Zoological Survey to soon seek nod to translocate Great Nicobar corals

5 min readNew DelhiJun 16, 2026 11:40 AM IST

ZSI has identified four sites on the west coast of the Great Nicobar Island for coral translocation. (Wikimedia Commons/Representative Image)

The Zoological Survey of India (ZSI) will soon seek a nod from the Department of Environment and Forest, Andaman and Nicobar Islands, for the translocation of over 16,000 coral colonies that will be impacted around the Galathea Bay transhipment port site under the Great Nicobar Island (GNI) project, senior officials told The Indian Express.

The government body has also begun data collection to measure sediment deposition at coral translocation recipient sites and around existing coral colonies to assess current sediment loads, said C Raghunathan, Additional Director and Scientist – F, ZSI.

Translocation of coral colonies to mitigate potential impacts of port construction activities, such as capital dredging, is one of the key conditions laid down in the environmental clearance granted for the Rs 81,000 crore mega project. Capital dredging is undertaken to create deep, navigable channels for large vessels and alters marine ecology.

Coral colonies, made up of many individual coral animals called polyps, need light to remain healthy, and a rise in sediment load from dredging activities can increase turbidity (cloudiness) and coral smothering, leading to their death.

Assessing sediment loads

In a challenge before the National Green Tribunal (NGT) against the project’s environmental clearance, ZSI had submitted that 16,150 coral colonies found within 15 metres depth of the water column and in proximity of the project may be impacted because of the project. These coral colonies need to be translocated to suitable recipient sites based on “sediment trap results.”

“ZSI has been assessing sediment load in the port project area as well as at the recipient sites. Dredging is an intensive activity and that will cause turbidity in the waters around the project area. A baseline sediment load analysis is also necessary to gauge the impact on corals,” Raghunathan told The Indian Express.

Subsequently, ZSI will also seek approval from the Ministry of Environment, Forest and Climate Change (MoEFCC) wildlife division. ZSI has identified four sites on the west coast of the Great Nicobar Island for coral translocation.

Story continues below this ad

When asked about the success rate of transplantation or translocation, Raghunathan cited ZSI’s project in the Gulf of Kutch involving restoration of degraded corals.

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.

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.

Coral translocation challenges

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.

Story continues below this ad

Patankar said that individual corals and colonies, whose size can vary from a few centimetres to that of a small car, take a decade or more to grow. He said corals require many oceanographic and ecological factors, such as the right temperature, salinity, alkalinity, nutrient load, current flow, and habitat, during translocation.

“Whatever little translocation that has happened involves translocation of fragments of corals and not large colonies. Coral composition along the Galathea River is dominated by Porites, Favia, and other large boulder corals. A coral colony consists of complex, interconnected colonies of several individual organisms and keeping all of them alive after breaking the colony is a near impossible task,” he said.

Patankar added that the challenge is magnified in Nicobar, as the waters here host some of the most biodiverse reefs in India, largely due to their close geographic proximity to the ‘coral triangle’, which is the global epicentre of marine biodiversity.

© The Indian Express Pvt Ltd

An award-winning journalist with 14 years of experience, Nikhil Ghanekar is an Assistant Editor with the National Bureau [Government] of The Indian Express in New Delhi. He primarily covers environmental policy matters which involve tracking key decisions and inner workings of the Ministry of Environment, Forest and Climate Change. He also covers the functioning of the National Green Tribunal and writes on the impact of environmental policies on wildlife conservation, forestry issues and climate change.

Nikhil joined The Indian Express in 2024. Originally from Mumbai, he has worked in publications such as Tehelka, Hindustan Times, DNA Newspaper, News18 and Indiaspend. In the past 14 years, he has written on a range of subjects such as sports, current affairs, civic issues, city centric environment news, central government policies and politics. ... Read More

Tags:

Andaman and Nicobar islands

corals