Knowledge Nugget | Why are corals being moved? Understanding coral reefs and their importance

Key takeaways:

1. ZSI informed this development to the committee overseeing the implementation of biodiversity-related issues during the fourth meeting in November last year. The minutes of the meeting were made public by the Andaman and Nicobar Island Integrated Development Corporation Ltd (ANIIDCO) only on June 10.

2. ZSI has identified “four new translocation sites on the west coast of Great Nicobar Islands and undertake the translocation of coral colonies and Giant Clams from the project impact area as per EC (Environmental Clearance) and CRZ (Coastal Regulation Zone) clearance conditions prior to the commencement of project works”.

On-map location of Galathea Bay (File photo)

3. In compliance with the condition for granting Environmental Clearance, an environmental management plan is implemented.  In this regard, three independent Monitoring Committees are formed. These are:

(a) Committee to oversee biodiversity-related matters.

(b) Committee to oversee pollution-related matters.

(c) Committee to oversee welfare and issues related to Shompen and Nicobarese.

4. The biodiversity-related committee is tasked with overseeing wildlife conservation plans and actions to mitigate the project’s impact on the endemic Nicobar Megapode, leatherback marine turtles, saltwater crocodiles, Nicobar Macaque, Robber Crab, coral translocation, and other birds found only on the island.

(Source: IUCN Red List, ZSI)

Before we move to understand coral translocation, let’s understand what coral reefs are.

5. Corals are animals from the phylum Cnidaria. They comprise hundreds to thousands of living organisms called polyps, each only a few millimeters in diameter. Each polyp has stinging tentacles to capture food such as plankton and small fish. It lives in groups of hundreds to thousands of genetically identical polyps known as a ‘colony’, which is recognised as coral.

6. Corals are characterised as either hard or soft coral. The architects of coral reefs are hard corals, which form complex three-dimensional structures over thousands of years.

7. At the coral base is a hard, protective limestone skeleton called a calicle, which forms the structure of coral reefs. Reefs begin when a polyp attaches itself to a rock on the seafloor, then divides, or buds, into thousands of clones. The polyp calicles connect to one another, creating a colony that acts as a single organism.

8. The reason for the colorful appearance of corals is the microscopic algae that live inside coral cells, called zooxanthellae. These algae perform photosynthesis, bringing vital food and nutrients to the corals.

What is the significance of coral reefs?

• Protection from big storms and floods. Coral reefs act like low-crested breakwaters and absorb 97% of wave energy.
• Underwater cities that support marine life. A single reef can support thousands of different marine species.
• Act as ‘wave breaks’ between the sea and the coastline and minimise the impact of sea erosion.
• Produce commercial goods and services worth around $375 billion every year.
• New ingredient source for some medicines to be explored by scientists. Eleutherobin, that is believed to slow cancer cell growth is found in a common species of soft coral
• Referred to as “rainforests of the sea”, existed on the Earth for nearly 450 million years. Australia’s Great Barrier Reef is the largest in the world, stretching across 2,028 kilometres.

In India, coral reefs are protected in the same way as the tiger or elephant, under Schedule I of the Wildlife Protection Act (WPA), 1972.

How are Coral reefs translocated?

1. ZSI is dedicated to monitoring coral reef translocation. For restoration purposes, it successfully moved over 16,000 corals in the Gulf of Kachchh to new locations. In a project in the Andaman Islands since 2017, ReefWatch Marine Conservation has transplanted coral fragments on to nine artificial structures totalling a 20 square metre area.

Infographics from NotebookLM

2. In a three-year-long project in Sindhudurg, corals were cultivated — fragments of corals were taken and attached to concrete frames with the help of nylon threads — and then left on ocean beds at a depth suitable for their growth.

3. The ZSI’s coral conservation plan for the Great Nicobar project states that the success rate of this project varied from above 90 per cent for restoration to 68 per cent-85 per cent for coral transplants.

4. It also states that coral colonies are to be extracted using a coral-cutting saw, hammer, chisel, and a hydraulic underwater hammer drill. Coral colonies will be translocated entirely as a whole object, lifted from the sea bottom, and loaded onto carrying trays fixed at the ship’s bottom with lift bags.

5. Experts, though, called the task of moving entire coral colonies “near impossible.” Marine biologist and independent researcher Vardhan Patankar, who has been researching coral reefs found off the Nicobar islands since 2005, said that globally, coral translocations have had limited success.

BEYOND THE NUGGET: Great Nicobar Island (GNI) Mega Project

1. In February 2026, the National Green Tribunal (NGT) cleared the way for the government’s Rs 81,000-crore Great Nicobar mega infrastructure project, noting its “strategic importance” and observing that there were “adequate safeguards” in the project’s environmental clearance.

2. Great Nicobar Island covers 910 sq km and is home to India’s southernmost location, Indira Point.

3. The government’s main goal on the island is to create an economic and defence hub. This goal rests on four pillars:

• An integrated township that will include defence facilities
• A transshipment port
• A civil and military airport
• A 450-MVA gas and solar power-based plant

4. Initially driven by NITI Aayog, the project’s implementing agency is now the Andaman and Nicobar Island Integrated Development Corp Ltd (ANIIDCO).

5. Of the cumulative area earmarked for the project, around 149 sq km will be used for the integrated township, 8.45 sq km for the new airport, 7.66 sq km for the port and .39 sq km for the power plant. The integrated township will include residential, commercial, tourist, logistics and defence facilities.

6. The transshipment port will be located on the southern tip of Great Nicobar at Galathea Bay, an ecologically important area that is home to the nesting sites of Leatherback turtles, and where the Galathea River drains into the sea.

Post Read Questions

(1) Consider the following statements: (UPSC CSE 2018)

1. Most of the world’s coral reefs are in tropical waters.

2. More than one-third of the world’s coral reefs are located in the territories of Australia, Indonesia and Philippines.

3. Coral reefs host far more number of animal phyla than those hosted by tropical rainforests.

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

(2) Which of the following have coral reefs? (UPSC CSE 2014)

1. Andaman and Nicobar Islands

2. Gulf of Kachchh

3. Gulf of Mannar

4. Sunderbans

Select the correct answer using the code given below:

(a) 1, 2 and 3 only

(b) 2 and 4 only

(c) 1 and 3 only

(d) 1, 2, 3 and 4

(Note: Coral reefs require pristine, clear sunlight, high salinity to grow. However, at Sunderbans influx of river sediments create muddy and low salinity conditions.)

     Answer Key

1. (d)      2. (a)

(Sources: Coral reefs damaged: What’s the big deal?, How corals off Mumbai’s coast will be moved, As NGT clears Great Nicobar project, a look at its strategic importance and ecological fallout, 4 sites on Nicobar west coast identified for coral translocation, says Zoological Survey of India)

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