This document provides information about coral reef ecosystems. It begins with an introduction describing coral reefs as beautiful, ancient ecosystems that are threatened. It then discusses the anatomy and types of corals, where reefs grow, the symbiotic relationship between corals and algae, and threats such as human impacts and climate change. The document contains detailed sections on coral reef formation, ecology, importance, threats, and conservation efforts.

1. 1 | College of Fisheries, (JAU), Veraval
AN ASSIGNMENT
ON
Coral Reef Ecosystem
Course Name: Library and Information Services (PGS 501)
Submitted to,
Sh. C. H Shah
Senior Librarian Technician
Junagadh Agricultural University,
Junagadh, (Gujrat)
Submitted By,
Name: Krishna
Reg. No. 2030316005
M.F.Sc. 1st
Year
College of fisheries,
(J.A.U.), Veraval
COLLEGE OF FISHERIES
Junagadh Agricultural University
VERAVAL, GUJRAT 362265

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CONTENT
Sn. No. Particular Page No.
01. Introduction 03
02. What is coral 03-04
03. The coral body 04
04. Types of corals 04
I. Hard corals 04
II. Soft corals 05
05. Where do reefs grow 05
06. Corals and their plant partners 06
07. Food sources 06
08. Reproduction and growth 06-08
09. Coral reef formation 08
10. Types of reefs 08
I. Fringing reefs 08
II. Barrier reefs 08-09
III. Atolls 09
11. Ecological role of coral reefs 09
12. Importance of the coral reefs 09-10
13. Threats 11
I. Natural threats 11-12
II. Human-caused threats 12-15
14. Conservation of coral reefs 16-19
15. References 20

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INTRODUCTION
Coral reefs are one of the Earth’s most beautiful, ancient and complex ecosystems.
They play an essential role in sustaining life in the sea and serve as a source of food and
protection for human communities. But, coral reefs face an uncertain future. As a result of
growing human and environmental assaults, reefs are among the most threatened ecosystems
on earth. Ecological research provides information fundamental to understanding and
combating this trend.
Coral reefs are important marine ecosystems that are found in clear, shallow, tropical
waters around the world. They provide habitat for diverse communities of marine animals
and plants. Coral reefs consist of individual animals called coral polyps and their hard
exoskeletons. These small animals have soft, cylindrical bodies and a ring of tentacles
surrounding a mouth. The coral polyp is a member of the phylum Cnidaria, which also
includes anemones, jellies, sea whips, sea fans and siphonophores. All members of this
phylum, including coral, have tentacles which they use to catch prey. The tentacles are
covered with stinging cells called nematocysts, which can stun or even kill small animals
called zooplankton that drift too close to the coral. After the zooplankton have been stung, the
tentacles direct them toward the central mouth where they are digested.
Since coral polyps are soft-bodied animals, the bulk of a coral reef ecosystem comes
from the hard exoskeleton polyps create around themselves. The exoskeleton is composed of
calcium carbonate (CaCO3) found in sea water, and provides protection for polyps. Since
polyps occur in groups called colonies, coral reefs consist of a colony’s collective calcium
carbonate exoskeleton in addition to the living polyps.
All reef-building corals have algae called zooxanthellae living inside their tissues.
Through the process of photosynthesis, the algae convert carbon dioxide and water into
oxygen and carbohydrates. These carbohydrates provide nutrients for the coral polyp. The
polyp, in return, uses oxygen for respiration and provides carbon dioxide and shelter to the
zooxanthellae. Because these algae require light in order to perform photosynthesis, their
coral hosts are restricted to relatively shallow (30 meters), clear water. The algae account for
about half of the weight of the coral body, and algal pigments give the coral its color. Since
the algae play such a crucial role in coral survival, without it, coral reproduction comes to a
halt.
WHAT IS CORAL
Coral is an invertebrate (animal without a backbone) marine organism of the class
Anthozoa (phylum Cnidaria). Members of this class are characterized by a body that only
opens at one end, the mouth, and by skeletons, either internal or external, of a stone like,
horny, or leathery consistency. Some cnidarians, such as jellyfish, float through the water.
Others, such as sea anemones and corals, attach themselves to the reef. Basically, there are
two groups of corals: hermatypes, or hard corals that build reefs; and ahermatypes, or corals
(both soft and a few hard) that do not. The major difference between hard corals and soft
corals is that hard corals contain zooxanthellae (microscopic algae) within their tissue and the
soft corals do not. The term coral is also used to describe the skeletal remains of these

