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Re-greening the Seas in India

Artificial Reefs

(Reverdir les mers en Inde Récifs artificiels)

Chandrika SHARMA

12 / 1997

In the coastal state of Kerala, in South India, about one million people depend, either directly or indirectly, on small-scale fishing and related activities. Over the last three decades, however, fishing grounds in the state have been severely depleted and natural reefs, essential habitats for fish, destroyed. One reason for this is the trawlers fishing in India’s coastal waters, catching shrimp for export.

Local studies have shown that many natural reefs have been destroyed. Around 150 species of once common varieties, including 135 fin-fish species, are no longer caught by the artisanal fishermen, because they have been severely depleted by uncontrolled trawl fishing. During the 1970s, overall fish catches declined and the artisanal sector’s catch fell to between 40 and 60 per cent of per-1970 levels.

Artisanal fishworkers in the region have responded to this threat in various ways, including organising themselves into unions and campaigning for more equitable fisheries development policies. Many have also adopted new technology, such as imported outboard motors (OBMs), to compete more effectively with trawlers. Often the use of such technologies cause fishermen to change from traditional selective techniques to more modern, industrial, `catch-all’ methods.

The challenge for small-scale and artisanal fisheries is to become more productive, without undermining traditional nurturing management systems and depleting the resource base.

Fishworkers from several villages in the two most south-western districts of India-Trivandrum in Kerala and Kanyakumari in Tamil Nadu-have been engaged in experimenting with ways of rejuvenating the sea bed and providing for the in situ conservation of fish stocks.

A recent experiment has been the construction of artificial fish habitats (AFHs). Such artisanal experimentation has a long history. For instance, fishworkers operating `shore seine’ nets traditionally used to dump rocks fastened with coconut fronds on the sea bed to attract fish close to the shore. More recently, fishworkers using hooks-and-lines came to associate wrecks on the sea bed with rich fishing.

Over the 1980s, the fishermen of the area constructed 19 AFHs, using locally available materials such as concrete well rings, coconut fronds and tree stumps. Site selection and choice of materials were based on customary and experiential knowledge of the fishworkers.

In 1989, the Programme for Community Organisation (PCO), a local Trivandrum-based NGO, initiated a joint project with representatives from three fishing communities based on the lessons learned from the early experiments. The new experiments involved the construction of purpose-built AFH modules in bamboo and concrete, followed by their aggregation into artificial reefs. The local NGO raised half the costs and fishworkers, the balance. A technique for lowering and accurately placing reef modules onto the sea bed was also devised, to prevent `gliding’ of AFS modules and to increase their concentration.

The ARs were established at sites selected by the fishworkers. Systematic studies of their effectiveness were undertaken by PCO in collaboration with the Intermediate Technology Development Group (ITDG). In each case, the reefs were found to act as fish aggregating devices, significantly enhancing catches. It was also found that there was rapid colonisation of the ARs by resident fish varieties.

In January 1995, a team of oceanographers from Southampton University observed that the ARs are stable and their surfaces are well colonised by marine life, providing protection and food for reef-dwelling fish. The variety of life forms is not as complex as that found on natural reefs, but, with time, a greater diversity is expected to develop.

Other NGOs, like the South Indian Federation of Fishermen Societies, as well as the Government of Kerala, have also initiated experiments with ARs. If large enough-and they would need to be about 10 to 50 times bigger-ARs can serve as underwater barriers to prevent the encroachment into near-shore waters of destructive fishing gear such as bottom trawls. They can also provide refuge for fish, and, dispersed over wide areas, ARs may serve as marine reserves and important breeding and conservation areas.


organisation de pêcheurs, technologie

, Inde, Kerala, Tamil Nadu


Experiments with ARs have helped fishing communities to develop and regenerate their local fishing grounds, ravaged from years of indiscriminate trawling. ARs have provided a focal point for communities to come together and to use their collective experience and knowledge in a constructive manner. Artificial reefs can play a role-at the community and government level-in fostering awareness of how to maintain the diversity of fish stocks and the need for sustainable fisheries management. ARs also provide a focus for the debate on issues of ownership and control of the coastal commons and on matters of ecosystem rehabilitation. Furthermore, they have a potentially important role to play in demarcating exclusive community-controlled fishing zones, and thereby facilitating sustainable community-based management of fish stocks on the basis of `harvesting’ rather than `hunting’.

It is, of course, evident that as a stand-alone technology, ARs are unlikely to form the basis of a viable artisanal fishery in the future. There is, for instance, a danger that when ARs are used as fishing grounds, increased pressure can be applied to already overexploited fish stocks. The challenge for the future is to enable more local communities of artisanal fisherfolk, who are the true guardians of marine resources, to develop, using participatory approaches, sustainable and socially responsible measures of fisheries management. For this community institutions need to be recognised as crucial stakeholders in the process of management.


Articles et dossiers

O'RIORDAN, Brian, Re-greening the seas in. Samudra Report, 1995/10, 13

ICSF (International Collective in Support of Fishworkers) - 27 College Road, Chennai 600006, INDIA - Tel. (91) 44-2827 5303 - Fax (91) 44-2825 4457 - Inde - - icsf (@)

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