Measurements by nieans of an oxygen electrode of the rate of oxygen consumption of a wide
variety of common intertidal invertebrates show that at least two rates of uptake can be
distinguished in the intact animal. First, there is a rapid rate of oxygen uptake corresponding
with activity and second there is a slower rate which corresponds with periods of quiescence
and which alternates with the fast rate. Intermediate rates correspond with intermediate rates
of overt activity. The maximal and minimal rates of oxygen uptake are affected differently by
temperature change. The fast rate corresponding to activity (“active metabolism”) increases
with temperature in approximate agreement with Arrhenius's law. The slow rate corresponding
to quiescence (“maintenance metabolism”) does not vary with temperature over much of the
range 7 to 22.5d̀ C. It is concluded that, contrary to common belief, the intertidal invertebrates
studied have a “basal metabolic rate” with a Q10 of approximately one over much of the normal
environmental temperature range and in this respect are well suited to life in a habitat where
rapid fluctuations in temperature occur.
Seaweeds
Seaweeds have mucilaginous outer layers which reduce evaporation during low tide when the
plant is susceptible to desiccation. During high tide seaweeds such as Bladderwrack Fucus
vesiculosus have gas-filled floats that keep the blades near the surface of the water, the blades
are the primary photosynthetic surface hence they are the part of the plant closest to the surface
of the water. The blades also create a canopy, restricting the amount of light reaching the plants
and animals beneath them, plants living here have adapted to cope with low light and use short
wavelengths of the light spectrum, such as red, for photosynthesis. During low tide the blades
collapse down onto the rocks as there is no water to support them and provide a moist hiding
place for crabs and other intertidal organisms. These are supported by the stipe which is sturdy
and flexible to withstand wave action. The stipe and the blades are anchored to the substrate by
a strong, root-like holdfast. As seaweed in the intertidal zone have to cope with the constant
wave action as well as desiccation at low tide they have cell walls composed of cellulose and gelforming polysaccharides, these provide a cushioning layer that protects the seaweed from the
waves whilst also reducing water loss during low tide.
Brown
Oarweed Laminaria digitata Upper sublittoral zone
 Kingdom: Chromista
 Phylum: Ochrophyta
 Class: Phaeophyceae
 Order: Laminariales
 Family: Laminariaceae
 Genus: Laminaria
 Scientific name: Laminaria digitata
Bladderwrack Fucus vesiculosus
 Kingdom: Chromista
 Phylum: Ochrophyta
 Class: Phaeophyceae
 Order: Fucales
 Family: Scarabaeoidea
 Genus: Fucus
 Scientific name: Fucus vesiculosus
Thongweed Himanthalia elongate
 Kingdom: Chromista
 Phylum: Ochrophyta
 Class: Phaeophyceae
 Order: Fucales
 Family: Scarabaeoidea
 Genus: Himanthalia
 Scientific name: - Himanthalia elongata
Red
Pepper Dulse Osmundea pinnatifida
 Kingdom: Plantae
 Phylum: Rhodophyta
 Class: Florideophyceae
 Order: Ceramiales
 Family: Pyraloidea
 Genus: Osmundea
 Botanical name: - Osmundea pinnatifida
Carragheen Chondrus crispus
 Kingdom: Plantae
 Phylum: Rhodophyta
 Class: Florideophyceae
 Order: Gigartinales
 Family: Gigartinaceae
 Genus: Chondrus
 Botanical name: - Chondrus crispus
Coral Weed Corallina officinalis
 Kingdom: Plantae
 Phylum: Rhodophyta
 Class: Florideophyceae
 Order: Corallinales
 Family: Corallinaceae
 Genus: Corallina
 Scientific name: Corallina officinalis
Coral Weed is rigid due to calcium in its structure.
Green
Sea lettuce Ulva lactuca
 Kingdom: Plantae
 Phylum: Chlorophyta
 Class: Ulvophyceae
 Order: Ulvales
 Family: Ulvaceae
 Genus: Ulva
 Botanical name: Ulva lactuca
Gut weed Ulva intestinalis
 Kingdom: Plantae
 Phylum: Chlorophyta
 Class: Ulvophyceae
 Order: Ulvales
 Family: Ulvaceae
 Genus: Ulva
 Botanical name: Ulva intestinalis
Cnidaria
Anemones are gelatinous, sedentary polyps bearing many tentacles; they have specialised cells
known as Cnidocytes, these, when triggered by passing prey, launch Nematocysts which are
long, barbed stinging cells that stun prey they can also provide protection from predators. Once
the prey is stunned the tentacles pass it to the mouth and it is digested in the gastrovascular
cavity, any indigestible material is ejected out through the mouth. The Anemone has developed
a Pedal Disk which attaches it to the substrate (usually rocks or boulders) preventing it from
being washed away as the tide rises and falls. To prevent desiccation at low tide the anemone is
able to secrete mucus to reduce water loss. Anemones are territorial, they will fight members of
their own and other species and drive them off to secure their own space, the loser will either
slowly move away or detach itself from the substrate and float away. There has been some
diversification in order to meet the challenges of different habitats.
Beadlet Anemone Actina equina- Upper shore
The Beadlet Anemone retracts its 192 tentacles when exposed to air, this prevents desiccation
as they are generally found on the upper shore. Acrorhagi are the blue beads situated on the
body wall. These have a high concentration of Nematocysts and can be used to show aggression
to neighbouring anemones by inflammation. This is used to fight for territory. Beadlet
Anemones reproduce via parthenogenesis- where an unfertilized egg develops into a new
individual. The young is budded and brooded internally in the body cavity

Kingdom: Animalia
 Phylum: Cnidaria
 Class: Anthozoa
 Order: Actiniaria
 Family: Actiniidae
 Genus: Actina
 Species: Actina equina
Strawberry Anemone Actinia fragacea- Lower shore
Like the Beadlet Anemone the Strawberry Anemone also has 192 retractable tentacles. However
it is larger.

