In Tamil Nadu, fishermen deploy artificial coral reefs to revive declining fish stocks

Reefs do not come to mind when one thinks of India’s coastline, as coral reef establishments are limited to the waters around the Andaman and Nicobar Islands, Lakshadweep, Palk Bay and the Gulf of Mannar. However, when fishermen from Poompuhar, Tamil Nadu, reported that their fish catch was declining, the MS Swaminathan Research Foundation or MSSRF and the Tamil Nadu Fisheries Development Corporation stepped in with the solution of deploying artificial reefs.

Artificial reefs, or AR, are man-made structures deployed on generally featureless seabed to create a substratum to support a variety of marine life or where existing natural reefs have been destroyed. An AR can serve several purposes – recreational activities such as surfing, scuba diving, snorkelling, tourism; disaster management; coastal protection; managing and promoting marine biodiversity; increasing fish catch; and preventing trawling.

“It is important to identify the needs of the area and the community before installing an AR, as the models can vary with the purpose,” explained S Velvizhi, principal scientist at MSSRF’s Fish for All centre. “The AR project here aims to improve fish stocks by creating a sustainable marine ecosystem, thus providing a secure source of livelihood for local, traditional fisherfolk.”

The demand for such intervention came after villagers from Poompuhar heard of the success of the year-old AR project from the neighbouring coastal villages in Karaikal, Puducherry. Shaktivel, 35, a fisherman from Tirumalairayan Pattinam, Karaikal, said that for some time now, even as fish stocks were declining due to various reasons, operational costs of fishing were increasing. Thus, the ARs deployed last year by the MSSRF were a ray of hope.

“It has been there for just one year but I have already got four or five large catches,” Shaktivel said. “I was lucky to benefit from a bumper catch near the reef just last month. It was worth nearly Rs 30,000.” Many a times, traditional fishermen like Shaktivel return without a substantial catch, barely covering their expenses, and such bumper catches around the ARs, which support a thriving marine habitat, can save the day.

Different structures

In its Poompuhar project, MSSRF has laid nearly 60 concrete structures, weighing 800 kg to one tonne, in the compound of the Fish for All centre in Poompuhar. These structures are of three makes and each supports a different species, explained E Thamizhazhagan, development associate at MSSRF. Some of the 60 will attract lobsters, others small fish such as mackerel, small fin fishes, carangrid, and others will be home to groupers and bream fish. The structures, costing Rs 18,000 to Rs 20,000 a piece, are sunk at pre-selected spots within 15 nautical miles of the coast.

Scientists at MSSRF explained that some basic criteria for site selection include a depth of 10 m to 50 m on sandy sea bed, and assessing other factors such as tidal action, type of soil, temperature, water quality, water current, dissolved oxygen, other species in the area, nutrients, benthos and plankton. The sites should not be on clayey sea beds, trawling zones, existing coral area and fish migration routes.

Once deployed, fishing around newly sunk “reefs” is banned for at least six months to a year. Over time, the ARs develop a healthy marine habitat attracting shoals and other marine flora and fauna, after which fishing can be resumed.

Long lasting habitats

“Corals grow at just 1 cm a year, so it will take nearly five to seven years for it to look like a proper reef,” explained Velvizhi. ARs, however, are different from traditional fish aggregating devices or FADs used by fishermen. While an AR can be deployed as FADs, traditional FADs built using certain trees, barks, coir or coconut fronds – and more recently tyres, metal structures and other solid waste – are temporary and may pollute the marine environment.

“ARs, if done properly, are long-lasting habitat which includes seabed, sea grass, other smaller fishes, nutrients, and so on,” explained Hussain Mohamad Kasim, a retired scientist, formerly with the Central Marine Fisheries Research Institute. Kasim has advised government departments on AR projects in the past, and has extensively recorded various benefits of reefs. “It is particularly useful for artisanal fishermen who are marginalised by those operating mechanised boats and can significantly improve their income.”

