By Natasha Rego, May 21, 2021 15:02
There was once a 15-km-long stretch of coral in the Gulf of Kutch, off the coast of Gujarat. It was possibly everything a healthy reef needed to be — beautiful, colourful, full of life. But about 50 years ago, it started to fade. “We don’t know what triggered it,” says Sajan John, head of marine projects at the NGO Wildlife Trust of India (WTI). “But it’s likely that the sediment load increased with the setting up of ports and oil and gas refineries along the coast. The branching corals, those that make a reef beautiful, are also the most sensitive to changes in water conditions. And they perished.”
What remains is a patchy stretch where the WTI has been working to restore the corals since 2008. It is one of the oldest coral restoration programmes in India.
Not far away, the Zoological Survey of India and the Gujarat government have begun working on their project to regenerate the corals too, since January 2020.
The branching corals aren’t back yet. WTI tried, for the first few years, to reintroduce them. “But it is difficult for these to spawn and reproduce in the prevailing harsh environmental conditions,” says Praveen Kumar, a marine biologist in charge of the WTI coral regeneration programme. “So we are trying to populate artificial reefs with rescued-coral boulders.”
With the help of local fishermen, Kumar collects broken coral from the intertidal zone and places it in an underwater “nursery” closer to shore, to get acclimatised.
“The pieces are then transferred to artificial reefs called coral gardens, close to where the natural reefs are,” Kumar says. These coral gardens are conical structures created on the ocean floor by piling up limestone or basalt boulders with a 1-metre base diameter and height of 1 metre. WTI has created 1,240 such cones over the last six years, with a total surface area of 3,149 sq metres spread out across an area of 30,000 sq metres.
“The coral gardens act as substrate where floating coral larvae can settle and act as good fish aggregators,” Kumar says.
The government initiative, meanwhile, is using a process that works on the principle of mineral accretion, one that NGO ReefWatch India (RWI) has been using in the Andaman Islands for a few years. Since 2018, the RWI coral restoration programme has been rehabilitating broken off pieces of coral using metal frames and mild electric current, powered by solar panels.
“Not far from the natural reef, we have installed 10 metal frames in various shapes,” says RWI executive director Nayantara Jain. “Fragments that are broken off by storms, anchor damage, bitten off by fish, any pieces we find fallen on the sand are rescued and attached to this structure, using wire, zip ties or thread, depending on the size. A mild electric current (generated through solar panels) is then passed through it.”
This technique is based on the principle of electrolysis. Calcium carbonate, a primary component of coral, and other minerals are separated from the water and deposited onto the metal frame, helping the coral grow much faster than it naturally would.
Once put it place, the coral is monitored periodically, the metal frames maintained as required and data on the growth rate collected.
Owing to the near-pristine condition of the Andaman waters, RWI is also able to work with a wider variety of species, and several branching corals adorn their metal frames too.
Meanwhile, in Goa, a regeneration project is being helmed by a banker-turned-diving instructor and citizen scientist. Through NGO Coastal Impact, Venkatesh Charloo and a team of divers transplant broken fragments of coral in the waters around Grande Island, through a process called micro-fragmentation. They started this in May 2020. Charloo noticed the bleaching of corals around his diving sites, which were threatened by uncontrolled algal growth, owing to changes in water conditions.
The process is simple and involves using a special epoxy glue to stick fragments onto the undersides of floor tiles. Each tile is called a bed. These beds are then fastened to a metal frame in the ocean, where they remain until they acclimatise and start to grow.
“We have transplanted 192 fragments as of now,” Charloo says. “Once a month, each fragment is measured, algal growth around the nursery is cleaned up and the glue and cable ties are checked. They grow at a very slow pace. At some point we will take them out of the nursery and place them on the reef so that they can propagate.”
To fund these project, the fragments are up for adoption. A person can donate money for the maintenance of a fragment, and in turn receive a certificate of adoption, tax exemption and regular updates on how the fragment is doing. “So far, 35 fragments have been adopted,” Charloo says.
“Artificial reefs are a desperate but probably inevitable attempt to repair the damage caused by human arrogance and ignorance,” says environmental activist Bittu Sahgal, founder of the Sanctuary Nature Foundation. “Natural corals should be recognised as vital survival and economic infrastructures.”