Kingdom: Animalia
 Phylum: Cnidaria
 Class: Anthozoa
 Order: Actiniaria
 Family: Actiniidae
 Genus: Actinia
 Scientific name: Actinia fragacea
Snakelocks Anemone Anemonia viridis- Lower shore
Unlike the Beadlet and Strawberry Anemone, the Snakelocks Anemone has 200 tentacles which
it is not able to retract. This is probably due to where it is usually situated on the rocky shore.
Snakelocks Anemones are found on the lower shore in large, deep rockpools. They are very
rarely subjected to desiccation therefore they do not need to retract their tentacles.
In the tissue of the anemone is a symbiotic algae called Zooxanthellae. Snakelocks Anemone is
found in light rich pools as this algae needs light for photosynthesis: the anemone excretes
Carbon Dioxide which the algae then uses for photosynthesis, the algae excretes sugars and
oxygen which the anemone then uses in turn. If there is not enough light present the algae
numbers decline the anemone will turn to a muddy grey colour. Snakelocks Anemones can be
oviparous and lay eggs or reproduce by longitudinal fission where the anemone splits itself in
two, each being a clone of the other.

Kingdom: Animalia
 Phylum: Cnidaria
 Class: Anthozoa
 Order: Actiniaria
 Family: Actiniidae
 Genus: Anemonia
 Scientific name: Anemonia viridis
Echinoderms
The phylum Echinodermata includes the Sea Stars, Brittle Stars, Sea Urchins and Sea
Cucumbers, all species have an internal skeleton covered with spines and skin. They have
adapted a unique water vascular system that is a network of hydraulic canals, extending down
to the various adaptations of tube feet which are used for locomotion. They also have a
Madreporite, this is a “sieve plate” where water flows in and out of the water vascular system
into the surrounding water, this helps to maintain pressure in the water vascular system for the
tube feet.
Stars
Cushion Stars have a skeleton made up of calcareous ossicles that move with each other,
creating flexible joints. They have five legs arranged in a star shape; underneath they have
adapted hundreds of suction cups which they use for attachment to prevent the star from being
dislodged by wave action and to assist in capturing prey. They have the ability to sacrifice and
regenerate limbs; the limb is dropped and continues to move to distract the predator. The Sea
Star has a central disk which consists of a nerve ring and chords radiating into all 5 of its arms, if
a Sea Star loses one leg and 1/8th of its central disk a new individual can be regenerated from
the fragment. When the cushion star has captured prey it everts its stomach out of the body
cavity and engulfs the prey, it then secretes digestive enzymes to break down and absorb the
prey. Cushion Stars are protandrous hermaphroditic, and so the male reproductive organs
mature before the female reproductive organs.
Cushion Star Asterina gibbosa- Lower/middle shore
Small and young individuals are all males, as they grow and become older they develop into
females. Eggs are deposited in a preferred location, no parental investment is given. Several
males congregate around 1 female.

Kingdom: Animalia
 Phylum: Echinodermata
 Class: Stelleroidea
 Order: Spinulosida
 Family: Asterinidae
 Genus: Asterina
 Scientific name: Asterina gibbosa
Small Cushion Star Asterina phylactica- Middle shore
Fully developed male during first year then becomes a simultaneous hermaphrodite with fully
developed male and female sexual gonads. Although self fertilisation is possible they usually
congregate into groups to ensure some cross fertilisation. The eggs are brooded until hatched.

Kingdom: Animalia
 Phylum: Echinodermata
 Class: Stelleroidea
 Order: Spinulosida
 Family: Asterinidae
 Genus: Asterina
 Scientific name: Asterina phylactica
Brittle Star Ophiothrix fragilis Lower shore
Brittle Stars have ossicles embedded beneath their skin for support and ease of movement. The
arms of a Brittle Star are very fragile, hence the name. Mucus is secreted onto the arms of the
Brittle star, the arms are then put into the water column and plankton is trapped. Trapped
particles are collected together and passed down the arm into the Brittle Stars mouth. They also
scavenge decaying matter. Brittle Stars are dioecious i.e separate sexed. Approximately one
week after spawning planktonic larvae are expelled into the water column, these larvae undergo
metamorphosis into young Brittle Stars and eventually settle in the sediment.
Brittle Stars have been seen to congregate in fairly large groups where the water current is fast.
This social aggregation provides mutual support allowing each individual to prevent being
swept away whilst still enabling them to extend some of their legs into the water column and so
allowing feeding to take place. In severe conditions they link arms and flatten themselves to the
substrate to avoid being washed away. This would explain why a small group of Brittle Stars
were found on the lower shore and single individuals on the upper shore.

