BIOLOGY & STATUS OF

ROCKYSHORE
ORGANISMS
COURSE NO.:
AEM-216

SUBMITTED
TO
Dr. S. K. ROUT SUBMITTED BY
DEPT. OF AEM SUSMITA
MUKHERJEE
B.F.Sc 2ND YR 1ST
SEM
FS- 31/13
 WHAT IS ROCKY
SHORE?
 A rocky shore is an intertidal area that consists of
solid rocks.
 It is often a biologically rich environment and can
include many different habitat types like steep rocky
cliffs, platforms, rock pools and boulder fields.
 Because of the continuously action of the tides, it is
characterized by erosional features. Together with
the wind, sunlight and other physical factors it
creates a complex environment.
 Organisms that live in this area experience daily
fluctuations in their environment. For this reason,
they must be able to tolerate extreme changes in
temperature, salinity, moisture and wave action to
survive
 ZONATION
 Rocky Shore can be divided into 3
Zones.
1.Supratidal Zone
2.Intertidal Zone
3.Subtidal Zone
STATUS OF ROCKYSHORE
IN INDIA
•A consideration of the coastal regions of India gives us an
idea that a major part of the west coast is rocky.
•Silt covered rocky flats occurs in various places along the
Indian coast, particularly in the vicinity of the Gulf of
Cambay & in the Gulf of Kutch.
•One feature of these flats is the great area exposed during
the lowest lower water, when there is a vertical emersion of
about 12 meters & the shore is emersed to an extent of
about 152 meters.
•Steep rocky shores characterise much of the west coast of
India from Mumbai down to Kanyakumari & are interrupted
At frequent intervals by sandy areas.
•Around 588 kms of western coast & 75 kms of eastern
coast is rockyshore.
SUPRATIDAL ZONE
 Highest zone; extends above the highest point wet by the
tide. This upper region is called supratidal or splash zone.
 Organisms are exposed to the drying heat of the sun in
the summer and to extreme low temperatures in the
winter. Because of these severe conditions, only a few
resistant organisms live here.
 The organisms that live in this region are facing problems
like gas exchange, desiccation, temperature changes and
feeding.
 Common organisms are lichens. At the lower edge of the
splash zone, rough snails (periwinkles) graze on various
types of algae.
 T US
S TA
Y & S IN
LO G IS M
B IO G A N O N E
O R A L Z
OF A T ID
P R
SU
 LICHEN
 These black, orange, yellow or grey plants are
actually made up of a fungus and a microscopic
algae living together and sharing food and energy
to grow.
 Substrates and habitats : They are
abundant growing on bark, leaves, and hanging
from branches.
 They grow on bare rock, walls, gravestones,
roofs, exposed soil surfaces.
 They can even live inside solid rock, growing between the
grains, and in the soil as part of a biological soil crust in
arid habitats such as deserts.

 Vegetative reproduction- Many lichens reproduce

asexually, either by a piece breaking off and growing on its
own (vegetative reproduction) or through the dispersal of
diaspores containing a few algal cells surrounded by fungal
cells.

 Symbiotic relation - A lichen is a composite organism

that emerges from an algae or cyanobacteria living among
the filaments (hyphae) of a fungus in a mutually beneficial
(symbiotic) relationship.
PERIWINKLES
 The periwinkle or winkle, is a species of small edible sea snail, a
marine gastropod mollusc that has gills and an operculum, and is
classified within the family Littorinidae.

 Morphology - The shell is broadly ovate, thick, and sharply

pointed except when eroded. The shell contains six to seven
whorls with some fine threads and wrinkles.

 Habitat- Periwinkle is mainly found on rocky shores in the

higher and middle intertidal zone. It sometimes lives in small tide
pools.
 Feeding - Periwinkle is an omnivorous, grazing intertidal
gastropod, primarily on algae grazer, but it will feed on small
invertebrates such as barnacle larvae. They use their radulae to
scrape algae from rocks.

 Life cycle-
 Periwinkle is oviparous, reproducing annually with internal
fertilization of egg capsules that are then shed directly into the
sea, leading to a planktotrophic larval development time of four to
seven weeks.
 Females lay 10,000 to 100,000 eggs contained in a corneous
capsule from which larvae escape and settle to the bottom.
 This species can breed year round depending on the local
climate. It reaches maturity at 10 mm, and lives five to ten years.
INTERTIDAL ZONE

