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Coastal communities in Tamil Nadu are finding alternative livelihoods in aquaculture to counter challenges of rising sea levels, increasing salinity and coastal erosion

Inland fishermen feed sea bass that are reared in cage farms (Photo by N. Vinoth Kumar)

Inland fishermen feed sea bass that are reared in cage farms (Photo by N. Vinoth Kumar)

Sivagnanam is from Thiruppaalaivanam, a village in the coastal district of Thiruvallur whose Tamil name translates to desert. Despite being close to the sea, it sits in a rain shadow and droughts are common. When the rains do come, they are torrential.

The erratic weather combined with seawater inundating fields in his village forced the 58-year-old farmer to give up cultivating rice nearly three decades ago. In his search for alternatives, a friend introduced him to aquaculture, and he converted his farm into inland freshwater fish ponds located 5 kilometers from the sea.

The transition wasn’t easy. Sivagnanam tried to cultivate ornamental fish and other milkfish varieties, such as Rohu, Mrigal and Catla starting in the early 1990’s. But he wasn’t able to turn a profit. “Rearing those fish has innate problems,” he said, singling out the high cost of feed and other inputs. In addition, the wholesalers who purchased his fish didn’t offer proper prices. “Because of these problems, I suffered a huge loss and gave up,” Sivagnanam said.

Then in 2010, he made a discovery that allowed him to turn a corner: a variety of shrimp called Vannamei. “One of the advantages of cultivating this variety is you can grow it both in freshwater and in marine (water),” he said, stepping down into a pond and picking some fingerling shrimp from a net to approve of their growth.

Because the Vannamei can be cultivated throughout the year they have the ability to adapt to a changing climate, Sivagnanam explained.

Another benefit, says Muralidharan, a soil scientist from the Chennai-based Central Institute of Brackishwater Aquaculture (CIBA), is shrimp farming’s low carbon footprint. “Having studied pan-India aquaculture in coastal states such as West Bengal, Odisha, Tamil Nadu, Kerala, we realised that compared to the greenhouse gases emitted by conventional agriculture, the gases emitted by aquaculture is very low,” he said. 

A trailblazer 

Sivagnanam was the first farmer in the state of Tamil Nadu to successfully cultivate Vannamei in low-salinity fish ponds as opposed to the sea.

Farmers stand next to a shrimp pond near the sea in Thiruvallur district in Tamil Nadu (Photo by N. Vinoth Kumar)

Farmers stand next to a shrimp pond near the sea in Thiruvallur district in Tamil Nadu (Photo by N. Vinoth Kumar)

Traditionally aquaculture was done only along the shore, and farmers whose lands were inundated with salt water regarded it as wasteland and gave up farming. Then scientists from CIBA visited Sivagnanam’s village to host seminars and trainings and provide technical assistance to farmers wanting to make the transition.

By practicing aquaculture on former agriculture land, Sivagnanam paved the way for thousands of others to follow suit, helping provide alternative livelihood options in an area increasingly threatened by rising seas and soil salinity.

“In marine-water shrimp farming, you need to recycle the water for every harvest. If not, there is a high possibility of white-spot disease attack,” he said, referring to one of the most widespread and lethal viruses for shrimp populations. “But in pond-based freshwater shrimp farming, there is no need to recycle the water.”

In addition to reducing the possibility of disease, pond-based shrimp farming saves rainwater by preventing run-off, helping recharge aquifers without having to rely on groundwater.

In 2016, the Indian Council for Agriculture Research named Sivagnanam “Best Shrimp Farmer” of the year. He now has 12 shrimp ponds spread across 17 acres of his farmland in Minjur, a hamlet in Thiruvallur district, where he gives free trainings to people who are interested in learning about aquaculture.

Sivagnanam also hosts internships for students from fisheries courses, and people he has trained now own their own shrimp farms in many parts of the state. “In this district alone, around 1,000 people take part in shrimp farming,” he says.

Across the entire state of Tamil Nadu, around 50,000 people cultivate shrimp, according to data from the state-owned Marine Products Export Development Authority. Thiruvallur alone earns INR 15 million (USD 210,000) in revenue each month from the trade, adds Sivagnanam, highlighting how much more that amounts to when extended out to an entire year across the state. “Definitely, shrimp farming is a profitable and a suitable alternative to the coastal communities,” he declares.


Agricultural scientists see shrimp farming as providing an alternative for farmers whose lands have become too salt-infused for rice growing.

The state government’s fisheries department and several national fisheries and marine development authorities provide subsidies for farmers wanting to invest in aquaculture. Banks also provide loans of up to INR 2.5 million (USD 34,843). In a good year, with multiple harvests, Sivagnanam estimates that farmers can draw in profits of around INR 700,000 (USD 9,755).

Inland fishermen out hauling fish (Photo by N. Vinoth Kumar)

Inland fishermen out hauling fish (Photo by N. Vinoth Kumar)

But taking up this alternative livelihood remains a risky move in the facing of increasingly severe weather, such as cyclones and floods, particularly given a lack of insurance or other means of loss protection.

Other issues include the long delays for state governments to issue licenses to start up shrimp farms; criticism from real estate owners who allege that shrimp farms cause environmental problems; and high costs for energy needed to power electrical aerators.

Sivagnanam said the loss of one pond during the Vardah cyclone in 2016 cost him INR 10 million. “I didn’t get any compensation or insurance, because no such things exist,” he added. “Apart from extreme weather events, one of the major climate change problems these fishermen face is ‘diurnal temperature variations’,” said Kumaran, a principal scientist from CIBA.

Diurnal temperature variations are the swings between high and low temperatures that occur during the same day. That often causes stress on shrimp in inland waters, which can lead to bacterial and other viral attacks, said Kumaran, who goes by one name.

To reduce such risks, he advises shrimp farmers to follow best management practices, such as using quality seeds, testing the water quality regularly and using good quality feed.

Cage farming

Similar problems are faced by the inland fishermen of Kanchipuram, another coastal district in Tamil Nadu. It’s home to the village of Vennanguppattu, where fishermen used to fish in Adyar Creek.

But over the years they’ve found it increasingly difficult to catch enough fish, forcing them to search for other options. “Since the fish catch is continuously depleting due to various climate-change factors, we must start to use brackish water,” said K.K.Vijayan, director of CIBA.

The institute is providing locals with training and technical support to rear sea bass in cages in the creek. It zeroed in on this project because people in Tamil Nadu prefer sea bass to other fish varieties, but because these fish are found in very deep parts of the sea, it’s rare for marine fishermen who use nets to catch them.

“Lagoons, creeks and estuaries can be used for this type of cage-farming without affecting the environment,” Vijayan explained. “We chose the creek instead of using individual ponds, because the creek — being a community asset — the local people, particularly the inland fishermen, can take advantage of this type of cage-culture,” Kumaran added.

The cage-fish farming initiative started in 2016. The first harvest drew in a catch worth INR 175,000 (USD 2,439), said Charan, secretary of the APJ Abdul Kalam Fish Producers Association. “We are now waiting for the second harvest. We expect to break the record of first,” he added.

Women also take part in this type of farming and lending their labor to grading and standardising the fish catch. If provided with bank loans and insurance, Charan says, “we hope many people from our own village will come forward to join in this farming.”

This story originally appeared in Tamil. It was produced under the Earth Journalism Network’s Bay of Bengal Story Grant, a three-year initiative supported by the Climate Justice Resilience Fund.

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