Kingdom: Animalia
 Phylum: Echinodermata
 Class: Ophiuroidea
 Order: Ophiurida
 Family: Curculionoidea
 Genus: Ophiothrix
 Scientific name: Ophiothrix fragilis
Green Sea Urchin Psammechinus miliaris
Sea Urchins are spherical shaped, dioecious Echinoderms. They have a skeleton known as the
test, this, like the Sea Stars is made from calcareous ossicles but here they are fused together.
The structure used for feeding is found on the base of the Urchin, in contact with the substrate
this is known as Aristotle’s lantern. In the centre of Aristotle’s lantern there are 5 teeth that
continuously grow and are worn down as they graze algae off rocks and other surfaces. The
majority of the outer surface is covered in tube feet and spines these are used for locomotion
and protection against predators. Sea Urchins have been seen to shelter under seaweed and
empty shells to shield themselves from the effects of sunlight in shallow water. Some species of
Urchins have adapted to have a symbiotic relationship with small shrimp and various species of
fish.

Kingdom: Animalia
 Phylum: Echinodermata
 Class: Echinoidea
 Order: Echinoida
 Family: Curculionoidea
 Genus: Psammechinus
 Scientific name: Psammechinus miliaris
Arthropods
Seventy five percent of the animal kingdom belongs to the phylum Arthropoda although this is
split into the classes chelicerates the insects, and the crustaceans. The crustaceans are the
largest class of marine arthropods and include crabs, lobsters, shrimps, hermit crabs, krill,
copepods and numerous other types of organism. Crustaceans can in turn be split into two main
groups, the malacostraceans (the larger e.g. crabs, shrimp, and lobsters) and the
entomostracans (smaller species e.g. barnacles, fairy shrimp, water fleas, and copepods).
Crustaceans are in the main dioecious with separate male and female individuals although the
actual ways which they reproduce vary widely, some crustaceans have a larval stage whereas
others hatch young that look like tiny adults.
Crabs
Crabs have ten limbs, most of which have adaptations, the first pair of appendages have evolved
into antennae and the next three or more have developed into mouthparts including the
mandibles. The first still obvious pair of limbs have evolved into pincers which are used for
grabbing food and fighting with other individuals. The remaining pairs of limbs are used for
walking and anchoring. Most crabs are active predators and scavengers, consuming a wide
variety of other animals
The cuticle of a crab is hardened by calcium carbonate, creating a hard exoskeleton. To grow the
crab needs to moult, this means the old exoskeleton is periodically shed and discarded,
revealing a larger, soft, exoskeleton. This is a vulnerable time for the crab until the new
exoskeleton hardens and predation is to be avoided at all costs until the hardening process has
finished. Moulting is also a chance for the crab to regenerate limbs which may have been lost
due to predation or through the act of autotomy, where an appendage is voluntarily sacrificed if
it is trapped.
Just before the breeding season the male holds onto the female until she moults, copulation
takes place, and then female then digs a pit in which to lay her eggs. She then attaches them to
her abdomen and back legs and she is then classed as ‘berried’. The berried females carry their
eggs around for a number of months until they hatch. Females have the ability to store sperm to
be used to fertilise eggs at a later date.
Common Shore Crab Carcinus maenas
The common shore crab varies vastly in colouration and is characterized by 5 spikes on the
carapace either side of the eyes. The legs are relatively short in the Common Shore crab and
they have been proven to be easily swept away by waves, this would indicate they are adapted
more for a shore environment. The Common Shore crab is very adaptable and can tolerate a
varied range of salinity and temperature. Instead of extracting oxygen out of the water, air is
bubbled through the gills at low tide.

Kingdom: Animalia

Phylum: Arthropoda
 Class: Malacostraca
 Order: Decapoda
 Family: Portunoidea
 Genus: Carcinus
 Scientific name: Carcinus maenas
Edible/Brown crab- Cancer pagurus- Lower shore
The Edible crab is one of the largest crabs found on the shore. It is easily identified due to the
reddish brown colouring, oval shaped carapace and ‘piecrust’ edge. The pincers are tipped black
and toothed.

Kingdom: Animalia

Phylum: Arthropoda

Class: Malacostraca

Order: Decapoda

Family: Cancroidea

Genus: Cancer

Scientific name: Cancer pagurus

Velvet Swimming Crab- Macropipus puber -Lower shore
Velvet Swimming crabs have fine hairs on the carapace. They have an aggressive temperament;
this is signalled by the red eyes. The legs have adapted to become flattened for enhanced
swimming.

Kingdom: Animalia
 Phylum: Arthropoda
 Class: Malacostraca
 Order: Decapoda
 Family: Portunoidea
 Genus: Macropipus
 Scientific name: Macropipus puber
Broad Clawed Porcelain Crab- Porcellana platycheles The Broad Clawed Porcelain Crab is a muddy brown, hairy crab. They are not true crabs and are
relatives of the Squat Lobster. They are distinguished from crabs by the number of apparent
walking legs present, 3 instead of 4. The crab traps mud amongst the hairs on its carapace to
camouflage itself against its surroundings. It is dorsoventrally flattened which makes them very
difficult to dislodge from the rock or hiding place. Broad Clawed Porcelain Crabs cannot swim
upwards from the substrate, but individuals that have just moulted their old exoskeleton can.
This is due to loss of heavy minerals, increasing buoyancy. This allows the crab to escape
predators on the substrate. Broad Clawed Porcelain Crabs are not active predators but instead
they are suspension feeders- combing plankton using adapted structures on the mouth. The
broad claws are used for protection against predators and scavenging detritus.