The situation in Shaktivel’s village, dominated by artisanal fishermen operating smaller craft, is a case in point. “Unlike larger motorised boats and trawlers, we cannot venture more than 15-17 nautical km away from the coast,” he said. “Trawling really impacts our catch also.”

“Around 10-15 nautical miles is also the ideal zone for AR, thereby protecting the livelihood of artisanal fishermen using hook and line, gill netting and phased fishing on smaller crafts,” said E Thamizhazhagan.

Apart from a better catch, other benefits include reduced journey time to and from fishing grounds, hence lesser expenditure on fuel. According to Velvizhi’s calculations, ARs can boost fishermen’s income by 100% in the next three to seven years. Previous research by Kasim and others show that in some instances, ARs can increase fish catch and income by anything between 20% and 4000%.

Multiple impacts

ARs aren’t new to India. Some of the earliest recorded externally fabricated and traditional ARs in India were created by local fishermen in Kerala in the 1950s, according to this CMFRI bulletin. Interventions by organisations and scientists from Ford Foundation, CMFRI, NABARD, UNDP, fisheries departments of Kerala, Odisha, Gujarat and Tamil Nadu picked up in the 1980s and 1990s. An area of at least 1,97,750 sq km was covered by artificial reef until 2012, according to Kasim’s research.

AR has also been used to reclaim islands and prevent coral bleaching. The combined effects of ocean warming and acidification may have negative impacts on coral reef cover and marine fisheries, and exacerbate “global inequities, reducing resilience and thereby likely worsening outcomes under all climate change scenarios,” the December 2019 report by the High Level Panel on Sustainable Ocean Economy had noted.

Such impacts are evident in Thoothukudi where the destruction of marine life due to warming ocean and coral bleaching threatens the livelihood of over 10,000 fishermen, according to the project report published in 2015 by the NABARD Consultancy Services for the Department of Environment, Government of Tamil Nadu.

The AR project off the coast of Thoothukudi district, in the Gulf of Mannar, was started in 2007 with multiple aims of reviving corals and coastal habitats, preventing 21 islands from sinking, reducing trawling as well as protecting the livelihood of traditional fishermen.

Not always a success

“Not everyone can deploy AR – it is a technology and it impacts coastal communities. You can’t use the ocean as a dumping ground and call it an AR,” warned Kasim.

“Several ARs projects in the past have missed two crucial aspects – assessing the suitability of the areas and doing it in coordination with the local community,” explained Thamizhazhagan.

In Nagapattinam and Karaikal, fishermen said that their fishing nets were often damaged due to ARs which were haphazardly deployed some years ago. Such projects eventually did not support any habitats.

The success of the reef also depends on socio-economic factors. ARs are a fishing village’s common property resource, and can benefit the community as a whole. Both Velvizhi and Kasim emphasised the importance of empowering local communities in the process of laying, monitoring, management and effective implementation of AR projects.

In order to ensure community participation, MSSRF formed village monitoring committees and a project monitoring committee. They held several public meetings with panchayat leaders and fishermen for the selection of the site, models, and so on.

“Since the area where the AR is deployed needs to be undisturbed, involving fishermen makes the monitoring of the sites easy. They collectively manage the resource over time,” Velvizhi explained.

Shaktivel from Karaikal was part of MSSRF’s village monitoring committee last year. He worked with MSSRF and the local panchayat to identify the points suitable for the reef, provide inputs about their needs, and share traditional knowledge about their practices and the region.

“The local fishermen said they would prefer the reef to be on the traditional fishing ground, so that the future resources will be bountiful,” Shaktivel explained. Today, nearly 48 concrete structures at Tirumalairayan Pattinam’s common fishing along the Coromandel coast are now turning into reefs attracting a diverse range of species day in and day out.

Recalling his recent catch he added, “It seems to be working already.”

This article first appeared on Mongabay.