 The intertidal zone or littoral zone is the shoreward fringe of

the sea bed between the highest and lowest limit of the
tides.
 Because the intertidal zone is a transition zone between the
land and the sea, it causes heat stress, desiccation, oxygen
depletion and reduced opportunities for feeding.
 Higher-intertidal organisms are better adapted to
desiccation than lower-intertidal organisms, because they
encounter more hours of sun.
 The dominant species are Barnacles(upper part) Rockweed
(middle) Mussels (lower).
The Intertidal Zone Divided in 3
zones
 High tide zone or high intertidal zone- This region is
only flooded during high tides. Organisms that you can find here are
whelk, anemones, barnacles, chitons, crabs,isopods, mussels, star
fish , snails.
 Middle tide zone or mid-littoral zone. This is a
turbulent zone that is (un)covered twice a day. The zone extends
from the upper limit of the barnacles to the lower limit of large brown
algae.Common organisms are snails, sponges, sea stars, barnacles,
mussels, sea palms, crabs.
 Low intertidal zone or lower littoral zone. This region
is usually covered with water. It is only uncovered when the tide is
extremely low. The common organisms in this region are brown
seaweed, crabs, hydroids, mussels, sea cucumber, sea lettuce, sea
urchins, shrimps, snails, tube worms.
 &
G Y F
L O O IN
I O U S S
B AT SM L
T
S A N ID I A
G T
R ER E
O T N
I N ZO
 ORGANISMS
WHELK IN
HIGH TIDE ZONE
 Whelk is a common name that is applied to various kinds of
sea snail, many of which have historically been used, or are
still used, by humans for food.

 Habitat- Whelks can be found in the sandy or muddy

substrate of shallow embayments.

 Feeding - This whelk species feed primarily on marine

bivalves, ingesting their soft parts using its proboscis. It is an
elongated appendage from the head of an animal, either a
vertebrate or an invertebrate.
 SEA
ANEMONE
 Sea anemones are a group of water-dwelling, predatory
animals of the order Actinaria. An anemone is a single animal
with a sack-like body and tentacles around a single opening.
 Habitat- Most species inhabit tropical reefs, although there
are species adapted to relatively cold waters, intertidal reefs,
and sand/kelp environments.
 Feeding – It feeds on sea grass, small copepods etc.
 Symbiotic relationships- Many sea anemones form an
important facultative symbiotic relationship with certain
single-celled algae species that reside in the animals'
gastrodermal cells. A second symbiotic relationship is
formed between some sea anemones and clownfish.
 Life cycle-
 The sexes in sea anemones are separate in some
species, while other species, like the brooding
anemone,are protandric hermaphrodites.
 Both sexual and asexual reproduction can occur.
 In sexual reproduction, males release sperm to stimulate
females to release eggs, and fertilization occurs.
Anemones eject eggs and sperm through the mouth.
 The fertilized egg develops into a planula, which settles
and grows into a single polyp.
 Anemones can also reproduce asexually, by budding,
binary fission (the polyp separates into two halves), and
pedal laceration, in which small pieces of the pedal disc
break off and regenerate into small anemones.
 BARNACLES
 A barnacle is a type of arthropod constituting the
infraclass Cirripedia in the subphylum Crustacea.

 Feeding- Most barnacles are suspension feeders; they

dwell continually in their and reach into the water column
with modified legs. These feathery appendages beat
rhythmically to draw plankton and detritus into the shell
for consumption.

 Substrate - Barnacles are encrusters, attaching

themselves permanently to a hard substrate.
 Life cycle
 Barnacles have two distinct larval stages, the nauplius
and the cyprid, before developing into a mature adult.

 Nauplius - A fertilised egg hatches into a nauplius: a

one-eyed larva comprising a head and a telson, without a
thorax or abdomen. This undergoes 6 months of growth,
passing through five instars, before transforming into the
cyprid stage.

 Cyprid - The cyprid larva is the last larval stage before

adulthood. It is a non-feeding stage whose role is to find
a suitable place to settle, since the adults are sessile. It
attaches head-first using its antennules to a substrate,
and a secreted glycoproteinous substance.
 CHITON
 Chitons are small to large marine molluscs in the class
Polyplacophora, commonly known as sea cradles or "coat-of-
mail shells".

 Morphology - Chitons have a dorsal shell which is

composed of eight separate shell plates or valves. The plates
provide good protection for impacts from above. The shell
plates are surrounded by a structure known as a girdle.