Kingdom: Animalia
 Phylum: Arthropoda
 Class: Malacostraca
 Order: Decapoda
 Family: Porcellanidae
 Genus: Porcellana
 Scientific name: Porcellana platycheles
Common Hermit Crab- Eupagurus bernhardus
Hermit Crabs are not true crabs and are closely related to Lobsters, they are soft bodied and
twisted, allowing them to inhabit shells from whelks, top shells and other Gastropods which it
replaces as it grows. The tail of the hermit crab grips the inside of the shell with a hook,
anchoring the body in-ORIGINAL APPENDAGES?. They are omnivorous scavengers, eating
anything they can find, they are also capable of filtering particles from the water. As the shell the
crab inhabits is heavy two pairs of legs are used to grip it, leaving two pairs for locomotion. The
right claw is larger than the left and is used to close off the shells aperture when the Hermit
Crab retreats inside. The female carries the eggs which hatch into pelagic larvae.

Kingdom: Animalia
 Phylum: Arthropoda
 Class: Malacostraca
 Order: Decapoda
 Family: Paguridae
 Genus: Pagurus
 Scientific Name: Pargurus bernhardus
Barnacles
Barnacles are Arthropods which permanently cement themselves to rocks they are conical in
shape and the cuticle is hardened into a protective shell which is comprised of a number of
plates with an opening or aperture. Barnacles are able to close off the aperture at low tide to
prevent desiccation by closing the operculum; this is made up of two plates which close
together tightly. They breathe through gills in the mantle wall. Like other arthropods Barnacles
need to moult in order to grow although this is dependent on temperature and food availability.
Barnacles feed by extending six pairs of feather like tentacles called cirri out through the
aperture, in still water they wave them around in order to capture plankton whilst in stronger
currents they are simply held still to conserve energy. When food is caught the cirri then retract
to pass food into the mouth
Barnacles are hermaphrodites although they usually take on the roll of either male or female,
the females will incubate their eggs in two sacs over winter later releasing planktonic larvae
into the water column.
Acorn Barnacle Elminius modestus All levels, more commonly mid-shore
http://species-identification.org/species.php?species_group=crustacea&id=92
http://www.seaonscreen.org/vleet/content/eng/sacculina-carcini.htm
http://www.pznow.co.uk/marine/barnacles.html
http://www.oceaninn.com/the-nature-preserve/crustaceans/

Kingdom: Animalia
 Phylum: Arthropoda
 Class: Maxillopoda
 Order: Sessilia
 Family: Balanoidea
 Genus: Elminius
 Scientific name: Elminius modestus
Parasitic barnacle Sacculina carcini
The life of a Sacculina would make a good alien horror film. It begins life as a swimming larva. As soon as the female larva
smells a crab, she goes after it and looks for a soft spot in one of its joints. Via this soft spot, she spouts several cells into
the body, which form a slug, discarding the majority of her body (a kind of molting). This slug crawls down deep in the
underside of the crab, where it starts to grow. She develops multiple tendrils which start to move throughout the crab's
body, sometimes even surrounding the eyes. She forms a kind of knob (see photo) in the underside, situated precisely
where the crab would normally carry its eggs. The knob slowly chips away as the crab moves around in the water, revealing
an opening. Unless a male comes around, the female will remain at this stage the rest of her life. However, should a male
Sacculina land on the crab and find the miniscule opening, then he too injects part of himself into the knob, molting away
the rest of his body. The male now searches for the necessary parts of the female, where it fuses and starts producing
sperm. He remains here the rest of his life. Actually, the female has capacity for two males. The two males continually
fertilize her eggs, producing thousands of larvae every few weeks.
http://www.theseashore.org.uk/theseashore/SpeciesPages/Saccullina.html
http://www.seaonscreen.org/vleet/content/eng/sacculina-carcini.htm
http://www.marinespecies.org/aphia.php?p=taxdetails&id=134805
http://www.pznow.co.uk/marine/barnacles.html
Sacculina carcini is a species of parasitic barnacle that mainly infects the common shore crab.
When the parasitic barnacle finds a host crab it bores through a weak point in the exoskeleton
and creates a web of fine internal threads in which it feeds on the host’s internal fluids.
Makes crab insterile
Fem^
Femal bores lots of holes in ekoskel to allow entry for male barnacle. She has provision for two
males. Male fertilises females eggs which form a large smooth egg mass on the underside of the
crab,
The male planktonic larva penetrates the outer bag and parasitises the female, forming a
kind of large testis in her body. The effect on the host crab depends on its sex. Male hosts are
made sterile. Female hosts behave like an individual carrying eggs and migrates into deeper
water.
interferes with the growth processes of the crab, male crabs changing body form and behaviour to
that of female over the following moults. The female form is needed by the barnacle. Ironically the
barnacle’s produces a sponge like reproductive mass in the same place where the crab would have
its own eggs, the crab caring for them as if it was their own.
To prevent removal from the crab during moulting of the shell, it later interferes with the crab’s natural
cycle by stopping the crab moulting. An indicator of the parasite are crabs that have barnacles or
worm encrustations on their shell. This is a good indicator that the crab has been parasitized. Healthy
crabs regularly moult, not providing enough time for barnacles or worms to become established.
http://www.theseashore.org.uk/theseashore/SpeciesPages/Saccullina.html
http://species-identification.org/species.php?species_group=crustacea&id=92
http://www.seaonscreen.org/vleet/content/eng/sacculina-carcini.htm
http://www.pznow.co.uk/marine/barnacles.html
http://www.oceaninn.com/the-nature-preserve/crustaceans/
Molluscs
The phylum Mollusca includes the classes Bivalvia (Mussels and Clams etc), Gastropoda
(Topshells, Whelks, Limpets) and Polyplacophora (Chitons).
Molluscs have a mantle covering the soft body, in the majority of molluscs the mantle secretes
calcium carbonate forming the hard external shell, however, some have completely lost their
hard shells through evolution, these are the nudibranchs. Depending on the species of Mollusc,
the mantle cavity holds the kidneys, anus, reproductive organs or gills. The majority of species
in the phylum Mollusca have a muscular foot.
Cephlapods
The Cephalopods, literally translated as ‘head foot’, are all marine animals and this class
includes some of the most advanced of the invertebrates. They are intelligent predators and
although identifiable as molluscs they have become greatly modified. Cephalopods have a large
head with obvious eyes and a central mouth with tentacles surrounding it, the number of
tentacles present vary by species. The shell has become severely modified and takes various
forms e.g. the Nautilus which only occupies the outer part of its chambered shell using the inner
part as a buoyancy aid, in the Squid and Cuttlefish the shell has become flattened and is used
internally as a stiffener (see sample box no((think))), whilst the Octopus has disposed of it all
together. The lack of an external shell means that the cephalopods are much more flexible
making them capable of moving through the water at speed, when alarmed water is forcibly
expelled from the siphon thereby jet propelling the animal away from danger; they also produce
a dark ink to deter prey. All cephalopods are dioecious and fertilisation is internal.
Gastropods
This class includes the snails, slugs, whelks and periwinkles and are the largest group of
molluscs; they have either a single shell or indeed no shell at all. They tend to be more mobile
than the bivalves and are common on land as well as in salt and fresh water.
Limpets
All Limpets begin life as males, either true males or protandric males; this means that at around
two to three years old the protandric males undergo a sex change to females.
Limpets attach themselves to the rocks using a large muscular foot which is also used for
movement. The mantle surrounds the foot and lines the shell; around the mantle are specialised
gill structures.
Limpets graze on algae growing on the rocks, leaving a mucus trail as they go, the head and two
tentacles can be seen as the Limpet grazes. Limpets possess a feeding structure known as a
Radula. The Radula rasps at the rock, grazing algae. It continuously grows as the rough surface
of the rocks erodes it away. As the tide goes out they follow their own trail back to their ‘home’
spot. Eventually the limpet leaves an indentation or ‘scar’ on the rock; this allows a perfect fit
and reduces evaporation during low tide.
The Limpets release eggs or sperm into the water column where fertilisation occurs, the larvae
settle in crevices and eventually migrate to more exposed habitats.
The shape of the shell allows a large surface area to be in contact with the rock, increasing the
hold the foot has.
Limpets are a valuable species to the ecosystem, if Limpets are taken out of a location algae
grows uncontrollably, coating the rocks and restricting light for other plants and animals such
as Snakelocks Anemone.
Common Limpet Patella vulgata
The Common Limpet’s shell varies with where on the shore it is found, taller shells with less of a
water current are found on the higher shore while lower shells that are in contact with waves
and faster currents are found on the lower shore.