4. 4 | College of Fisheries, (JAU), Veraval
animals, particularly those of the hard corals which form a limestone base that becomes the
foundation of the reef. The Great Barrier Reef is the largest structure built by living
organisms on Earth, and it is the only living structure visible from outer space. Located along
the northeast coast of Australia, it measures 1,240 miles (2,000km) in length.
THE CORAL BODY
The body of a coral animal is called the polyp, a hollow sac-like structure that is
smaller than a common pencil eraser. At its free end is a mouth surrounded by tentacles, and
inside the body is a stomach. The sticky tentacles contain harpoon-like stinging structures,
called nematocysts that enable the polyp to gather food by paralyzing its passing prey. The
tentacles then deposit the food in the mouth where it passes down into the stomach. Nutrients
are absorbed from the food and any solid waste materials are passed back out through the
mouth. Within the stomach are long, tubular mesenterial filaments that the polyp extends to
defend itself from attack by other encroaching coral. In addition, the polyps of the hard corals
extract calcium carbonate from the sea water and use it to build a hard external limestone
skeleton beneath and around their base which secures the fragile polyp to a surface and serves
as its protection. Polyps have a mouth but they don’t have a head or any teeth for chewing
(Fig. 1).
Fig. 1. Coral body
TYPES OF CORALS
Hard Corals
Reef-building corals, which secrete a hard external limestone skeleton, are commonly
known as hard(stony) corals. They characteristically have tentacles in multiples of six and
can be found either individually or in colonies. These hard coral colonies exhibit three basic
growth forms: branching, massive, and plate.
Common types of hard corals are brain coral, mushroom coral, pillar coral, staghorn
coral, and plate (or table) coral. Water movement influences the shape of the corals. Where
strong waves hit the reef front, corals have thick branching, massive (boulder), or flattened
shapes. Where the water is calmer and deeper, the coral branches become more delicate and
some take on the shape of large thin plates to absorb a maximum amount of light for their
zooxanthellae. The mushroom coral is one of the few corals that does not grow in colonies.

5. 5 | College of Fisheries, (JAU), Veraval
Hard corals are the most widely distributed form of coral, occurring in all oceans from the
shallow tidal zone to depths of 20,000 feet (6,000m) (Fig. 2).
Soft Corals
Some types of corals secrete a flexible or soft skeleton. These are called octocorals, so
named for their characteristic eight tentacles. Octocorals include the soft coral, sea fan, black
coral, whip coral, and blue coral. Octocorals also grow in colonies on the reef, but do not
build reefs. They have branching, ribbon-like shapes and their soft internal skeleton allows
them to bend, wave, sway, and spread out in the water. Some of the soft corals produce toxic
compounds that make them unappetizing to predators. Soft corals thrive in strong currents
where they have access to lots of plankton. They also grow well in areas where hard corals
cannot grow, such as dark caves and overhangs.
Coral jewelry is made from harvesting soft coral, such as black coral and whip coral.
Killing coral to make jewelry and ornaments harms the reef (Fig. 3).
Fig. 2. Hard Coral Fig. 3. Soft Coral
WHERE DO REEFS GROW
Reef-building corals have very specific requirements for growth that limit their
distribution. The water must be clear, shallow and warm, with an optimum temperature of 24
degrees Celsius (75 degrees Farenheit). This temperature requirement limits coral growth to
tropical areas. Coral reefs are generally restricted to the eastern margins of continents where
warm water from the equator arrives with the currents. Consequently, coral reefs form off the
coast of Florida, but not off the coast of California, where the water is much colder.
However, not all water along tropical coastlines is suitable for coral reefs. Other
environmental factors, such as the amount of salt in the water, or salinity, can limit coral
growth. Corals require a salinity of at least 25 parts per thousand (ppt) and do best in full sea
water (35 ppt). Areas with high freshwater runoff, like the mouth of the Amazon River, lack
coral reefs because the salinity is too low.
Coral reefs exist where all the environmental factors necessary for coral growth
coincide. The major areas of reef development are in the Caribbean and the Indo-Pacific

6. 6 | College of Fisheries, (JAU), Veraval
regions. The largest reef in the world, the Great Barrier Reef, is located off the east coast of
Australia and spans 1,200 miles.
CORALS AND THEIR PLANT PARTNERS
Within the tissue of the polyp live many microscopic algae or plant cells called
zooxanthellae (also called endosymbionts). These algal cells have a symbiotic (mutually
beneficial) relationship with the coral. The algae provide the polyp with food through the
process of photosynthesis in which the plant cells use sunlight coming through the water to
convert the carbon dioxide and water in the polyp tissue into oxygen and carbohydrates. The
oxygen is used by the polyp for respiration and the carbohydrates are used for energy to build
its limestone skeleton. In return, the polyp provides the zooxanthellae with nutrients,
protection, a place to live, and carbon dioxide, a byproduct of respiration which is vital for
photosynthesis.
The color of the coral comes from the color of the zooxanthellae living in the polyp’s
tissue. This color can vary from white, yellow, brown, and olive to red, green, blue, and
purple. The color of the coral’s limestone skeleton without the zooxanthellae is white (Fig. 4).
Fig. 4. Corals and their plant partners
FOOD SOURCES
In addition to getting food internally from the zooxanthellae, some corals eat plankton.
Plankton are creatures, both plant and animal, that move passively through the water at the
mercy of wind and ocean currents. Most plankton are too small for you to see unaided. The
plant plankton are called phytoplankton and the animal plankton are called zooplankton.
They acquire their nutrients and energy from a different, distant ecosystem. It is estimated
that as much as 60% of the plankton on the reef are eaten by the coral polyps as they drift by.
Most corals feed only at night, extending their tentacles when they are less likely to be
preyed upon. During the day, the tentacles are withdrawn into the skeleton for protection.
Since corals are animals, those that eat only plants (phytoplankton) are called herbivores, and
those that eat only animals (zooplankton and small fishes) are called carnivores.
REPRODUCTION AND GROWTH

