Coral Bleaching In India: Causes, Impacts, And Conservation Efforts

• Recently, widespread coral bleaching has been observed along India's coastline.
• The worst-affected areas include Lakshadweep, the Gulf of Mannar, Palk Bay, and the Andaman and Nicobar Islands.

Instances of Bleaching

• Lakshadweep Islands, which are composed of coral atolls, are at significant risk.
• Bleaching has been reported in almost all coral species, including Acropora muricata and Porites cylindrica in Kavaratti Islands.
• Even relatively stress-tolerant species such as Porites lutea and Pavona varians have shown signs of bleaching in Lakshadweep.
• In the Gulf of Mannar, live coral cover decreased from 37% in 2005 to 27.3% in 2021.
• In Goa, bleaching has begun but is currently limited to one species, Goniopora.

What Are Corals?

• Corals are invertebrate animals and belong to the phylum Cnidaria.
• Corals are generally classified into:
  • Hard corals: Build reefs and have calcareous skeletons.
  • Soft corals: Do not form reefs and are more flexible.
• Coral reefs are formed by polyps of hard corals, which maintain a symbiotic relationship with zooxanthellae (microscopic algae).
• These algae provide nutrients and colour to corals through photosynthesis.

Growth Conditions for Coral Reefs

• Corals thrive in warm waters (23–29°C), with high salinity (32–42 ppt).
• They grow in clear, shallow marine waters that have stable temperatures and abundant sunlight.

Importance of Coral Reefs

• Coral reefs are called the "Rainforests of the Ocean" due to their high biodiversity.
• They support around 25% of marine life, protect coastlines by reducing storm impact, promote tourism, and act as carbon sinks.

What is Coral Bleaching?

• Coral bleaching occurs when corals are stressed due to changes in temperature, light, or nutrients.
• In such stress conditions, they expel zooxanthellae, turning white and making them vulnerable to death.

Global Status

• The period 2023–2024 is being termed the Fourth Global Mass Coral Bleaching Event.

Factors Responsible for Coral Bleaching

• Increased ocean temperatures due to climate change.
• Runoff and pollution from land.
• Ocean acidification due to increased CO₂ absorption.
• Extreme low tides exposing corals to the air.
• Biological invasions, such as non-native species.
• Epizootics (pathogen-induced diseases or bleaching).

Initiatives in India for Coral Conservation

Legal Measures

• Coral species are protected under Schedule-I of the Indian Wildlife Protection Act, 1972.
• The Coastal Regulation Zone (CRZ) Notification, 1991, issued under the Environment Protection Act, 1986, offers additional protection.

Projects and Restorations

• The Coral Reef Recovery Project - Mithapur (Gulf of Kachchh, Gujarat) was launched in 2008 by the Wildlife Trust of India (WTI) and Gujarat Forest Department.
• The Zoological Survey of India (ZSI) and Gujarat Forest Department have successfully restored coral reefs in the Gulf of Kachchh.
• The extinct staghorn coral species was reintroduced after being extinct for over 10,000 years.
• Restoration efforts used biorock technology to accelerate coral growth.

Global Coral Conservation Efforts

International Coral Reef Initiative (ICRI)

• Established in 1994 at the first CBD COP (Convention on Biological Diversity Conference of Parties).
• India is a member of ICRI.

World Coral Conservatory Project

• It aims to preserve coral species in aquariums across Europe to build a global coral gene bank.

G20 Coral Research and Development Accelerator Platform

• Aimed at accelerating innovation and research in coral conservation and restoration.

Artificial Reefs in India

Deployment of Artificial Reefs

• 300 artificial reefs have been deployed off the coast of Rameshwaram, Tamil Nadu.

About Artificial Reefs

• Artificial reefs are technological interventions to rehabilitate or improve natural marine habitats.
• They are scientifically designed and placed on the sea bed.
• These structures mimic the characteristics of natural reefs and support marine biodiversity.
• Common materials used include rocks, concrete, old tires, steel, and limestone.
• The Department of Fisheries is promoting artificial reefs under the Pradhan Mantri Matsya Sampada Yojana to rejuvenate coastal fisheries.