MYSTERIOUS
WORLD OF CORAL REEFS

Coral Reefs in Andaman & Nicobar Islands

Mushroom coral {Fungia sp.)Mushroom corals appear like mushroom. Fungia sp. are solitary and lie free on the substrate. They are known to be able to move about on a reef. Other important mushroom corals are Heliofungia actinimorphis, Herpolitha Umax and Polyphyllia talpina.

 

Brain corals(Lobophyllia sp.)Brain corals are large boulder -shapped corals with appearance of brain. Some brain coral species are Lobophyllia sp., Symphyllia sp. etc.

Octo coral (Heliopora coerulea) has a hard skeleton arranged in upright elongated flat curved plates. It contains an iron pigment and internally is coloured blue. The external colour is light grey.

Montipora acquituberculataMiscellaneous Forms - Different species of Montipora exhibit different forms. While Montipora stellata has upright branches, Montipora acquifuberculata grows in a laminate form. Pavona species shows foliaceous form where the small polyps have their internal partition joined to form an intricate pattern and giving it a flowery appearance. Other forms include round bubble coral, tipped bubble coral, tree coral, disc coral, cave coral, serpent coral, hedgehog coral, bracket coral etc.

REEF COMMUNITY

The group of animals and plants found in a reef is known as the reef community. It can be divided broadly into two main groups:

a) Reef buildersReef builders - Reef builders comprise organisms which contribute to the building of a reef. Most important among them are hard or scleractinian corals. Their lime-stone skeletons are the major component of the calcareous matter I which forms a coral reef. Another reef | builder is the calcareous red algae which help in binding coral skeleton and I strengthen them against erosion. In addition, some green algae help in consolidating reef sediments.

b) Reef dwellers - They do not help in reef formation but take part in energy transfer in a reef community's food webs. They may be either resident species which remain in the reef throughout their life or may be visiting species which spend only part of their lives in the reef, often for breeding purpose or for searching specific food available in the reef.

Sea-anemone toxinCommon coelentrate reef I dwellers are jelly fish and sea-anemone. Jelly fishes do not stay around coral reefs all the time but during certain season they appear in large number. Some are capable of inflicting very severe stings which can cause shock to swimmers who are allergic to their Sea-anemones are found throughout the reef slope and edge as well as the deeper parts of the reef flat. Star-fishThe sea - anemone houses certain colourful fishes like clown fishes which attract other fishes. These fishes are seized and consumed by the sea-anemone.

The crustacean dwellers include a variety of crabs, lobsters and shrimps. The molluscs include the top shell (Trochus nilotica), turban shell (Turbo marmoratus), sacred chunk (Turbine/la pyrum fusum), Cowries (Cypraea spp.), black lip pearl oyster (Pinclada margaritifera), Giant clam (Tridacna sp.) etc. The echinoderms include common star fish (Protoreaster nodosus), brittle star (Ophiolepsis sp.), the destructive Crown of Thorns (Acanthasterplanci), sea cucumbers, sea-urchins etc.

Sea-water around these islands is reported to have as many as 1200 species offish and of this 571 species are reef fishes. Common reef fishes found here include butterfly fish, clownfish, parrot fish, cardinal fish, goalfish, wrasses, surgeon fish, moorish fish, stone fish, scorpion fish, eels, triggerfish etc. which add more colours to this fascinating reef world.

Other important vertebrate dwellers are sea turtles and sea snakes.

IMPORTANCE OF CORAL REEFS :

- Prevent coastal erosion and storm damage.

- Primary producers in the coral reefs are very diverse and are one of the most productive ecosystems of the world.

- Are important breeding and nursery ground for a large number of commercially important fish and shellfish.

- Provide shelter to juvenile fish and larvae of many organisms.

- Provide sustenance and employment to the people living around.

THREATS :

(A) Natural threats :

• Hurricanes, cyclones, strong waves damage corals

• Diseases like white-band disease

• Climatic changes like change in sea-surface temperature may lead to coral bleaching.

• Predation by 'crown of thorn' starfish (Acanthaster planci) and corilivorous fish

(B) Anthropogenic threats :

• Increased sedimentation and siltation in coastal waters.

• Sewage and eutrophication.

• Destructive fishing methods.

• Deforestation and faulty agricultural practices.-

• Oil pollution.

• Faulty anchorage of boats /

• Illegal collection of marine resources

• Reef walking and faulty diving in reef areas.

Management Practices:

The Department of Environment & Forests, A & N Administration looks after the management of the corals and coral reefs. Collection of corals is prohibited under sec-11 of the Andaman & Nicobar Islands Shell Fishing Rules, 1978. Damage to corals and coral reefs in a National Park or wildlife Sanctuary is an offence under wildlife Protection Act, 1972 and mining of corals is also prohibited under Coastal Regulation Zone notification of 1991. The Administration has declared a number of reef areas as National Parks and wildlife Sanctuaries with a view to provide better protection and effective management.

(C) Important coral reef areas A & N Islands:

Coral reefs are found almost all along the coastal areas of A & N Islands. Important areas where one can view a variety of coral reefs include Mahatma Gandhi Marine Natonal Park, Rani Jhansi Marine National Park, North Reef Island Sanctuary, Smith Island, Ross Island, Avis Island, Lamia Bay, Harminder Bay, Cinque Island, Campbell Bay, Nancowry group of Islands etc.,

Mahatma Gandhi Marine National Park 

 

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