What Are Artificial Reefs?

Natural coral reefs and underwater habitats have been damaged by pollution, overfishing, and climate change. To help restore marine life, people create artificial reefs using strong materials like concrete and steel.

These man-made reefs work like natural ones, giving fish and other sea creatures a place to live, find food, and reproduce. They help bring balance back to underwater ecosystems while also supporting fisheries and protecting coastlines.

How Do Artificial Reefs Work?

Artificial reefs are created by placing materials like concrete, steel, or even old ships and vehicles on the ocean floor. Over time, marine organisms attach to these structures, turning them into thriving underwater ecosystems. For example, sinking an old ship off the coast can provide a new home for corals, fish, and other marine life.

There are different types of artificial reef structures, each designed to support marine habitats in unique ways:

Concrete Modules – Specially designed blocks that provide surfaces for corals and other marine life to grow. Some, like those made with 3D concrete printing, even mimic natural coral formations.

Sunken Ships – Retired vessels are deliberately sunk to create complex habitats for fish and other sea creatures. These sites also attract divers, boosting tourism.

Reef Balls – Spherical concrete structures that encourage coral growth and provide shelter for marine life.

Fish Aggregating Devices (FADs) – Floating objects like buoys or artificial logs that attract fish, making them easier for fishermen to locate.

Benefits of Artificial Reefs

Advantages of Artificial Reefs

Artificial reefs offer a range of environmental and economic benefits:

Restoring Marine Habitats – They create new homes for marine species affected by habitat loss.

Boosting Biodiversity – By supporting diverse marine life, they help maintain ecological balance.

Supporting Fisheries – Providing breeding and feeding grounds helps sustain fish populations and local fishing industries.

Protecting Coastlines – Artificial reefs reduce coastal erosion by absorbing wave energy.

Recreational Opportunities – They attract divers, snorkelers, and anglers, boosting tourism and outdoor activities.

For example, the Tasmanian government invested $1 million in artificial reef installations and an extra $460,000 in Fish Aggregating Devices to enhance recreational fishing. In South Australia, researchers explored growing Greenlip Abalone on artificial reefs, showing the potential for sustainable aquaculture.

When designed carefully, artificial reefs can help restore marine environments, support fisheries, protect shorelines, and even create new economic opportunities.

Mumbai installed its first batch of over 200 artificial reefs in February last year at Worli Koliwada. These structures mimic natural reefs and are meant to boost fish populations, helping local fishermen deal with declining catches caused by ongoing infrastructure projects.

Artificial reefs have shown success in several parts of India, but some scientists are still unsure about their long-term effects on marine ecosystems.

The Indian government is also promoting artificial reefs as part of a nationwide effort under the Prime Minister’s Matsya Sampada Yojana (PMMSY). In August 2023, the Union Department of Fisheries announced plans to deploy artificial reefs in 3,477 fishing villages across India, including Maharashtra, over the next two to three years.

This initiative, led by the Central Marine Fisheries Research Institute (CMFRI) in Kochi, Kerala, aims to support sustainable fishing and improve livelihoods, especially for small-scale fishers.

Artificial reefs help marine life grow by creating habitats that attract fish and other sea creatures. According to a 2023 CMFRI report, these structures mimic natural environments, promoting fish aggregations and providing feeding and breeding spaces. Fishers can then catch fish that gather around these reefs.

Fish naturally gravitate toward objects in the sea, like bridge pillars or boat bottoms. Historically, fishermen used large logs to attract fish, but these decayed quickly. However, specially designed concrete structures with holes and crevices last much longer, providing stable habitats. Within three to six months, biofilm forms on the reefs, attracting larvae, plankton, and small organisms—essentially creating an underwater “kitchen” that draws fish of all sizes.

In Puducherry, fishers from Chinna Mudaliyar Chavadi village have seen major benefits from artificial reefs deployed near their shore by Kuddle Life Foundation. Previously, they had to travel 10–15 km offshore for a good catch. Now, they find abundant kingfish, tuna, red snappers, crab, prawns, squid, and even octopus just 2.5 km from shore.

Coral reefs have a unique feature known as halos—rings of barren land that encircle them, which are so distinct they can be observed from space. Interestingly, the shape of these halos can reveal valuable information about the reefs’ health, making them a useful tool for monitoring ecosystem well-being. Researchers at the University of Hawaii at Manoa have created an AI-driven solution to track and analyze these halos. By leveraging satellite imagery and convolutional neural networks (CNN) supported by Nvidia GPUs, the team was able to map and assess 300 halos over 100 square kilometers in just two minutes, a process that would traditionally take humans around ten hours.

To aid in the preservation and restoration of coral reefs, scientists are utilizing an innovative technology called biorock. This technology involves running a low-voltage direct current through steel, which causes a chemical reaction with the minerals in seawater, resulting in the growth of solid limestone on the structure. This process is similar to electrolysis, where the electric current triggers a reaction that wouldn’t typically occur. Coral fragments from other reefs can then be transferred to these biorock structures, where they benefit from the mineral crystals that form, promoting their growth.

Biorock technology serves as a valuable conservation tool for coral reefs, as it accelerates the natural processes of coral growth. When divers encounter injured coral, they can move them to these biorock structures, offering them a better chance to heal and continue growing. The coral placed on biorocks have a 50% higher survival rate compared to those left in their original location. Additionally, these structures have supported fish and lobster populations, particularly juvenile species that find shelter within the biorock framework.

As coral reefs face rapid decline, scientists are exploring innovative ways to protect and restore them. One emerging method is 3D printing, which has already been used to create everything from human organs to reef structures. 3D printing can help replace lost sections of coral by creating artificial reefs. These “fake” reefs are believed to be less susceptible to the impacts of climate change and more adaptable to shifting environmental conditions. By using 3D printing technology, scientists can replicate the texture and structure of natural reefs to aid in restoration efforts.

Experimental 3D-printed reefs have already been deployed in regions like the Mediterranean, the Caribbean, the Persian Gulf, and Australia. If successful, they could provide new habitats for fish and serve as surfaces where baby coral polyps can attach, multiply, and eventually form thriving new reefs.

Artificial reefs have also shown promising results in Kerala, Andhra Pradesh, and Gujarat over the past 30 years.