 Habitat- Chitons live worldwide, in cold water, warm

water, and in the tropics..They live on hard surfaces, such as
on or under rocks, or in rock crevices.
 Feeding- Chitons are herbivorous grazers. They eat
algae, bryozoans, diatoms, and sometimes bacteria by
scraping the rocky substrate with their well-developed
radulae.
 Reproduction-
 Chitons have separate sexes, and fertilization is external.
 The male releases sperm into the water, while the female
releases eggs either individually, or in a long string.
 The egg hatches to release a free-swimming
trochophore larva.
 A segmented shell gland forms on one side of the larva,
and a foot forms on the opposite side. When the larva is
ready to become an adult, the body elongates, and the
shell gland secretes the plates of the shell.
 CRAB
 Crabs are decapod crustaceans of the infra order
Brachyura, which typically have a very short
projecting "tail” usually entirely hidden under the
thorax. They are generally covered with a thick
exoskeleton and have a single pair of claws.
 Feeding – They are nocturnal feeders feeding
mainly on bottom dwelling bivalve, crustaceans &
dead decayed animal matter.
 Habitat- They are found in burrows in the
intertidal & subtidal zones.
 Reproduction – Ovum
 Crabs attract a mate throughsperchemical (pheromones),
visual, acoustic or vibratorymmeans.
 The vast number of brachyuran crabs have Zoea internal
fertilisation and mate belly-to-belly. For(differe
many aquatic
species, mating takes place just after the nt female has
Adult
moulted and is still soft. stages
 Females can store the sperm for a long time of before using
zoea)
it to fertilise their eggs.
 When fertilisation has taken place, the eggs are released
onto the female's abdomen, below the tail flap, secured
with a sticky material. In this location they are protected
Juve
during embryonic development.
Megal
nile opa
 ISOPODS
 Isopoda is an order (group) of crustaceans that includes
woodlice, sea slaters and their relatives.

 Morphology- They have two pairs of antennae, seven pairs

of jointed limbs on the thorax, and five pairs of branching
appendages on the abdomen that are used in respiration.

 Feeding- Isopods are detritivores and browsers, carnivores

(including predators and scavengers), parasites, and filter
feeders, and may occupy one or more of these feeding niches.
Some exhibit coprophagia and will also consume their own fecal
pellets.
 Reproduction –
 Males have a pair of penises, which may be fused in
some species.
 The sperm is transferred to the female by the
modified second pleopod which receives it from the
penis and which is then inserted into a female
gonopore.
 The sperm is stored in a special receptacle, a
swelling on the oviduct close to the gonopore.
 Fertilisation only takes place when the eggs are
shed soon after a moult, at which time a connection
is established between the semen receptacle and
the oviduct.
 MUSSEL

 Morphology- Mussel is the common name used for

members of several families of clams or bivalve molluscs

 Feeding- Marine mussels are filter feeders; they feed

on plankton and other microscopic sea creatures which
are free-floating in seawater.

 Habitat- Marine mussels are abundant in the low and

mid intertidal zone in temperate seas globally. Other
species of marine mussel live in tropical intertidal areas.
 Reproduction - Marine mussels are gonochoristic,
with separate male and female individuals.
 Sperm is released by the male directly into the water
and enters the female via the incurrent siphon.
 After fertilization, the eggs develop into a larval stage
called a glochidium (plural glochidia), which
temporarily parasitize fish, attaching themselves to the
fish's fins or gills.
 Prior to their release, the glochidia grow in the gills of
the female mussel where they are constantly flushed
with oxygen-rich water.
 They grow, break free from the host, and drop to the
bottom of the water to begin an independent life.
STAR FISH
 Morphology-The starfish (commonly as a sea star) is generally
found with 5 arms that are attached to a central disc. This central
disc is the activity center of the starfish and also contains the
mouth of the starfish.

 Feeding- The starfish feeds on oysters and clams, the 2

stomachs of the starfish helping with the digestion of complex
organisms.

 Vascular system- The water vascular system of the starfish

has many projections called tube feet on the ventral face of the
starfish's arms which function in movement and aid with feeding.

 Habitat- Starfish can be found in the oceans all around the

world.
 Reproduction- Starfish can change their gender
when it is convenient to them.
 The female starfish is capable is releasing over 2 million
eggs at any one time.
 The eggs released by the female starfish are then
fertilized by the male starfish and the fertilized eggs
develop into larvae which are able to swim about.
 Starfish larvae swim for about three weeks before settling
and beginning metamorphosis into the more common
appearance of the starfish.
 The starfish has the incredible ability to regenerate
itself into a new starfish, with a single lost arm
attached to a portion of the central starfish body
disc!
 SNAIL

 Feeding- In order to break down their food, most use

radula. The radula rips the food into small pieces for the
hungry snail.
Snails are generally herbivores, primarily eating
vegetation such as leaves, stems and flowers.