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Coral polyps reproduce both sexually (with a partner) and asexually (by themselves).
Sexual reproduction occurs when the corals spawn, releasing eggs and sperm into the water.
The sperm then fertilizes the egg, creating a new individual called a planula or coral larva.
Spawning usually occurs in mass in order to give the eggs and sperm a better chance of
fertilizing themselves and surviving predators. Although most hard corals are hermaphroditic,
containing both male and female sex cells, they sometimes fertilize the sex cells of other
colonies thereby ensuring the coral’s ability to maintain genetic diversity and adapt to new
conditions.
Once produced, the planula, which already contains zooxanthellae from the parent,
floats up towards the light and drifts with the plankton from several hours up to several weeks.
Those that survive then swim back down, settle on a solid, rocky surface, and develop into
polyps. This is the only way in which the stationary hard corals can move to a new location.
This is also how corals develop on concrete blocks, shipwrecks, and oil drilling platforms.
Once a year in Australia, for a few nights following the full moon in spring (October
in
the southern hemisphere), more than 130 species of corals along the Great Barrier Reef
release millions and millions of eggs and sperm into the water at the same time. Reef
organisms, like anemones, sea cucumbers, and the crown-of-thorns starfish, also spawn at
this time. Asexual reproduction occurs by budding. The parent polyp clones itself by dividing
to form a new polyp which remains attached to the parent polyp’s tissue. A coral colony
develops by the constant addition of new buds (Fig. 5).
As the new polyps grow, the old polyps beneath them die, adding their limestone
skeletons to the foundation of the reef. In optimum conditions in nature, massive corals may
grow up to .8 inches (2cm) a year and branching corals up to 4 inches (10cm) a year. Because
of the corals’ slow growth, the creation of a reef can take hundreds of years. Coral colonies
may also be attached to others of the same or different species, forming large and complex
reef structures. Some of these colonies fight one another for more space and light by
extending their long arms or mesenterial filaments that the polyp uses to attack and kill the
other encroaching polyps. In the right conditions, new colonies can also grow from broken-
off fragments of the original colony. In this way, reefs are able to regrow themselves after
damage from storms, hurricanes, and cyclones.

8. 8 | College of Fisheries, (JAU), Veraval
Fig. 5. Reproduction of corals
In the 1970’s, it was discovered that the age of a coral could be determined in the
same way as a tree. By passing an X-ray through the coral, annual growth rings become
visible and can be counted. Some of the corals along the Great Barrier Reef are estimated to
be more than 800-1000 years old. This means that they first began growing around the time
that the Battle of Hastings was fought in England (1066AD) and the first Crusade left France
for Jerusalem (1096AD).
CORAL REEF FORMATION
Today’s coral reefs have accumulated during the last 10,000 years since the last
glacial periods of the Pleistocene epoch. As glacial ice melted and sea levels and
temperatures rose, present-day reefs began to form. Hard corals provide the main structural
framework. Other organisms, such as coralline algae and protozoans, bind and cement
everything together with sheet like growth that stabilizes the reef. Sand and sediments are
created by boring organisms, such as sponges and bivalves (i.e. clams, oysters); green
calcified algae (Halmedia) which has calcium carbonate plates that drop off; and, grazers,
such as parrotfish and sea urchins, which attack the coral for food, extracting nutrition from
the polyps, breaking down their limestone bases, and excreting the waste as sand. The
calcium carbonate from the sand, shells, and coral maintains the pH balance in the ocean
which in turn maintains life as we know it.
TYPES OF REEFS
Just as there are different types of corals, there are different types of coral reefs. The
three main types of reefs are fringing reefs, barrier reefs and atolls.
Fringing reefs

