLR.BF.Fser.Bo (Fucus serratus and under boulder fauna on lower eulittoral boulders).

A Montagu's crab (Xantho hydrophilus) amongst seaweed and boulders of the lower shore.

An anemone and painted topshell (Calliostoma zizyphinum)

A seaspider carrying its eggs.

A Broad-clawed porcelain crab (Porcellana platycheles) on the underside of a boulder of the lower shore.

A wart barnacle (Verruca stroemia) on the underside of a boulder on the lower shore.

Encrusting epifauna, spirorbid polychaetes and wart barnacles (Verruca stroemia) on the underside of a boulder on the lower shore.

Encrusting epifauna, including spirorbid polychaetes and bryozoa, on the underside of a boulder on the lower shore.

An anemone on the side of a boulder on the lower shore.

A capitellid polychaete.

Ephemeral green algae and brown seaweed grow on the mixed substrate surrounding the outcrop

At the low water mark, Thong weed (Himanthalia elongata) and red seaweeds come to dominate.

Boulders at the low tide mark are colonised by a variety of seaweed species including Serrated wrack (Fucus serratus), Chondus crispus , Osmoundea sp, Thong weed (Himanthalia elongata), Lomentaria articulata and sandbinder (Rhodothamniella floridula)

A red seaweed

Red seaweeds including,Chondus crispus and Ulva sp.

Serrated wrack (Fucus serratus), Chondus crispus , Osmoundea sp and sandbinder (Rhodothamniella floridula)

Osmoundea sp

Lomentaria articulata

Harpoon weed (Asparagopsis armata)

A close up of the epiphytic filamentous brown seaweed shows its fine frond structure.

Ceranium sp.

Ceranium sp

Creep horn (Chondracanthus acicularis)

A snakelocks anemone (Anemonia viridis)

Anemone

Away from the rocky shore outcrop great swaths of sand extend across the bay. Lugworm characterise areas of this sand habitat with their presence inferred from their casts.