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Arthropods - Crabs, Lobsters, Shrimps and
Barnacles |
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These are the rock pools at
Llanina Point at low tide.
Cei Bach Beach is in the background.
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Edible or Brown Crab
Cancer pagurus - The
much larger edible crab is seldom found in the intertidal zone
although juveniles may be found in rock pools or washed up on the
beach.
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Spider Crab
Maia squinado
The Spider Crabs come inshore from
deep water each summer. Often their shells (carapace or legs) can be found
washed up on the beach.
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Shore Crab
Carcinus maenas
- by far the most common crab - found under rocks at low tide. The
much larger edible crab is seldom found in the intertidal zone.
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Acorn Barnacles
Chthamalus stellatus
These tiny crustaceans lie on their backs inside their protective shell
plates waving their specialised legs in the air to catch plankton
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Common Prawn
Leander serratus
Almost transparent, they are common in rock pools
at low tide.
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Molluscs - these include the Bivalves ( 2 shells ),
the Gastropods ( 1 spiral
shell ) and the Octopus and Squid
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Common Periwinkle (Winkle)
Littorina Littoralis
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Limpets
Patella vulgata
The scientific name is the same as the kneecap which it resembles in shape.
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Mussels
Mytilus edulis
They are firmly stuck to the rock by a Byssus or cluster of strong threads.
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Mussels
Mytilus edulis
There are extensive
Mussel beds on the Carreg Ina rocks at Llanina Point. Cei Bach beach
is in the background.
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Common Periwinkle (Winkle)
Littorina Littoralis
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Razor Shell
Ensis arcuata
The Razor Shell is buried deep in the sand and only generally seen after it
has died .
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Top Shells
Gibbula species
shown here with Barnacles.
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Common Periwinkle (Winkle)
Littorina Littoralis
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Scallop
Pecten maximus mostly broken shells - probably from the fish factory to the west of the town
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Dogwhelks
Nucella lapilus
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Whelk
Buccinum undatum
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Whelk Eggs
Buccinum undatum
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Seaweeds - or Algae
are divided into three main groups according to their colour. They are
the Greens, the Browns and the Reds. Each group has a different pigment to
trap the energy of light
- the greens tend to be higher up the
shoreline, the browns and reds lower down with the larger browns
like Laminaria only growing at or below the low tide line.
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Chondrus crispus
This is a red seaweed called Carragheen Moss in
Ireland where it is eaten
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Serrated Wrack
Fucus serratus - a brown seaweed
covering much of the rocks between high and low tide
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Codium
Codium tomentosum - a green alga with
thick cylindrical stems.
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Enteromorpha
Grows
rapidly in the late spring and makes the rocks below the high tide
mark quite slippery.
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Dulse
This is a red edible seaweed
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Laver
Porphyra umbilicalis - used to make Laver Bread in Wales
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Furcellaria
another red seaweed
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Horn Weed
Flustra
foliacea
Not a seaweed at all
but a primitive animal belonging to the group Bryozoa.
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Kelp
Laminaria sacharina - the Kelps
and Oar weeds are very robust brown seaweeds firmly attached to the rocks by a
holdfast
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Kelp
Laminaria digitata
The stem or 'stipe' of this Kelp is very strong and flexible. They are only
broken away from the rocks by severe storms.
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Oar Weed
Saccorhiza polyschides
Another big 'Kelp' the Oarweed is easily identified by its bulbous base
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Bladder Wrack
Fucus vesiculosus has air filled
bladders which buoy up the fronds towards the light when they are
submerged. The swollen tips of the fronds are the reproductive
organs.
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Japanese Seaweed
an invasive and fast growing import from Japan, Sargassum
muticum may be washed up on the shore.
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Leathesia
Leathesia diformis is a hollow
brown sac-like seaweed often washed up on the beach
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Coral
Weed
Corallina officinalis - a red seaweed
whose fronds are impregnated with calcium carbonate absorbed from the sea water
giving it a 'coral' appearance.
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Sea Lettuce
Ulva lactuca - The Sea
Lettuce is a green seaweed commonly found in rock pools.
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Coelenterates - Sea Anemones
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These are among the most primitive of animals belonging to the
'Jellyfish' group. They catch their tiny prey using stinging cells on their
tentacles.
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Dahlia Anemone
Tealia felina lives in the rock
pools
below the water level. Identified
by the spots on its body.
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Beadlet Anemone
Actinia aquina lives in the rock pools,
but is sometimes
exposed at low tide when it withdraws its tentacles
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Snakelocks Anemone
Anemonia sulcata
also lives in the
rock pools. It has long brown tentacles.
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Annelids
- Bristle Worms: Some
are free swimming, but many live in tubes which are either cemented to
the rocks or buried in mud and sand. All sea anglers are familiar with
the lugworm which they often use as bait.
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Tube Worm
Pomatoceros trigueter lives in
a calcareous (chalky) tube cemented to the underside of rocks in rock pools.
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Tube Worm
Lanice conchilega
is a tube worm that lives in a tube made of mucus with attached sand
grains and a fringed end which sticks up out of the sand.
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Lug Worm
Arenicola marina
- The worm lives in a U-shaped burrow through which it wafts a current
of water. Its burrows are shown by the spiral 'worm casts' on the
surface of the mud or sand.
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Living Reefs:
An important component of the Cardigan Bay SAC is the presence of living
reefs made up of thousands of tube worms. These can be seen at Llanina
Point between Cei Bach and New Quay at low tide.
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Cei Bach Beach is in the background. The 'rocks' between
the pools are 'living reefs' of tube worms
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Tube Worm Sabellaria
alveolata .
This tube worms makes the sandy tubes that form huge
clusters on the rocks at Llanina Point.
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all photos © 2003 Rod
Attrill
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Cottages I
Activities I
The Area I Wildlife
I Beaches
I Disclaimer
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