Rockpooling destination: Mousehole area, April 2014

The shore consists of a shelving bedrock platform with crevices and rock pools. Lichens occur in the splash zone and extend into the upper shore. Ephemeral green seaweeds occur in crevices and upper shore pools; whilst the mid and lower shore is characterised by barnacles and robust fucoids.

Habitat classifications:

Substrate	LR (Littoral rock)
Habitat	LR.HLR (High energy littoral rock)	FLR (Features of littoral rock)
Biotope complex	LR.HLR. MusB (Mussel and/or barnacle communities)	LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock).		LR.FLR.Rkp (Rockpools)
Biotope		LR.FLR.Lic.Ver (Verrucaria Maura on littoral fringe rock)	LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock)	LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools)	LR.FLR.Rkp.G        (Green seaweeds (Entomorpha spp. and Cladophora spp.) in shallow upper shore rock pools)

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

The rockyshore comprises bedrock with crevices and rockpools. Habitat classification: LR.HLR. MusB (Mussel and/or barnacle communities), LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock) and LR.FLR.Rkp (Rockpools).

Lichens occur throughout the splash zone. Habitat classification: LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock).

Lichens in the splash zone, include the spiky Sea ivory (Ramalina siliquosa).

Lichen

Lichens

Common orange lichen (Xanthoria parietina)

Those rock pools just below the splash zone are too hostile to support ephemeral seaweeds and instead gammarid amphipods are the obvious macrofauna. Habitat classification: LR.FLR.Rkp (Rockpools).

A gammarid amphipod in an uppershore rockpool.

The rockpools of the upper shore experience fluctuations in salinity and temperature that restrict gastropod density allowing the prolific growth of ephemeral green seaweeds: Habitat classification: LR.FLR.Rkp.G  (Green seaweeds (Entomorpha spp. and Cladophora spp.) in shallow upper shore rock pools).

Ulva sp (previously Entomorpha sp) growth is restricted to the rockpools and crevices.

Ulva sp dominated rock pool of the upper shore. The edges of the rock pool appear white from the Ulva sp becoming bleached from the sun as the water level of the rock pool decreases.

Tar lichen (Verrucaria Maura) covers the rocks of the upper shore. Habitat classification: LR.FLR.Lic.Ver (Verrucaria Maura on littoral fringe rock).

Small periwinkles (Melarhaphe neritoides) occur within the V. maura biotope.

The shore exhibits a gradient in barnacle density, increasing toward the low water mark. Patches of the lichen, Lichina pygmaea occur throughout the mid shore. Habitat classification: LR.HLR. MusB (Mussel and/or barnacle communities).

The lichen, Lichina pygmaea provides refuge for small periwinkles (Melarhaphe neritoides).

Spiral wrack (Fucus spiralis) and barnacles on the mid shore.

Spiral wrack (Fucus spiralis) grows amongst the barnacles.

The spiral wrack (Fucus spiralis) exhibits a thickened stipe to resist wave action.

The density of the spiral wrack (Fucus spp) increases toward sheltered platforms of the mid and lower shore.

Small individuals of common mussels (Mytilus edulis) also find refuge with the small periwinkles (Melarhaphe neritoides) amongst the barnacles.

The dead tests of barnacles provide a refuge for limpets (Patella sp), Small periwinkles (Melarhaphe neritoides) and the young growth stages of Spiral wrack (Fucus spp).

A Dog whelk (Nucella lapillus) and Limpet (Patella sp) occur amongst barnacles whilst small periwinkles (Melarhaphe neritoides) seek refuge within the dead barnacle tests.

Beadlet anemones (Actinia equina), Dog whelks (Nucella lapillus) and limpets (Patella sp) occur within a small coralline pool with coral weed (Corallina officinalis) and Corallinaceae crusts. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools).

A coralline dominated rock pool with coral weed (Corallina officinalis), Corallinaceae crusts, Limpets (Patella sp) and ephemeral seaweeds.

Ephemeral green seaweeds grow on the shells of limpets, where they avoid grazing from other limpets!