Underwater sculpture by Jason de Caires Taylor for an artificial reef project in Grenada
Our oceans are full of tiny organisms constantly sinking down towards the sea bed, attaching to any hard, secure surface such as a rock outcrop. These attachments are a kind of colonisation that creates the basis of a natural reef system. Only 10 to 15% of the sea bed has a solid enough substratum that allows the formation of reefs. Reefs attract and harbour diverse forms of marine life and also provide sanctuary for marine life to breed.
Artificial reefs are human-made underwater structures that allow and harbour marine life in featureless ocean beds. Some artificial reefs can improve hydrodynamics that promote surfing and sometimes contain sea erosion. They also ease the pressure on existing reef systems that have been over-fished or over-visited, and provide new habitat for marine life. They are usually constructed with secure, durable and environment friendly material and can form naturally in wrecks of sunken ships and submerged parts of oil platforms.
Artificial reefs for fish aggregation go way back in history. During the 17th century reefs of building rubble and rocks were used in Japan to grow kelp, while the earliest recorded construction of artificial reef in the US is from 1830s when logs from huts were used off the coast of South Carolina to improve fishing.
Shark hunters of Thuthoor, Kanyakumari, who fish along the entire Indian coast know locations of sunken ships and hook sharks and other fish from the waters around these wrecks. They say the Bombay High offshore drilling platforms are rich in marine life but they cannot fish there for security reasons. In the 80s and early 90s, several artificial reefs were laid on the south east and south west coasts of India. These were primarily done to aggregate fish for traditional fishermen.
In the Trivandrum Kanyakumari coast, artificial reefs were first laid out in the late 80s and early 90s. In Thumba, Kannanthura and Puthiyathura villages, triangular concrete modules were laid at a depth of 12 to 14 fathoms, and in Adimalathura, bamboo modules were used at 14 fathoms, with financial and technical support from the Trivandrum based Programme for Community Organisation (PCO). In Puthiiyathura, the modules were laid out near a natural reef so it could help regenerate the reef.
Between 1988 to 1994, artificial fish habitats were laid in a number of villages in Trivandrum – Marianad, Thumba, Kannanthura, Valiathura, Adimalathura, Puthiyathura, Paruthiyoor and Kollemcode.
In Kanyakumari, despite the coastline having a number of rock outcrops, fishermen have been laying artificial reefs. In Mulloorthara and Enayam, reefs were laid out under financial and technical assistance from SIFFS, an NGO that also played a major role in laying reefs with common ownership in the Trivandrum area.
On the east coast, around the same period, MCRC and CreNIEO were the two NGOs supporting the laying reefs in two villages, Olcotkuppam and Chinnandikuppam, in Chennai. Concrete rings and palm fronds and leaves were used in combination to attract both bottom and pelagic fish.
Artificial reef made of limestone
Fish aggregating devices and artificial reefs were primarily used by beginners and aged fishermen who operated rowing or sailing craft. It was an easy way of finding some fish for subsistence. These devices also came handy in lean months providing traditional fishermen with some fish to eke out a living. They are also seen as a way of supporting non-motorised fishing communities by providing them new resources close to the shore. The international demand for cuttlefish has seen a surge in the fishing of these cephalopods that are found mainly in reefs. Now, about 90% of the cuttlefish is brought in by trawlers and artificial reefs can balance the scales in favour of traditional fishermen.
Artificial surfing reefs have been created for surfing, coastal protection, habitat enhancement and coastal research. The world's first attempt was made in El Segundo, near Los Angeles, in California. An artificial surfing reef constructed of over 400 massive, geo-textile bags (each one larger than a bus) filled with sand was constructed in 2000 at Narrowneck on the Gold Coast of Queensland, Australia. This artificial reef had two objectives: stabilizing beach nourishment and improving surfing conditions.
In India, the first attempt at creating an artificial surfing reef was carried out at Kovalam, Kerala, a popular rocky beach, by ASR, a New Zealand company. The reef was laid, earlier this year, in a cove formed by the lighthouse and the beach where waves often criss-crossed due to the bay effect. Giant geo-textile bags with a life of over 40 years and filled with sand are the building blocks of the reef. The crest of the 500-metre-long reef has been placed just below the low tide line. It has been placed at a depth of 3 to 7 m so that the reef will block breakers more than one-metre high, leaving only small waves to wash up the shore.
This project was mired in controversy over the usage of tsunami rehabilitation funds for recreational purposes, in the name of coastal protection. The project's initial cost of Rs.4 crores was hiked to Rs.8 cores midway. An EIA was not carried out, allege environmentalists and fishermen groups. To add to this, some geo-textile bags of the reef washed up on the beach provoking further outrage from coastal communities in the region and spurring activists to demand for a judicial enquiry.
The laying of the Boscombe surfing reef
Surfing reefs have never quite managed to achieve their objectives anywhere in the world. The Boscombe surf reef by ASR, in the UK failed to generate the required waves for surfing. The impact of such reefs cannot be assessed easily as there are many factors at play when the ocean breaks on a beach. In Kovalam, beach combers say the reef works only if the waves are high. "Waves are more regular and unbroken at the Light House Beach,” says Rajendra Prasad, an aquaculture consultant who works in Kovalam.”Before, waves used to be erratic and there were fewer surfers," he says; "the washing up of geo-textile bags was a tragedy. They should do a follow up and set things right."
Despite all negative feedback, proponents of artificial reefs should be lauded for their efforts towards the protection of the coasts and beaches - they haven't quite reached there but they will, as this can be a lucrative way of protecting coasts and reviving reef ecosystems. Commerce has driven many successful maritime innovations in the past so there may be light at the end for artificial reefs in an ocean that's being exploited at an alarming rate.
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