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Fringing reefs are coral reefs that grow in shallow waters. They closely border the
coastline or are separated from it by a narrow stretch of water. Many of the reefs round Sri
Lanka and Thailand are fringing reefs (Fig. 6).
Fig. 6. Fringing reef
Barrier reefs
Barrier reefs grow parallel to the coast, but are separated from land by a lagoon.
Theyare found sometimes many kilometresfrom shore (10–100km). Barrier reefs cangrow in
fairly deep water, because, often,the living coral builds upon remains ofcorals that grew in
the same area whensea level was lower, during the last iceage. The Great Barrier Reef of
Australiaextends about 2,010km parallel to theeast coast (Fig. 7).
Atolls
Atolls grow surrounding (or partly surrounding) an island which then sinks relative to
sea level (usually because volcanic activity forming the island stops), or was flooded as sea
level rose after the last ice age. Atolls surround (or partly surround) a central lagoon. The
Maldives consists of 26 atolls. Although these are the three main types of reefs, there are
many reefs that do not fit these models (Fig. 8).
Fig. 7. Barrier reef
Fig. 8. Atolls
ECOLOGICAL ROLE OF CORAL REEFS

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In addition to their high diversity, coral reefs are very productive marine communities.
They play a critical role as habitat and nursery grounds for 10% to 20% of the world’s
fisheries. They are intimately connected to other marine communities such as mangrove
forests, sea grass beds, and the open seas as water currents transport larvae, plants, animals,
nutrients, and organic materials. Coral reefs play a significant role in the development of
other ecosystems such as mangroves and wetlands and protect coastlines from wave and
storm damage and erosion. Life-saving medicines, such as anticoagulants, and anticancer
agents, such as prostaglandins, come from coral reefs.
The rocky framework of coral reefs is formed from the calcium carbonate deposited
mainly by calcareous algae and the stony corals, most of which are colonial animals
resembling tiny, interconnected sea anemones. Reef building corals contain symbiotic algae
in their tissues, enabling them to develop the large, massive, branching, or encrusting
carbonate skeletons that provide habitat and food resources for support of other reef
organisms, such as fish, lobsters, giant clams, and sea urchins to name but a few. Reefs
maintain a network of intimate ecological relationships and delicate food webs. Disruption of
coral reef communities can break up these ecological bonds. Under natural conditions, a
healthy coral reef can recover from natural disturbance such as hurricanes, within 10 to 20
years. But when subjected to chronic human-induced stress, recovery from even natural
disturbance may be impossible.
IMPORTANCE OF THE CORAL REEFS
Coral reefs are extremely productive ecosystems and provide humans with many services.
Provisioning Services
Coral reefs support human life and livelihoods and are important economically.
Nearly 500 million people depend - directly and indirectly – on coral reefs for their
livelihoods, food and other resources. Further, it is estimated that nearly 30 million of the
poorest human populations in the world depend entirely on coral reefs for their food. A km2
of well-managed coral reef can yield an average of 15 tonnes of fish and other seafood every
year.
Regulating Services
Very importantly, coral reefs protect the shoreline, providing a physical barrier – a
wall against tidal surges, extreme weather events, ocean currents, tides and winds. In doing so,
they prevent coastal erosion, flooding and loss of infrastructure. Because of this, they serve to
reduce huge costs involved with destruction and displacement due to extreme weather events.
The value of this protective service of coral reefs is estimated at 314 million USD in
Indonesia.
Supporting Services
The natural action of waves breaks pieces of calcified coral and these are washed up
onto beaches. Through the process of natural physical breakdown, these larger pieces are

11. 11 | College of Fisheries, (JAU), Veraval
broken into smaller and smaller pieces and eventually become part of the rubble, building
these beaches. Corals, therefore, contribute, in part, to the process of accretion - which is the
opposite of erosion.
Coral reefs are very diverse
Corals do not even cover 1% of the Earth’s surface, but they are extremely diverse. In
fact they are dubbed the rain forests of the sea because of this immense diversity. The nooks
and crannies formed within reefs by constant beating of waves provide shelter to many
species.
 They are the home (they provide shelter and nursery grounds) of 25% of marine fish.
 Thirty two out of the 34 described groups of organisms are found in coral reefs. (As a
comparison, only nine groups are found in tropical rain forests.).
 Coral reefs support a complex and interdependent community of photosynthesizing
organisms and animals. There is an incredible diversity of life on coral reefs such as
algae, corals (there may be as many as 750 species on one coral reef), sponges, marine
worms, echinoderms (sea stars and their relatives), molluscs (snails, mussels and their
relatives), crustaceans (crabs, shrimps and their relatives) and fish.
Coral reefs have high primary productivity
Zooxanthellae photosynthesize and produce their own food (like green plants do on
land) and corals benefit from this association. Because of the immense diversity of coral reefs,
there is a great deal of exchange of nutrients and primary productivity (food production) is
very high. Primary productivity of coral reefs is estimated at 5-10g C/m2/day. This
productivity is derived mainly from algae.
Cultural services
The beauty of coral reefs and their diversity are essential parts of many cultures in
different parts of the world. Because of their easy access, visiting coral reefs is an important
recreation for snorkelers, scuba divers, recreational fishermen and beach lovers.
 In Seychelles, tourism was estimated to have generated one fifth of GDP and over
60% of foreign exchange earnings in 1995.
 In the Maldives, ‘tourism contributes more than 60% of foreign exchange receipts,
over 90% of government tax revenue comes from import duties and tourism-
related taxes, and almost 40% of the workforce is employed in the industry’.
THREATS
Corals are highly sensitive to environmental conditions. They grow best in shallow,
clear water between 68˚F and 84˚F (20˚C and 29˚C) with normal oceanic salinity. Both
natural and human-caused (anthropogenic) disasters threaten coral reefs worldwide. In 1997,
the International Year of the Reef, it was recognized that corals around the world are
threatened:

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 In the Philippines, about 70% of the coral reefs have been degraded seriously and
only about 5% are thought to be in good condition;
 In Jakarta Bay, Indonesia, human activities have caused the average coral
coverage to diminish from 30% to 5% between 1985 and 1995;
 In Jamaica, where the coral coverage was 50% to 70%, overfishing has accounted
for a decline of coral coverage to just 5%;
 In the Florida Keys, coral diseases, massive algal blooms, and a precipitous drop
in water visibility on the world’s 3rd largest barrier reef reflects the damage from
agricultural runoff from Florida Bay and inadequate sewage treatment throughout
the Keys.
 Conservative estimates indicate that up to 10% of the Earth’s coral reefs are
already seriously degraded and a much larger percentage is threatened by the
impact of human activities;
 At the current rate of destruction, estimates indicate that 40% of the world’s reefs
could be destroyed by the year 2020.
While natural impacts such as hurricanes and population fluctuations of predators
play a role in the degradation of coral reefs, it is becoming increasingly clear that human
activities are having the most catastrophic effects on these fragile marine ecosystems. We all
know that human population growth is the single greatest threat to global environmental
health, but the problem has pointed significance for coastal regions. In 2025 three quarters of
the world’s population will be living within 50 miles of the world’s oceans, seas and lakes.
Natural Threats
Natural threats to coral reefs include sea level changes, hurricanes, cyclones,
abnormal weather patterns, fluctuations in seawater temperatures, heavy rains that dilute
salinity, extreme low tides that expose coral, disease, and predator population explosions,
such as crown-of-thorns sea stars. Reef scan sometimes recover from these seemingly
disastrous attacks if human-caused stresses do not impede their recuperation process.
Human-Caused Threats
The human impact on the world’s coral reefs are widespread and reaching
catastrophic proportions. Some scientists believe that the effect of coral reef destruction on
global biodiversity is of the same magnitude as that of the destruction of rainforests. Indeed,
coral reefs are often referred to as the “rainforests of the sea” because they are the most
biologically diverse marine ecosystem. The most destructive human impacts on coral reefs
include overharvesting of fish; destructive fishing practices (cyanide and dynamite fishing);
nutrients and pesticides draining onto the reefs from agricultural areas upstream; tourists who
unwittingly damage reefs, boat anchors dropped onto fragile corals; raw sewage from coastal
areas with insufficient treatment capacity; coral mining for construction materials;
sedimentation from deforestation, road construction and dams; and oil pollution from
shipping.
Overexploitation (Over-fishing)

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For food
A recent report states that ‘centuries of over-fishing by man have emptied the world’s
oceans of giant fish, whales and other large sea creatures, destroying coastal environments’.
 In Seychelles, tourism was estimated to have generated one fifth of GDP and
over 60% of foreign exchange earnings in 1995.
 In the Maldives, ‘tourism contributes more than 60% of foreign exchange
receipts, over 90% of government tax revenue comes from import duties and
tourism-related taxes, and almost 40% of the workforce is employed in the
industry’.
 In South Asia, 45% of 19,210 km2 of coral reefs have been destroyed, another
10% are critically threatened and 25% are threatened. Only 20% are at low
risk from human activities.
 In Southeast Asia, 38% of 91,700 km2 of coral reefs have been destroyed,
another 28% are critically threatened and 29% are threatened. Only 5% are at
low risk from human activities.
The human global population is expected to double in the next 50 years, and with it,
an ever increasing demand for life essentials such as food. Fish is the primary source of
protein for one fifth of the world’s population. The demand for fish has doubled in the last 50
years, and fish production would have to double again in the next 25 years to keep up with
the demand and population growth. Because coral reefs are within the reach of small boats,
they are especially vulnerable to over-fishing. Particular groups of coral reef fish such as
groupers, snappers and large wrasses have been overexploited. In Southeast Asia, the live fish
trade (both as food fish and as ornamentals) is estimated to be over a billion USD per year in
(mostly) illegal trade.
Irresponsible tourism
Tourism is essential for the economic development of many countries in the region.
For example, marine and coastal tourism is the largest industry in the Maldives and accounts
directly for 20% of GDP and its wider effects help produce 74% of national income; almost
40% of the workforce is employed in the industry. When carried out in a controlled and
sustainable manner, tourism can be a positive economic earner and should be an incentive for
countries to invest in managing coral reef ecosystems to continue attracting tourist revenue.
However, when managed poorly, tourism has both direct and indirect negative effects
on coral reefs. Snorkeling, diving and boating can cause direct physical damage to reefs,
while overexploitation of reef species as food, for aquaria and as curios for tourist markets
can threaten the survival of species. In some cases, bad tourism practices are not prevented.
For example, tourists are allowed to walk on reefs, causing physical damage to the reef
structure and stirring up sediment. Sometimes they even directly collect species off reefs.
Boats carrying tourists can damage reefs by dropping anchors directly onto reefs, disturbing
species and also causing marine pollution through excessive traffic.

