Saturday 9 May 2015

Rockpooling Destination: Mousehole, December 2014




The shore comprises bedrock with gullies, crevices and rockpools. The variability in the bedrock topography results in a patchy distribution of habitats. Lichens occur in the splash zone and extend into the upper shore with periwinkles, channel wrack and sparse barnacles, the latter increasing in density toward the lower shore. Rockpools occur across the shore supporting variable communities depending on their position.


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

The rocky shore comprises bedrock with gullies, crevices and rockpools. Habitat classification:LR.HLR. MusB (Mussel and/or barnacle communities),  LR.FLR.Rkp (Rockpools), LR.LMR.BF.PelB (Pelvetia canaliculata and barnacles on moderately exposed shores), LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock). 


Channel wrack (Pelvetia canaliculata) forms a distinct band on the upper shore where it overgrows the tar lichen (Verrucaris maura). Habitat classification: LR.LMR.BF.PelB (Pelvetia canaliculata and barnacles on moderately exposed shores) EUNIS A1.211. 

 Barnacles and Small periwinkles (Melarhaphe neritoides), the latter seek refuge within the dead barnacle tests of the upper shore.

Sparse barnacles and  M. neritoides on the upper shore.

A rough periwinkles (Littorina spp) seeks refuge within a depression of the upper shore rock.

A rough periwinkles (Littorina spp) seeks refuge within a depression of the upper shore rock.


A rockpool of the upper shore with ephemeral green seaweed (Ulva sp) and Edible periwinkles (Littorina littorea). Habitat classification: LR.FLR.Rkp (Rockpools) EUNIS:A1.41.


Barnacle and common limpets (Patella vulgata) characterise the exposed rock of the mid and lower shore  Habitat classification: LR.HLR. MusB (Mussel and/or barnacle communities).
P. vulgata and barnacles
M. neritoides can also be found among the barnacles of the mid and lower shore.


The lichen, Lichina pygmaea, amongst barnacles.


The shelving nature of the bedrock results in high topographic heterogeneity which, in turn provides greater shelter form the oncoming waves. Notice how barnacle abundance is higher on the leeward sides of the shelves.


Small pits in the rock also provide shelter from the waves and in the case of this particular shore, support small individuals of the common blue mussel (Mytilus edulis).
Large shallow coralline rockpools occur from the mid shore down. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) EUNIS A1.411.

Further down on the lower shore the brown seaweed, Birurcaria bifurcata grows in the coralline rock pools . Habitat classification: LR.FLR.Rkp.Cor.Bif (Bifurcaria bifurcata in shallow eulittoral rockpool) EUNIS: A1.4113.


Bifurcaria bifurcata

Corallina officinalis

A variety of red seaweed species can be found amongst these rockpools.

Gastropod diversity also increases within the pools and includes, Edible periwinkles (Littorina littorea), Thick topshells (Osilinus lineatus) and flat topshells (Gibbula umilicus).

The invasive sargassum muticum can also be found. Submitting records of such sightings to organisations such as MarLIN or, your local recording centre can enable the spread of invasive species to be tracked.




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