Tuesday, 19 May 2015

Rockpooling Destination: Lamorna, December 2014

The shore is positioned within in a small cove, with a crumbled down harbour wall. Boulders back the cove giving way to sand on the lower shore and a river runs over and under the boulders down to the sea. The harbour wall had relatively recently fallen into disrepair and where the wall has broken down, slabs of rock that were once positioned in the sublittoral have been washed up the shore, to occupy a position in the intertidal. The result is that 'at present' species usually found in the subtidal can be seen in the intertidal.

The shore is comprised of boulders that give way to sand on the lower shore.

A strandline has formed on the sandy shore. Habitat classification: LS.LSa (Littoral sand) and  LS.LSa.St (Strandline) EUNIS: A2.21.

Periwinkles and sparse barnacles aggregate within crevices and pits of the boulders of the upper shore, whilst below ephemeral algae cover boulders that experience sand scour from the adjacent sand below. 

Small periwinkles (Melarhaphe neritoides), rough periwinkles (Littorina sp) and sparse barnacles aggregate in a crevice of a boulder. 
Small periwinkles (Melarhaphe neritoides), rough periwinkles (Littorina sp) and sparse barnacles aggregate in a crevice of a boulder.
Small periwinkles (Melarhaphe neritoides) utilize the pits of the boulder.
Small periwinkles (Melarhaphe neritoides) utilize the pits of the boulder.
Ephemeral green algae covers the boulders that are adjacent to the sand and experience sand scour. Habitat classification: Eph.FLR.Eph (Ephemeral green or red seaweed communities) EUNIS A1.45.

Ephemeral green algae

The red ephemeral algae, Porphyra sp also grows on the boulders affected by sand scour.

The harbour wall provides a hard substrate upon which organisms can grow and feed.

Damp conditions at the base of the harbour wall facilitate the growth of coralline crusts, red seaweeds, polychaete worm tubes and anemones, whilst above barnacles and mussels occur.
Small periwinkles (Melarhaphe neritoides), rough periwinkles (Littorina compressa) and sparse barnacles.

Limpets (Patella spp) and barnacles are the most prominant species of the harbour wall. Habitat classification: LR.HLR. MusB (Mussel and/or barnacle communities) EUNIS A1.11.

Other organisms are restricted to crevices and damp patches at the base of the harbour wall. Here a common blue mussel (Mytilus edulis)  exploits a crevice of the harbour wall.

Red seaweeds occur in patches on the lower extents of the harbour wall, Mastrocarpus stellatus

Mastrocarpus stellatus

A red seaweed

Barnacle and beadlet anemone  (Actina equina) abundance reaches its highest at a height on the wall where exposure and sand scour reach a trade off.

A damp area at the base of the wall facilitates the growth of Coralline crusts and limpets increase in abundance.

Spirobid polychaete worm tubes also occur within this damp patch.

Beadlet anemones (Actina equina) also occur on the cobbles beneath the harbour wall.
On parts of the harbour wall that have been washed up, sublittoral species are now found in the intertidal. Here you can see serpulid polychaete worm tubes.

 A chiton and serpulid polychaete  (Pomatoceros triqueter).

A chiton finds protection within a depression of the rock.


A serpulid worm tube (Pomatoceros triqueter)

Serpulid worm tubes  (Pomatoceros triqueter).
Gastropods aggregate within the protection of the serpulid  worm tube  (Pomatoceros triqueter).

Gastropods within Ulva spp.

A blue rayed limpet (Patella pellucida)

A limpet (Patella depressa)


Flat topshell (Gibbula umbilicus)


Barnacles (Balanus perforatus)
Limpets, rough periwinkles (Littorina compressa v nigrolineata), beadlet anemone (Actina equina), barnacles (Balanus perforatus) and Lomentaria articulata..

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.