Revival of Reefs in the Gulf of Mannar
Kartavya Desk Staff
Syllabus: Environment
Source: TH
Context: Coral reefs in the Gulf of Mannar, Tamil Nadu, are witnessing revival through two decades of scientific restoration efforts.
About Revival of Reefs in the Gulf of Mannar:
Coral Reefs:
• Coral reefs are marine ecosystems formed by calcium carbonate structures secreted by corals.
• Known as “rainforests of the sea”, they: Support ~25% of marine biodiversity. Protect coastlines from erosion. Provide livelihood through fisheries and eco-tourism.
• Support ~25% of marine biodiversity.
• Protect coastlines from erosion.
• Provide livelihood through fisheries and eco-tourism.
• Gulf of Mannar reefs: Spread across 21 islands, rich in Acropora, Montipora, Porites and other species.
Causes of Coral Degradation:
• Anthropogenic Causes: Coral mining (1960s–1990s). Overfishing, destructive fishing gear, pollution. Coastal development, sedimentation.
• Coral mining (1960s–1990s).
• Overfishing, destructive fishing gear, pollution.
• Coastal development, sedimentation.
• Climate Change Causes: Rising sea surface temperatures → mass bleaching (2010, 2016). Ocean acidification reducing resilience.
• Rising sea surface temperatures → mass bleaching (2010, 2016).
• Ocean acidification reducing resilience.
Coral Restoration Efforts in Gulf of Mannar:
• Led by SDMRI & Tamil Nadu Forest Department (since 2002).
• Methods: Artificial substrates – concrete frames, clay pots, cement slabs. Artificial Reef Modules – Triangular (TARs) & Perforated Trapezoidal (PTARs). 20 coral species transplanted; fast-growing Acropora showed highest survival.
• Artificial substrates – concrete frames, clay pots, cement slabs.
• Artificial Reef Modules – Triangular (TARs) & Perforated Trapezoidal (PTARs).
• 20 coral species transplanted; fast-growing Acropora showed highest survival.
• Scale: 51,183 coral fragments transplanted on 5,550 substrates. Restored ~40,000 sq. m of degraded reefs.
• 51,183 coral fragments transplanted on 5,550 substrates.
• Restored ~40,000 sq. m of degraded reefs.
Outcomes:
• Survival Rate: 55–79%, with some species showing 89% survival.
• Biodiversity: Coral recruits in TARs rose from 1.23 (2004) to 24.77 (2020).
• Fish Density: Rose from 14.5 (2006) to 310 (2020) per 250 m².
Challenges to Coral Reefs:
• Repeated bleaching due to global warming – Rising sea surface temperatures stress corals, expelling symbiotic algae and leading to large-scale mortality events.
• High cost and labour intensity of restoration – Coral transplantation and artificial reef deployment require trained divers, resources, and long-term monitoring, making it expensive.
• Dependence on fast-growing species risks genetic imbalance – Overuse of Acropora corals in restoration increases vulnerability to diseases and reduces ecosystem stability.
• Ongoing pressures – plastic pollution, coastal projects, tourism – Marine debris, unregulated coastal development, and mass tourism degrade coral habitats and disrupt natural recovery.
Way Ahead:
• Scale up restoration across Gulf of Mannar and other reef sites in India – Expand successful models to Andaman, Lakshadweep, and Lakpat reefs to cover more degraded zones.
• Train local fishing communities as reef guardians – Empowering coastal communities ensures stewardship, sustainable fishing, and long-term coral monitoring.
• Use technology – AI, drones, remote sensing for monitoring – Advanced tools enable large-scale reef mapping, bleaching alerts, and real-time tracking of coral health.
• Develop heat-resistant coral strains via assisted evolution – Breeding or genetically enhancing corals for higher thermal tolerance can reduce bleaching vulnerability.
• Strengthen global partnerships under SDG-14 & Paris Agreement – International cooperation provides funding, technology, and shared best practices for reef conservation.
Conclusion:
The revival of corals in the Gulf of Mannar proves that scientific innovation, policy support, and community participation can bring marine ecosystems back from the brink. It is a model for climate adaptation and biodiversity conservation. Sustained efforts will ensure that India’s reefs remain both an ecological treasure and a livelihood source.