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Indirectly, careless and irresponsible building of infrastructure directly onto reefs or
too close to beaches, river mouths and lagoons, results in increased sedimentation and leaves
the infrastructure vulnerable to damage from extreme weather events. Another indirect effect
of tourism is often the irresponsible disposal of sewage and solid waste. Two decades ago,
sewage and solid waste were mostly disposed directly into the sea but the current situation
has improved greatly.
Global Warming and the Greenhouse Effect
Greenhouse gases (carbon dioxide, methane, nitrous oxide and chlorofluoro-carbons)
are accumulating in the atmosphere, trapping the heat from the sun and causing the Earth’s
atmosphere to become abnormally warm. These gases are increasing as people burn more
fossil fuels for energy and cut down carbon-dioxide absorbing forests. The resulting increase
in sea temperatures, sea levels, and violent storms negatively affect corals. The weakened
coral then becomes more susceptible to disease. One of these effects, coral bleaching, results
when the coral is stressed, as when the water temperature becomes too warm for the coral
polyps to survive. When the polyps die, the coral loses its color and becomes white.
Harmful Fishing Practices
Coral reefs provide habitat for marine life, such as fish, turtles, octopus, bivalves
(mussels, clams), gastropods (snails, conchs), spiny lobster, shrimp, echinoderms (sea
cucumbers, urchins). These are sources of food and income for many coastal people, as well
as large commercial fishing operators. Around the world, more and more fisheries are
collapsing (species of fish are disappearing from many areas) due to damaging fishing
techniques and overfishing (more fish being harvested than the area can reproduce). In many
places, traditional fishing methods have been replaced with super-efficient modern
technologies, often with damaging long term effects. The introduction of motorized boats and
SCUBA gear, such as masks and fins, has increased the catch, often to unsustainable levels.
Biodegradable traps and nets woven from vegetable fiber or coconut fronds have been
replaced with non-biodegradable nylon, metal and wire. When lost they often become
dangerous: entangling and injuring or killing marine life (Figure 3-4), breaking corals, or
continuing to catch fish that will never be collected.
Cyanide Poisoning
Cyanide poison is used by fishers in Indonesia, the Philippines, and other island
nations to stun fish, making them easier to catch. Chlorine bleach and quinaldine are used in
the United States. Hunting for food or aquarium fish, the fishers shoot the chemical solutions
at reef fish or into coral enclaves where they live. The poisonous residue kills coral,
invertebrates, and other fish. Fishers in the Pacific and Southeast Asia often blast reefs with
dynamite or other explosives that rupture fishes’ air bladders so they can scoop them up as
they float to the surface. The explosions destroy reef formations, kill non-target fish (by-
catch), and often kill or maim the fishers themselves. Some fishers also use ‘Muro-Ami’,
which is the name of the net that fish are driven into when hundreds of boys pound on the
coral and wave white plastic streamers. Again, this technique damages the coral and results in
huge quantities of by-catch.

