CORAL REEFS, ALSO KNOWN AS THE ‘RAINFORESTS OF THE SEAS’, are marine ecosystems that support a rich and colourful array of aquatic flora and fauna. Yet, not much information exists on the coral species found in India, their conservation status and threats facing them.
Launched in 2008, the Coral Reef Recovery Project is a joint venture of WTI and the Gujarat Forest Department, supported by Tata Chemicals Limited (TCL). It seeks to develop and implement appropriate strategies for the conservation of the Mithapur Reef, situated 12 kilometres south of the Gulf of Kachchh in Gujarat. The project, with initial support received from the World Land Trust, is also working in the recovery of coral reefs in Gujarat’s Marine National Park.
In Mithapur, the project envisions the creation of a model public-private-managed coral ecosystem of international standards using global benchmarks to restore degraded reefs through activities including coral transplantation and natural recruitment.
Corals are sedentary colonies of soft-bodied marine animals called ‘coral polyps’. The polyps range in size from a pin-head to a foot in length. The polyps harbour unicellular flagellated photosynthetic algae called zooxanthellae, which give the corals their colour. The corals’ dependence on these algae for oxygen and nutrients confine them to shallow clear waters that allow passage of light for photosynthesis.
There are two kinds of corals: hard and soft. Hard corals (Scleractinia) such as brain, star, staghorn, elkhorn and pillar corals secrete rigid calcium carbonate exoskeletons (or corallites) that protect their soft delicate bodies, while soft corals (Gorgonians) such as sea fans, sea whips, and sea rods lack an exoskeleton.
Coral reefs are extensive networks of calcium carbonate exoskeletons of millions of corals, fused together through adhesives secreted by the polyps, resulting in the formation of thin plates and layers over time. Coral reefs are found in tropical and semi-tropical waters. In India, four major coral reef ecosystems exist in Andaman & Nicobar islands, Lakshadweep islands, Gulf of Mannar – Tamil Nadu and Gulf of Kachchh – Gujarat.
Significance of coral reef ecosystems
Corals are sensitive to changes in water conditions brought about by natural or man-made causes, and therefore, are good indicators of a healthy marine environment. Natural geological phenomena including cyclones, storms, hurricanes, floods and tectonic shifts, or anthropogenic activities causing pollution and global warming can have an adverse impact on corals. These cause stress to the corals leading to their bleaching and eventual death.
Corals are sensitive to changes in water conditions brought about by natural or man-made causes, and therefore, are good indicators of a healthy marine environment.
Bleaching is whitening of corals as a result of death or expulsion of the symbiotic algal microorganisms – zooxanthellae. This is reversible up to a certain extent, but if the corals remain without these zooxanthellae for too long, it can result in their death.
THE MANDATES OF THE CORAL REEF RECOVERY PROJECT INCLUDE
Baseline data on coral diversity and richness
Till date, the project has identified at least 17 species of corals in Mithapur, including one that was declared locally-extinct. Two other species have been recorded but are yet to be identified. As the baseline data collection process continues, more species may be found.
Baseline data on other marine life forms
The project has additionally identified 55 species of fish, and around 150 other species including crustaceans, shells, sea weed, six sea slugs, sea snakes, sea cucumbers, sea urchin, sea anemone and jellyfish.
Facilitation of coral reef recovery
Research has shown that two species of Acropora have become extinct in the Mithapur reef. According to its mandate, the Mithapur Coral Reef Recovery Project is attempting an unprecedented reintroduction of these species by transporting fragments from areas that still harbor them, and subsequently transplanting them in Mithapur.
Agatti island in Lakshadweep was selected as a donor site on the basis of the common availability of Acropora species, as indicated by a review of available literature and subsequent groundtruthing.
Principle: While local transplantation of corals has been carried out (within the same beach, without removing them from their natural surrounding), this is the first time that live corals are being transported over a large distance and transplanted for reintroduction.
With no previous records of transportation of live corals over a large distance, the project had in its face, the immediate difficulty of keeping the fragments alive outside their natural environment for a long time during the journey from Lakshadweep to Mithapur. The basic principle was to ensure emulation of natural surrounding during the entire process of extracting the fragments, stabilisation and transport of from Lakshadweep to Mithapur.
Process: Fragments of Acropora were broken off the donor colonies and implanted on moveable substrates and stabilised. As such a move has never been reported, protocols on live coral transport were devised and tested successfully, before the actual move. Accordingly, the stabilised coral fragments were transported, covering a distance of about 1500 kms from Lakshadweep to Mithapur.
In Mithapur the coral fragments were stabilised with Lakshadweep water, and gradually acclimatised to the local sea water. The fragments were finally immersed into the natural surrounding and transplanted.
Through the entire process, observations were carried out to ensure early identification of signs of stress, for appropriate countering by getting back to the natural conditions. Stress in corals cause whitening (bleaching) due to expulsion of the zooxanthellae.