 Reproduction- Despite being hermaphrodites (meaning

that they possess both male and female reproductive organs),
snails have to mate with another snail in order to fertilise their
eggs.
Up to a month after mating, the snails lays small white
eggs into a burrow in the ground or on a covered leaf, which
hatch after a couple of weeks. Baby snails can take up to two
years to reach full adulthood.
 ORGANISMS
SPONGES OF MIDDLE
INTERTIDAL ZONE
Feeding- Sponges
 The dominant
Morphology- The bodyare omnivorous
of the animals
sponge is that obtain
made up of
species in the middle
their nutrition from the food particles in the water. Sponges
a jelly-like
primarily
substance
intertidal zone
eat bacteria,
that
are is– supported
phytoplanktonsnails, by a thin
and bitsbarnacles,
out of the water.
layer of cells onstar
sponges, eitherfish,
side.mussels,crabs etc.
The body of- Sponges
Reproduction the sponge contain thousands
are hermaphrodites, which of
poresthat
means which
theyallow water
have both to and
male keep flowing
female through it.
reproductive
organs. Fertilisation occurs inside many sponges, and
sometimes externally when sperm are released into the water.
The tiny sponge larvae are able to move through the water
and eventually settle on the sea floor as they get bigger, and
begin to move very little.
 HERMIT
CRAB
Development
Habitat-
The young
Mostdevelop in stages,
species are aquatic with theinfirst
and live varying
depths
two (theofnauplius
salt water,
andfrom shallow reefs
protozoea) and
occurring
shorelines
inside to deep sea bottoms. Most hermit crabs
the egg.
are nocturnal.
Most hermit crab larvae hatch at the third
stage, the zoea.
Feeding- Hermitstage,
In this larval crabs are
the omnivorous detritivore
crab has several long
that opportunistically
spines, a long, narrow scavenges
abdomen, forand
carrion and
large
which can
fringed also filter feed when necessary.
antennae.
Several zoeal moults are followed by the final
larval stage, the megalopa
 0RGANISMS OF LOW
BROWN SEAWEED
INTERTIDAL ZONE
•Sea
Brown seaweed,
weed which chitons, crabs,
forms greenish-brown, hydroids,
brainlike growths, is
mussels,
common sea and
in late spring cucumbers, sea urchins,
summer on patches of rock.
shrimps, tubeworms etc. are mostly
•Hedophyllum sessile, a very coarse brown kelp, resembling a
availablecabbage
loose-headed in thisbecause
area.of the way its several broadlobes
spread from the holdfast.

•Is an important source of food for herbivorous snails and chitons.

In quiet water, the lobes usually have a blistered appearance;
where the water is rough, they tend to be smooth.
 I
HYDROIDS
HYD R O
D
 Hydroids are a life stage for most animals of the class
Hydrozoa, small predators related to jellyfish.
 The majority of hydroids are colonial. The original polyp
is anchored to a solid substrate and forms a bud which
remains attached to its parent.
 The polyps are connected by epidermis which surrounds
a gastrovascular cavity.
 The epidermis secretes a chitinous skeleton which
supports the stem and in some hydroids, the skeleton
extends into a cup shape surrounding the polyp.
SEA CUCUMBER

 Habitat- Sea cucumbers can be found in great

numbers on the deep seafloor, where they often make
up the majority of the animal biomass

 Diet- they are generally scavengers, feeding on

debris in the benthic zone of the ocean. Some have a
commensal relationship with deep-sea angler
 Defensive systems- Sea cucumber ejects
sticky filaments from the anus in self-defense.

 Reproduction –
 Most sea cucumbers reproduce by releasing sperm and
ova into the ocean water.
 Sea cucumbers are typically dioecious, but some
species are protandric.
 The reproductive system consists of a single gonad,
consisting of a cluster of tubules emptying into a single
duct that opens on the upper surface of the animal,
close to the tentacles.
 SEA URCHIN
 Morphology- Sea urchins have a round
shaped body and with long spines that come
off it. Sea urchins have five paired rows of tiny
tube feet which are found amongst the spines.
The feet of the sea urchin have suckers.
 Feeding- Sea urchins are omnivorous
animals and therefore eat both plant and
animal matter. The sea urchin mainly feeds on
algae on the coral and rocks, along with
decomposing matter such as dead fish,
mussels, sponges and barnacles.
 Habitat- Sea urchins are commonly found
along the rocky ocean floor in both shallow and
deeper water and are also commonly found
inhabiting coral reefs.
 Breeding-
 It spawns during the spring, and the female sea
urchin releases millions of tiny, jelly-coated eggs
into the water that are then fertilised by the sperm
of the male sea urchin.
 The sea urchin young will not become large
enough to retreat from the plankton and down to
the ocean floor until they are between 2 and 5
years old.
 SHRIMP

 Shrimp are marine crustaceans that are found on

the bottom of the water in nearly every
environment around the world. Shrimps are
generally tiny in size.