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Mariculture
Mariculture, the farming of marine plants and animals, is becoming more popular in
the tropics, often in response to the loss of wild stocks. Giant clams, fish, conch, seaweed and
shrimp are among the many farmed species. Unfortunately, while mariculture provides a
means of employment and reduces pressure on overexploited stocks, it can have a negative
impact on the reef. In many areas, entire mangrove forests have been bulldozed to make
shallow ponds for these farms, eliminating juvenile fish nurseries and habitat for marine birds
and animals. In addition, these farms siphon already short fresh water supplies, poison the
water with chemicals and antibiotics, and cause a decrease in wild fish populations.
Ultimately, the coastal people are left with little protein source since they are unable to afford
the mariculture product.
Damage from Boats
In areas that are popular with recreational, diving or fishing boats, the reef is subject
to damage from accidents and carelessness. Anchors tossed on coral break the fragile animals
(Figure 3-5), and the chains drag a swath of destruction around them. Boats and ships that run
aground on the reef can destroy hundreds of corals in an instant. Propellers churn up
sediments that smother the reef. Boat bilges and toilets are discharged, dumping an overload
of algae-causing nutrients into the water. Some cruise ships and recreational boats have been
documented dumping their trash overboard, despite laws against ocean dumping.
Damage from Divers
Although recreational divers are often the greatest advocates for protection of coral
reefs, careless diving can present a hazard to the ecosystem. Popular dive spots often attract
more visitors than is healthy for the area. Lack of mooring buoys can result in damage from
anchors. Unscrupulous dive charters may use food to lure fish toward their customers,
disrupting their normal feeding and behavior patterns. Divers and snorkelers who take
souvenirs, touch coral, let their fins and other equipment bash into it, or even kick up excess
sediments contribute to the demise of the very reef they came to enjoy.
Coral Mining
Coral mining is a problem in countries with few resources for construction. Iron bars
are used to dismantle entire sections of reef to build roads, walls, homes and office buildings.
Pollution
After it rains, storm water runoff carries trash, oils, chemicals, and other undesirables
from the land into the sea. Fertilizer, pesticides, and herbicides from agriculture also wash out
of fields into streams and into the ocean. Chemicals, such as chlorine-based cleaning
solutions, PCB’s and DDT, heavy metals, and minerals from mining and other industrial
pollution are known to be poisonous to marine animals.
Deforestation and development

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Deforestation and development can damage coral reefs offshore, smothered by
loosened soils washed by rain into rivers and out to sea. Insufficiently treated or raw sewage
introduces excess nutrients on the reef, covering corals with algae. Warm water discharges
from power plants cause corals to bleach. Large sections of reef off Guam and Taiwan have
been destroyed by this thermal pollution. Corals are vulnerable to oil pollution caused by
spills, leaks in tanks or pipelines, ships flushing their tanks and bilges, offshore oil
exploration and land-based sources, such as refineries and gas stations. Trash from fishing
vessels, cruise ships, recreational boaters, ocean dumping and beach visitors inflicts damage
on beaches, reefs, and marine animals. Some turtles and seabirds often make the deadly
mistake of eating plastic bags and debris because it resembles one of their favorite foods,
jellyfish. Every year many marine animals and fish are entangled in nylon fishing nets, six-
pack rings and other garbage.
Radioactive pollution
Radioactive pollution, including nuclear bombs, accidents and leaks at nuclear power
plants, and nuclear testing, whether atmospheric, underground or underwater, all are known
to kill a wide range of reef life.
Dredging
Dredging to clear channels for shipping, marinas, and ports, or to mine coral rock or
sand causes excess silt to contaminate the water. Corals can be damaged by artificially
created channels, as they trigger changes in water circulation, tidal flow, and water levels.
Coral Harvesting
Coral is also harvested to make jewelry, gift store curios (Figure 3-7), coffee table
knick-knacks, and aquarium habitat. Under optimum conditions, many corals take 37 years to
regenerate.

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CONSERVATION OF CORAL REEFS
Given that 20% of the world’s coral reefs have already been destroyed much has to be
done in the future for the conservation of coral reefs.
Establishment of marine protected areas
One of the key mechanisms of protecting coral reefs is the establishment of Marine
Protected Areas (MPAs). Although there are many types of MPAs, in all MPAs, marine areas
are set aside from unrestricted human activities. Where restriction is highest, MPAs are set
aside as ‘no-take’ areas where extraction of all marine life is prohibited; even research,
education and recreation is restricted. Some MPAs are established and managed specifically
for a purpose (for example, for recreation, for the preservation of a historical site or as a
refuge for a particular species to breed). Multiple-use MPAs are zoned to allow for complete
restriction of harvest in some areas, restricted use in others and managed use in yet others.
Although more and more MPAs are being established now worldwide, the ratio
between MPA and terrestrial protected areas still remains low at 1:7. Less than 1% of the
world’s oceans are protected.
However, a major problem with MPAs is that they are often only parks on paper and a
majority of MPAs fail to meet their management objectives: in 1995, only 31% (1306) MPAs
were found to have met their management objectives. Even though MPAs may be gazetted
legally, enforcement of relevant laws (zoning, prohibiting certain activities) is often poor.
Prevention of over-harvesting through legislation
Many species are protected under general species protection laws across the region.
Most of this protection is afforded to marine vertebrates, but some countries - such as India
and Sri Lanka - have laws protecting several species of coral, molluscs and echinoderms.
Monitoring
Monitoring of coral reefs is essential for the development of effective management
strategies. It is only through monitoring that trends and patterns of use and the health of reefs
can be assessed.
Worldwide, there are several organisations that monitor the status of coral reefs. The
Global Coral Reef Monitoring Network (GCRMN) coordinates efforts to improve the
management of coral reefs through knowledge sharing and capacity building, and works
closely with Reef Check and Reef Base. The latter is a global database of coral reef related
information. After the 1998 coral bleaching event, and with the ongoing threat of coral
degradation as a consequence of other human activities, Coastal Ocean Research and
Development in the Indian Ocean (CORDIO) was commenced in 1999. CORDIO funds and
supports scientists and institutions in the Indian Ocean Region, to ensure that the status of
coral reefs in the region is monitored, focussing both on the ecological and socio-economic
effects of coral reef degradation. Many other organisations partner these major players to
provide an annual status report of coral reefs across the world.
Building awareness
Building awareness about coral reefs, their diversity and the services they provide,
helps greatly in mitigating the threats to these fragile ecosystems. Awareness at the

