Explainer: Artificial reefs — Engineering interventions to rehabilitate, manage India’s aquatic resources

India is integrating advanced technologies with policy frameworks to improve the implementation and monitoring of marine life conservation strategies. The installation of “artificial reefs” in coastal states and union territories is one such step.

To promote the restoration of aquatic life, the Department of Fisheries has sanctioned 937 artificial reef units across 11 coastal states and UTs with an investment of Rs 176.81 crore under the Pradhan Mantri Matsya Sampada Yojana (PMMSY), state Environment Minister Kirti Vardhan Singh told the Parliament on Monday. Singh was responding to a query by D Purandeswari on the progress of aquatic life restoration programmes, including artificial reefs in India.

Led by the Zoological Survey of India, the country's largest coral translocation project involved relocating 16,522 corals from intertidal and subtidal zones to suitable sites around Narara, Gujarat. Additionally, 2,000 coral cement frames — artificial reefs — have been strategically placed to ensure the long-term preservation of marine biodiversity.

The installation of artificial reefs is a part of ongoing efforts to restore marine ecosystems, enhance biodiversity and support sustainable fishing practices, the minister stated.

Understanding reefs:

A reef is a ridge of material at or near the surface of the ocean that can occur naturally. Natural reefs are made of rocks or skeletons of small animals called corals. Reefs can also be artificial, created by human beings.

According to marine scientists, coral reefs hold some of the most diverse and valuable ecosystems on the planet. They are home to over 4,000 species of fish, corals, and other marine life. Though they cover only 1 per cent of the world’s oceans, coral reefs provide habitat for at least 25 per cent of the world’s marine life with many reef species still to be discovered, they added.

Coral reefs — India:

Coral reefs in India not only provide sanctuary to marine life but also help protect the coastline from erosion. Healthy coral reefs also provide food for coastal and inland communities. In India, they can be found around the Andaman and Nicobar Islands, Gulf of Mannar, Gulf of Kutch, Palk Strait and the Lakshadweep islands.

Major institutions are involved in their management, monitoring and research. There are also specific guidelines for their protection such as the Coastal Regulation Zone (CRZ) notification of 1991 — which protects all marine resources. The ZSI plays a significant role in coral restoration and transplantation. It studies the significant impact of bleaching on hard coral species in Indian waters.

Using advanced climate modelling techniques, it also provides valuable insights for the development of effective conservation strategies and timely interventions.

Climate-resilient technologies and practices developed by leading institutions in the fields of oceanography, marine biology, fisheries, and coastal management — such as CSIR-National Institute of Oceanography, National Institute of Ocean Technology, Indian National Centre for Ocean Information Services, and the Central Marine Fisheries Research Institute, are working on conservation strategies for marine life, as per the minister.

INCOIS provides early warnings of potential coral bleaching using satellite data, helping to protect coral ecosystems and support climate resilience efforts.

The Coral Bleaching Alert System (CBAS) assesses thermal stress accumulated in coral environments based on sea surface temperature. Information derived from the CBAS is disseminated every three days, including data on hotspots, the degree of heating weeks, and time series products.

Satellite imagery, remote sensing technologies, and autonomous underwater vehicles, such as the C-bot, are used to monitor ocean conditions, including sea surface temperature, salinity, water quality, and coral health.

These technologies support early warning systems to protect coral ecosystems, enhance climate resilience, and assist in policy formulation to track ecosystem health, detect illegal fishing, and monitor coral reefs and marine protected areas, according to the minister.

Artificial reefs simulating natural settings:

Artificial reefs are structures set on the sea bed to enhance the growth of marine flora and fauna. They are “engineering interventions designed to rehabilitate and/or enhance natural habitats, increase productivity, and manage aquatic resources, including habitat improvement” by simulating natural settings.

Submerged or partly exposed to tides, the structures mimic some functions of a natural reef such as protecting, regenerating, concentrating and/or enhancing populations of living marine resources.

They serve as habitats that function as part of the natural ecosystem while doing no harm, say scientists. At times they are also known to have hosted higher fish densities than natural reefs, thereby suggesting that artificial reefs “can be effective tools for fish habitat enhancement.”

Marine ecosystems have suffered massive damage and artificial reefs can help restore small areas, addressing habitat loss and supporting the species that cannot tolerate temperature changes, they add. The installation of artificial reefs in India is a part of ongoing efforts to restore marine ecosystems, enhance biodiversity and support sustainable fishing practices. India is also one of the lead countries of GloLitter Partnership programme to reduce sea-based marine plastic litter.