 Habitat- The shrimp lives on the river beds and

ocean floors around the world, filtering sand and
particles in the water.
 Feeding- Shrimps are omnivorous animals and
therefore ingest and variety of both plant and animal
species. Shrimp mainly feed on algae and other plant
particles along with tiny fish and plankton in the water.

 Reproduction- The female shrimp can lay up to

a million eggs at once that only take a couple of weeks
to hatch. The tiny shrimp become part of the plankton
in the water until they are big enough to big hunting in
groups for larger food particles.
 TUBE WORM
 Morphology- A tube worm is any worm-like sessile
invertebrate that anchors its tail to an underwater surface
and secretes around its body a mineral tube, into which it
can withdraw its entire body.

 Reproduction-To reproduce, females release lipid-

rich eggs into the surrounding water so they start to float
upwards. The males then unleash sperm bundles that
swim to meet the eggs. After the eggs have hatched, the
larvae swim down to attach themselves to the rock.
 Energy and nutrient source-
 With sunlight not available directly as a form of
energy, the tubeworms rely on bacteria in their
habitat to oxidize hydrogen sulfide, using
dissolved oxygen in the water as electron
acceptor.
 This reaction provides the energy needed for
chemosynthesis.
 For this reason, tube worms are partially
dependent on sunlight as an energy source, since
they use free oxygen, which has been liberated by
photosynthesis in water layers far above.
 SUBTIDAL ZONE
 The subtidal zone or sublittoral zone is the region below
the intertidal zone and is continuously covered by water.
 Temperature, water pressure and sunlight radiation
remain nearly constant.
 Organisms do not dry out as often as organisms higher
on the beach. They grow much faster and are better in
competition for the same niche. More essential nutrients
are acquired from the water and they are buffered from
extreme changes in temperature.
 Most common species are sea squirt, sea star, sea
anemones, sea urchins, sea slug etc.
 BI
OR OLO
SU GA GY
B T N I S OF
ID M
AL S
I
ZO N
NE
 SEA SQUIRT

 Morphology- Their bodies are made of one solid

structure (rather than having a skeleton), which is
protected by a membrane just a few cells thick. Sea
squirts are normally cylindrical in shape, but can also be
round or even bell-shaped.

 Feeding- Sea squirts are filter feeders. They primarily

feed on the plankton and nutrients in the water along with
the algae that grows on them.
 Reproduction –
 Sea squirts have both male and female
reproductive organs making self-fertilisation
possible but unlikely.
 The sea squirts release their eggs and sperm into
the water which become fertilised and part of the
plankton.
 The sea squirt larvae hatches out of the eggs and
makes it way down to the ocean floor in search for
somewhere to anchor itself.
 SEA
SLUG
 Feeding- The sea slug is a herbivorous animals
and feeds on plankton and decaying matter on the
ocean floor, along with grazing on the rocks and coral
reefs for algae.

 Protection- Some species of sea slug are able to

protect themselves from danger by wrapping their
tentacles around potential predators, so that the
predator is unable to harm them. This only applies
however to the species of sea slug that actually have
tentacles, others are completely defenceless.
 Reproduction-
 The sea slug is a hermaphrodite, meaning that
the sea slug has both male and female
reproductive organs.
 Sea slugs release eggs into the water in ribbon-
like sticky clusters which can contain
thousands of eggs but usually much less.
 The eggs are fertilized and the sea slug larvae
(the baby sea slugs) soon develop and become
bigger, after hatching from their sticky eggs.
 THREATS TO THE
BIOLOGICAL
COMMUNITIES
 The rapid rate of erosion frequently exposes bedrock
and prevents the development of stable, ‘mature’
communities & destabilizes the community.
 The aftermath of oil spills demonstrates the
vulnerability of rocky shore communities to acute
impacts.
 Chemical dispersants and mechanical cleaning can do
even more damage to the community than the oil itself.
 Localised disturbance to rocky shore communities will
be caused by dumping or building on the shore.
 CONCLUSI
ON
The rocky shore is a habitat that
contains wide range of microhabitats and
ecological niches for different creatures.
This is mainly due to the effects of the
tides that rise and fall twice each day.
But due to pollution & natural
factors organisms are likely to be extinct
in a short span of time.
Thus we should all be aware of
the essentiality of this particular diverse
ecology and show interest in conserving
the rockshores and its inhabitant
organisms.
REFERENCE
S

 MARINE BIOLOGY-
Nybakken
 www.google.com
 www.wikipedis.com
 PDF - Life on Rocky
shores by Eugene N.
Kozlof