Kingdom: Animalia
 Phylum: Mollusca
 Class: Gastropoda
 Order: Archaeogastropoda
 Family: Patellidae
 Genus: Patella
 Scientific Name: Patella vulgata
Black Footed Limpet Patella depressa
Unlike the Common Limpet, the Black Footed Limpet has little variance on how steep the shell is
as it mainly inhabits the lower shore where water currents are faster. The Black Footed Limpet
has a striped shell with dark banding where as the Common Limpet is generally all one colour.

Kingdom: Animalia
 Phylum: Mollusca
 Class: Gastropoda
 Order: Archaeogastropoda
 Family: Patellidae
 Genus: Patella
 Scientific name: Patella depressa
Periwinkles
Periwinkles are marine snails that inhabit all zones of the rocky shore. They feed on various
seaweeds, rasping at the surface with their radula.
HerbivorousPeriwinkles are a very adaptive group, the four species between them have manage to settle most of
the zones. The small periwinkle living in the splash zone on the extreme upper shore; the rough
winkle periwinkle the upper shore to the middle shore; while the flat periwinkle and edible periwinkle
the middle shore to the lower shore.
The zones where the species live has affected their development. the rough periwinkle that live higher
up on the beach and hence are uncovered by the tide for most of the time, have evolved the ability to
breath in air. The other two species living further down the shore have not evolved this ability.
Common Periwinkle Littorina littorea Middle to lower shore
Horny operculum on the foot to cover the opening of the shell- this prevents drying out
periwinkle grazes on detritus and microorganisms. It also feeds on green seaweeds such as sea lettuce- radula
The sexes are separate (individuals are either male or female), and fertilisation occurs internally after copulation
Egg laying is timed to coincide with the spring tide; the eggs are laid in the sea in gelatinous capsules that usually contain
around three eggs
free-swimming ‘veliger’ larvae hatch after a few days. After 6 weeks spent in the ocean, the larvae settle on the shore.

Kingdom: Animalia
 Phylum: Mollusca
 Class: Gastropoda
 Order: Neotaenioglossa

Family: Armadilloidea
 Genus: Littorina
 Scientific name: Littorina littorea
Rough Periwinkle Littorina saxatilis
Upper to middle shore, breaths air

Kingdom: Animalia
 Phylum: Mollusca
 Class: Gastropoda
 Order: Neotaenioglossa
 Family: Vespoidea
 Genus: Littorina
 Scientific name: Littorina saxatilis
Common Whelk Buccinum undatum Widespread- upper and lower shore