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community level is most effective as it can help to encourage users of coral reefs to change
their behavior to sustainable use of these ecosystems. Awareness at national level - through
the media and conservation education - is essential to ensure that policy makers integrate
coral reef conservation into all stages of development. It is also critical to ensure that land
based environmental issues – such as unplanned or badly planned inland development and
pollution-are prevented to safeguard coastal ecosystems such as coral reefs.
In response to the growing threats to coral reefs around the world, 1997 was
designated the International Year of the Reef (IYOR) worldwide. Year 2008 was also
designated an International Year of the Reef.
Reef Resilience
Adapting to climate change is, perhaps, the biggest challenge that coastal managers face
today in respect to coral reef conservation and management. Understanding why some reefs
do not succumb to bleaching while others nearby do (i.e., why they are resistant) and why
some ‘bounce’ back quickly while others do not (i.e., why they are resilient) has become
extremely important. The Nature Conservancy and its partners have developed an R2-Reef
Resilience Toolkit that is designed to help managers prepare for and respond to coral
bleaching events.
Supporting participation and sustainable livelihoods in reef dependent communities:
The connection between poverty and coral reef ecosystems is significant: two thirds of all
countries with reef areas are developing countries, and a quarter of these are least Developed
countries.
Coral reefs provide important resources for the poor, and contribute to national
economies. The current trend of increasing threats to reef resources is likely to affect poor
communities, who are dependent on coral reefs. To make things worse, management of coral
reefs for conservation purposes often restricts community access to these resources, leaving
them even fewer livelihood options. Often, these restrictions are not followed by
communities, who have little understanding of or involvement in the management process.
It is now well recognized that such communities need to be offered alternatives for
their livelihoods in order to ensure that coral reefs are not further damaged, as well as to
alleviate poverty in coastal areas. Therefore, coastal managers are shifting towards more
integrated and participatory approaches to reef management and conservation. Such
approaches include identifying and supporting alternative livelihoods to reduce dependence
on coral reefs, as well as enhancing current livelihood activities to make them more cost and
resource efficient. Limited and controlled local use of coral reefs is now advocated in certain
circumstances, instead of blanket restrictions on use. Rights to reef access and resolution of
conflicts over resource use, community involvement and collaborative management are now
being incorporated in to reef management.
New management initiative
It is now understood that ‘standard’ methods of coastal zone management have not
been successful in achieving sustainable development and conservation goals and that a shift
in approaches is needed.

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Shifting from small, isolated management efforts to large-scale networks using collaborative
management is now the trend. Increasing the area of reefs under high protection is a major
thrust of this shift and 33% of the Great Barrier Reef has now been declared as high
protection zones or no-take areas - where harvesting is not permitted. Collaborating to create
larger networks of MPAs is yet another approach that has been favored by major NGOs such
as Conservation International, The Nature Conservancy and the World Wildlife Fund who are
developing training modules to identify and develop a network of MPAs in Asia based on
areas of highest biodiversity. Others are assisting managers to cope with climate change
impacts. Another change is the effort to focus research on real-life problems that resource
managers face (Wilkinson, 2004). There is also a definite trend towards integrated
management which understands that unsuitable land use inland poses serious threats to the
coastal zone. Therefore, it emphasizes inland land use and watershed management. An
ecosystem approach - integrating ecological, economical and social principles in a holistic
manner, involving all stakeholders, is now the favoured approach.

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REFERENCES
1. Miththapala Sriyanie. 2008. Coral Reefs. Coastal Ecosystems Series (Volume 1).
Ecosystems and Livelihoods Group Asia, IUCN. Pp 01- 20.
2. Weir Wendy et. Al. 2004. Corals Reef Teachers guide.
3. Holing, Dwight. 1990. Coral Reefs. San Luis Obispo. California: Blake Publishing.