Whelks have a large muscular foot for holding down prey.
Kingdom: Animalia
 Phylum: Mollusca
 Class: Gastropoda
 Order: Sorbeoconcha
 Family: Buccinidae
 Genus: Buccinum
 Scientific name: Buccinum undatum
Top shells
They eat microscopic algae, sporelings and almost certainly ingest organic debris in the
process
secretes a shell around its body to protect it from the biotic and abiotic hazards of its
environment. The shell is impervious to gasses and liquids and surprisingly resistant to
crushing, http://www.field-studies-council.org/fieldstudies/documents/vol10.1_265.pdf
Topshells
Have a circular operculum (the horny plate which seals off the aperture when the snail retracts
into its shell).
Have a nacreous (mother-of-pearl) layer on the inside of the shell - most obvious on the inside
of the outer lip - which may become visible on the outside of older shells as the coloured layer is
eroded away.
Have shells marked with a complicated pattern composed of blotches and/or zigzag lines. There
is a pure white form of one species, but none has a pattern of simple stripes.
Usually have an umbilicus.
Winkles
Have an ear-shaped or sub-oval operculum.
Lack a nacreous layer on the inside of the shell.
The inside of the outer lip is dark or the same colour as the outer surface.
Have shells which are uniformly coloured or which bear broad or narrow bands that run round
the spiral at right angles to the lip.
Never have an umbilicus.
Grey Top Shell Gibbula cineraria
Grey Topshell lacks the tolerance to environmental stress like other Gibbula species and is
found lower down the shore. Grey Topshells are intolerant of high temperatures, hence they
are only found low down the shore

Kingdom: Animalia
 Phylum: Mollusca
 Class: Gastropoda
 Order: Archaeogastropoda
 Family: Trochidae
 Genus: Gibbula
 Scientific name: Gibbula cineraria
Purple Top Shell Gibbula umbilicalis
Purple Topshell (Gibbula umbilicalis) is probably the most widespread species and is around
15 mm tall. This topshell species has a hollow spiral through the centre of the shell (the hole
can be seen when turned over). A horny plate, the operculum, closes across the shell opening
reducing water loss at low tide. In topshells as a group, the operculum is round. In
Periwinkles it is tear-drop shaped (elongated).
Bivalves
This class includes clams, mussels, scallops and oysters, the name bivalve comes from the two
valves into which their shell is divided, they have large powerful adductor muscles which can
clamp the shell closed when danger presents itself. In bivalves the foot is laterally compressed.
They are mainly sedentary filter feeders able to move slowly or in some species the adductor
muscles are opened and closed at speed propelling the animal out of dangerous situations.
Bivalves
Common Mussel Mytilus edulis
Mussels are primarily sedentary, they are filter feeders filtering plankton from the water as it
passes in through the inhalant siphon and out the exhalant siphon, as part of this process small
particles of inedible detritus are trapped inside the mussel, these eventually settle down into
the substrate, for this reason mussels have an important part in clearing the water. During low
tide the mussel uses the adductor muscles to close its shell; this provides protection from
predation by many terrestrial predators and also prevents desiccation during low tide as the
mussel traps water inside the shell during this period.
Mussels attach themselves to rock and seaweed holdfasts by forming viscous byssus threads
secreted from their byssus pit, these threads gradually harden in the water, the mussel then
forms an attachment plate on the end of the byssal thread, once attached the mussel changes
position and creates another thread, it will continue in this way until it has several threads and
is anchored securely. In order to withstand wave action mussels aggregate into dense
communities or beds, binding themselves to the substrate and to each other.
Mussels are dioecious and fertilisation takes place in the surrounding water where the eggs
hatch into free swimming larvae.

Kingdom: Animalia
 Phylum: Mollusca
 Class: Bivalvia
 Order: Mytiloida
 Family: Mytilidae
 Genus: Mytilus
 Scientific name: Mytilus edulis
Grey Chiton Lepidochitona cinerea
Chitons are a species of Mollusc armoured with eight overlapping calcareous plates. A large
muscular foot is used in the same way as a Limpet, to keep the Chiton firmly attached to the
substrate and to allow movement. The overlapping plates, plus the fact that they have a strong
longitudinal muscle, enables them to roll up into a tight protective ball if they are dislodged
from the rock. Chitons have evolved to have no mantle cavity, this lack of a mantle cavity means
it has no true gills, to combat this problem the Chiton has a channel all around the animal
between the mantle and the foot containing several gill like structures. In this groove there is
also a subradular chemical sensory organ that protrudes under the cavity and is held against the
substrate to detect food, in this case algae. If alga is present the Chiton will graze it off the rock
using the radula, a tooth like appendage. Chitons have aesthetes on their dorsal plates; this is an
organ with the ability to sense light thus enabling the Chiton to detect if a predator is
approaching and to tightly anchor itself to the substrate in defence. Chitons are dioecious i.e.
either male or female and fertilisation takes place externally and larvae are produced.

Kingdom: Animalia
 Phylum: Mollusca
 Class: Polyplacophora
 Order: Chitonida
 Family: Tonicellidae
 Genus: Lepidochitona
 Scientific name: Lepidochitona cinerea
Rockpool Prawn Palaemon elegans
The shrimp is opaque allowing it to be highly camouflaged in the water.
Abdominal section can flex rapidly for propulsion as it is mainly muscle
Two pairs of antennae allow the shrimp to find food by "tasting” the water
The exoskeleton is shed periodically in order to grow.
The two prawn species Palaemon adspersus Rathke and P. elegans Rathke differ in their
distribution patterns in estuaries: P. adspersus occurs at lower salinities and also extends
further into the Baltic than P. elegans. Yet, at low salinities adult survival does not differ
between the two species. Reproductive success was, however, substantially reduced in P.
elegans at low salinity, but not in P. adspersus. Berried P. elegans females from the Swedish
west coast hatched significantly fewer clutches at 10%‰ than did P. adspersus females from
the same locality. Furthermore, larval survival in P. elegans was significantly lower at 5 and
7.5‰ than in P. adspersus. At higher salinities (10 and 24.5‰) no interspecific differences in
larval survival were found, except in one experiment where P. elegans larvae had a lower
mortality. It is concluded that the different estuarine distributions of the two palaemonid prawn
species result from these interspecific differences in reproductive success at low salinity
The first two pairs of walking legs bear claws (chela) and have yellow and red banding.
Scavenger These are fertilised internally & then released as planktotrophic zoea larvae
http://www.pznow.co.uk/marine/decopoda.html
http://www.fao.org/docrep/005/AC740T/AC740T32.htm
http://www.int-res.com/articles/meps/20/m020p127.pdf

Kingdom: Animalia
 Phylum: Arthropoda
 Class: Malacostraca
 Order: Decapoda
 Family: Palaemonoidea
 Genus: Palaemon
Scientific name: Palaemon elegans
Annelids
Keelworm - Pomatoceros triqueter
When the tide goes out of danger is near the keelworm retreats into the calcerous tube uses
operculum or seal the tube off
Keelworms can be found encrusted on rocks, shells and on the exoskeletons of some species of
____ in the form of a calcareous shell.
Keelworms feed on plankton by spreading out the branchial filaments
oper
The calcareous tube of Pomatoceros triqueter is 3.5 mm wide and up to 25 mm long. It is white,
smooth and irregularly curved with a single, median ridge that ends in a projection over the
anterior opening.
Males are cream in colour whilst females are bright pink/orange in colour. Eats Plankton and
detritus never leaves its tube. Occasionally the posterior end of the tube becomes blocked by a
calcareous plate with holes in. Respiration and excretion take place using cilia action to set up
currents, bringing water in and down the length of the tube and flushing it back out the same way.
Respiration occurs through the surface of the body and the branchial crown.
Feeding takes place by spreading apart its branchial filaments to expose a central groove. Using
cilia action, it induces a current and transports food particles towards it mouth. If particles are too
large or too numerous, the tip of a filament bends over and removes it. No sorting of food particles
takes place.

Kingdom: Animalia
 Phylum: Annelida
 Class: Polychaeta
 Order: Canalipalpata
 Family: Serpulidae
 Genus: Pomatoceros
 Scientific name: Pomatoceros triqueter
Green Leaf Worm Eulalia viridis- Middle to Lower shore
The Green Leaf Worm is easily identifiable, the colour as the name suggests, varies through
different shades of green. The Green Leaf Worm scavenges on dead or dying animals such as
mussels and barnacles and has been seen to insert it’s proboscis between the aperture plates of
a barnacle and consume it. They are dioecious i.e. male or female. After egg fertilisation green
egg masses can be seen attached to seaweed on the shore, this is to prevent it from being
washed out into the ocean when hatched the larvae are planktonic.

Kingdom: Animalia
 Phylum: Annelida
 Class: Polychaeta
 Order: Phyllodocida
 Family: Phyllodocidae
 Genus: Eulalia
 Scientific name: Eulalia viridis

Scale Worm 1 Alentia gelatinosa
This Scale Worm has a jelly like appearance when it is out of water, in water it can be a fairly
fast swimmer and has been described to swim in a slinky manner. 18 pairs of soft
semitransparent shells give it the jelly like appearance. During low tide it can be found
underneath rocks or among algae, keeping moist and prevent desiccation
The elytra of scaleworms help to direct the flow of oxygenated water along the body surface
when the worm is wedged into spaces where oxygen is limited (adapted from Morris et al
1980).
Halosydna are scavengers and detritus feeders. Their feeding apparatus consists of an eversible
proboscis armed with powerful jaws at its inverted tip.
Eggs of a gravid (egg-bearing) female H. brevisetosa are held within the body cavity and are
released for external fertilization.

Kingdom: Animalia
 Phylum: Annelida
 Class: Polychaeta
 Order: Aciculata
 Family: Alucitoidea
 Genus: Alentia

Scientific name: Alentia gelatinosa
Chordates
Cornish Sucker/ Shore Clingfish Lepadogaster purpurea
The Shore Clingfish also known as the Cornish Sucker are dorsally flattened with a duck billed
snout this allows them to move quickly through the rockpools and seaweed, their markings
reflect their surroundings and have a blue spot behind each eye. The pelvic fins of the Cornish
Sucker have modified and have fused together into a sucker, enabling it to attach to the
substrate and large smooth pebbles. They have a lateral line which detects vibrations and
changes in water pressure to aid the clingfish to locate prey and detect how close they are.
Cornish Suckers are dioecious, after the male has fertilised the female she lays eggs in a single
layer fixed underneath rocks and shells, the eggs are then guarded by the parents until the
larvae hatch.

Kingdom: Animalia
 Phylum: Chordata
 Class: Osteichthyes
 Order: Gobiesociformes
 Family: Gobiesocidae
 Genus: Lepadogaster
 Scientific name: Lepadogaster purpurea
Worm Pipefish Nerophis lumbriciformis
The Worm Pipefish is a long, thin snake like fish with a dorsal fin running nearly the entire
length of the body . Being long and thin enables the pipefish to use its prehensile tail to coil
around seaweed holdfasts to prevent the water current from washing them away as it recedes.
They come in a variety of colour which enables them to camouflage in with the seaweed,
reducing the chances of predation. The male pipefish fertilises the female, during the
fertilisation the eggs are transferred and adhered to the male’s abdomen which he then broods.
The female mates with more than one male.
The Worm Pipefish is a long, thin snake like fish with a dorsal fin running nearly the entire
length of the body . Being long and thin enables the pipefish to use its prehensile tail to coil
around seaweed holdfasts to prevent the water current from washing them away as it recedes.
They come in a variety of colours enabling them to camouflage themselves in the seaweed and
so reducing the chances of predation. Pipefish hunt by sight and have a unique ability to form a
vacuum inside their mouths to automatically suck in their prey which are usually tiny
crustaceans.
The female will mate with more than one male and will fight off other females for a mate. After a
courtship of elaborate displays the male pipefish fertilises the female while they are coiled
together, during this fertilisation the eggs are transferred to the male’s brood pouch in his
abdomen where they will hatch, he then broods them until they are released as free swimming
tiny versions of the adult. In times of reduced food availability the male can absorb some of the
eggs to ensure that he and at least a few of the eggs survive, males have also been known to eat
their young as they are released, regarding them as food.

Kingdom: Animalia
 Phylum: Chordata
 Class: Actinopterygii
 Order: Syngnathiformes
 Family: Syngnathidae
 Genus: Nerophis
 Scientific name: Nerophis lumbriciformis
‘Reproductive Ecology and Operational Sex Ratio of Worm Pipefish (Nerophis lumbriciformis)
in Irish Waters’
Common Goby Pomatoschistus microps
the top of the head, nape and throat are scaleless.
May lay eggs under a shell. Male guards the eggs
The acute toxicity of linear alkylbenzene sulfonate (LAS) on the common goby (Pomatoschistus
microps), an estuarine fish, was established during a 96-h static exposure. The median lethal
concentration was 2.6 ± 0.49 mg LAS/L (mean ± 95% confidence limit). The acute behavioral
responses to LAS at different concentrations were excess mucus secretion and apathy at 1.0
mg/L; air gulping, distension of the mouth and opercula, change in pigmentation, and erratic
swimming at 2.0 to 3.0 mg/L; and loss of balance and reactivity at ≤4.0 mg/L. The frequency of
operculum opening increased with increasing LAS concentrations and appeared at 4.0 mg/L,
with a significant doubling in relation to the frequency observed in control fish (p = 0.025). The
physiological responses by P. microps after prolonged exposure to sublethal and
environmentally realistic concentrations of LAS (0.05-1.0 mg/L) were observed under
semistatic conditions in the laboratory. Ingestion, respiration, and growth were also measured
during 28 d of exposure. A significant decrease in growth and respiration was found at 0.1 mg
LAS/L (p = 0.049 and 0.033, respectively), but ingestion was not affected. The effect
concentrations for growth and respiration represent the lowest-observed-effect concentrations,
which are both lower than values previously reported for fish. Gross conversion efficiency was
affected negatively at 1.0 mg LAS/L (p = 0.001). Pomatoschistus microps is recommended as a
suitable and relevant test organism for ecotoxicological experiments.

Kingdom: Animalia

Phylum: Chordata
 Class: Actinopterygii
 Order: Perciformes
 Family: Gobiidae
 Genus: Pomatoschistus
 Scientific name: Pomatoschistus microps
Thornback Ray Raja clavata

Kingdom: Animalia
 Phylum: Chordata
 Class: Chondrichthyes
 Order: Rajiformes
 Family: Rajidae
 Genus: Raja
 Scientific name: Raja clavata
Lesser spotted catshark Scyliorhinus canicula

Kingdom: Animalia
 Phylum: Chordata
 Class: Chondrichthyes
 Order: Carcharhiniformes
 Family: Scyliorhinidae
 Genus: Scyliorhinus
 Scientific name: Scyliorhinus canicula
Star Ascidian Botryllus schlosseri
The Star Ascidian is a colonial sea squirt commonly found in areas of good water currents;
several individuals or Zooids form small groups which make up the colony. Each squirt has an
inhalant siphon to allow a flow of water into it; this water flow is controlled by the use of cilia so
each Zooid can trap food particles as they flow through the mucus coated pharynx. These food
particles are then passed to the stomach where they are digested. The water then flows out of
an exhalant siphon shared by the group. The Star Ascidian derives its name from the shape of
the group formed i.e. a star shape, each “arm” of the star is an individual, with the shared
exhalant siphon located in the centre. If the sea squirts are disturbed by predators a jet of water
is forced out via the exhalant siphon to deter them.
The Star Ascidian is a hermaphrodite capable of asexual reproduction, also known as buddingthis is usually done to increase the size of the colony until it is large enough to reproduce
sexually. Sexual reproduction involves each individual releasing male gametes into the
surrounding water, they are then sucked into the inhalant siphons of its neighbours, the eggs
are then fertilised inside. The eggs develop internally and are eventually released as freeswimming larvae through the exhalant siphon; this tadpole like larva has a nerve chord and a
notochord meaning they are chordates at this stage, this is lost when they later settle to form a
colony.

Kingdom: Animalia
 Phylum: Chordata
 Class: Ascidiacea
 Order: Pleurogona
 Family: Styelidae
 Genus: Botryllus
 Scientific name: Botryllus schlosseri
References
littoral and Benthic Investigations on the West Coast of Ireland: XXII. The Biology of a
Population of Shore Clingfish Lepadogaster lepadogaster (Bonnaterre, 1788) at Inishbofin, Co.
Galway