At Mandwa near Alibag in Maharashtra, the sea is carrying a new kind of crop.
For generations, Koli fishing families here went into the Arabian Sea looking for fish and crustaceans. Now, near the jetty, bamboo rafts hold rows of seaweed. The crop grows underwater for about 45 days before it is harvested, dried and sold to companies that use it in fertilisers, cosmetics, medicines and food products.
The shift may look small from the shore. For fishing families, it can change the way income arrives at home.
Along many parts of India’s coastline, fishing has become harder to depend on fully. Catch is more unpredictable, diesel costs are higher, rough weather can keep boats ashore, and a poor week at sea can mean little money coming in. Seaweed farming is gaining attention because it offers coastal families something practical: a crop they can grow in the sea while continuing to fish.
It is not a miracle climate solution. It will not replace fishing or solve coastal poverty. But it could become a useful second livelihood for families living with an increasingly uncertain sea.
First, what does a seaweed farmer actually do?
For communities long at the mercy of unpredictable tides and shrinking catches, seaweed offers a control. Photograph: (Image generated with AI)
Seaweed farming is simpler than it sounds.
A farmer or fishing family sets up ropes, bamboo rafts or longlines in shallow seawater. Small pieces of seaweed are tied to these ropes. Over the next few weeks, the seaweed grows naturally in the ocean. Once it is ready, it is harvested, dried onshore and sold.
In Mandwa, Alibag’s first commercial seaweed farm uses 50 bamboo rafts and 20 longlines to cultivate Kappaphycus alvarezii, a red seaweed used in carrageenan production. Carrageenan is a natural thickening and stabilising agent used in food, cosmetics and pharmaceuticals.
The crop cycle is short, which is one reason fishing families are interested. In the Mandwa project, one harvest takes about 45 days. Fisher Mahesh Dhake told The Times of India that seaweed farming helped increase his overall income by nearly 30 percent after declining fish catch pushed him towards shore-based work. Wet seaweed was reported to fetch around Rs 20 per kg, while dried seaweed fetched around Rs 130 per kg, depending on quality and processing.
For a family used to depending on the day’s catch, the appeal is clear. Seaweed does not guarantee wealth. But it can create another payment cycle in the background.
Why is this more sustainable than regular farming?
Seaweed grows up to ten times faster than terrestrial plants and delivers comparable biomass using less than one-tenth of the land area. Photograph: (Image generated with AI)
Traditional farming usually needs land, freshwater, irrigation, fertiliser and labour over several months. Seaweed asks for much less.
It grows in seawater. It does not need agricultural land. It does not require groundwater, borewells or irrigation canals. It does not need chemical fertilisers in the way land crops often do. For coastal families with limited land and irregular income, that matters.
In simple terms, seaweed farming uses space that farming on land cannot use: the sea.
That is why researchers and policymakers see it as useful in a country where agriculture is already under pressure from water scarcity, soil degradation and rising input costs. India produced 72,385 tonnes of seaweed in 2023, and the main cultivated species include Kappaphycus alvarezii and Gracilaria edulis, which are used for carrageenan and agar production. Seaweed is also used in food, biofertilisers, pharmaceuticals, cosmetics, animal feed and biofuels.
The sustainability argument, then, is not that seaweed will save the planet. It is that it can produce useful raw material without adding more pressure on farmland and freshwater.
What does this mean for a coastal household?
For a coastal family, the practical benefit is not abstract climate resilience. It is income that does not depend entirely on fishing.
Imagine a small fishing household. On good days, the boat returns with enough catch to sell. On bad days, diesel has been spent but the earnings are poor. During rough weather, the family may not be able to go out at all.
Seaweed changes this slightly. While fishing continues, a crop is growing close to shore. When harvested, it can be dried and sold. Women in the household can also participate in seed preparation, drying, sorting and processing.
In Mandwa, men manage the sea operations, while women are involved in preparing seed lines and post-harvest work. The project currently includes 11 cooperative members. It is not yet a large movement, but it shows how seaweed can become a shared family livelihood rather than an activity restricted to those who go deep into the sea.
Tamil Nadu offers another example. ICAR-CMFRI has supported seaweed farming among coastal fishing families, including in Ramanathapuram district. In one supported model, annual earnings were estimated at nearly Rs 96,000 per farmer under favourable conditions and multiple crop cycles.
These are not enormous incomes. But they are meaningful when seen as supplementary earnings. For families facing uncertain fish catch, a few additional harvests a year can help with school fees, household expenses or debt repayment.
How does seaweed help farming on land?
Seaweed is also useful after it leaves the coast.
Some seaweed is processed into products used in agriculture. These are often called bio-stimulants. Put simply, a bio-stimulant is a plant supplement. It is sprayed on crops to support growth, improve stress tolerance and help plants cope better with heat, poor soil or limited water.
CSIR-CSMCRI in Gujarat has developed seaweed sap technology using Kappaphycus alvarezii. This technology is used in products such as Sagarika, and institutional documents note trials across crops including rice, maize, soybean, sugarcane and pulses.
This does not mean seaweed can replace fertilisers. That would be an overclaim. The more realistic point is that seaweed-based inputs may help farmers reduce dependence on some chemical inputs over time, depending on the crop, soil and conditions.
So seaweed connects to sustainable farming in two ways: it gives coastal families a low-input crop to grow in the sea, and it can become part of cleaner agricultural input systems on land.
Why is India trying to grow this sector now?
In parts of Odisha, for instance, women-led groups engaged in seaweed cultivation are earning steady incomes from small farming areas. Photograph: (Grow-Trees.com.)
India has the coastline, but not yet the scale.
Government data says India produced 72,385 tonnes of seaweed in 2023. Research institutions have identified 384 potential cultivation sites covering 24,707 hectares across the Indian coastline. Seaweed cultivation has also been identified as a priority activity under the Pradhan Mantri Matsya Sampada Yojana to support employment and additional income for fishing and coastal communities.
NITI Aayog’s strategy for the seaweed value chain argues that India has potential to build cultivation, processing and market systems around seaweed. The report focuses on livelihoods, value addition, seed systems, processing infrastructure and better governance.
This is important because seaweed farming cannot grow only through enthusiasm. Farmers need good seed, training, permissions, insurance, buyers and processing units. Without those, seaweed remains a promising pilot rather than a reliable livelihood.
Mandwa’s farmers have already pointed to some of these barriers: weak market access, lack of insurance against cyclones or oil spills, fragmented permissions and no seed bank in Maharashtra.
So, can seaweed farming really help?
Yes, but in a specific and practical way.
Seaweed farming is unlikely to become India’s next agricultural revolution. It will not replace fishing. It will not solve climate change. It will not automatically make every coastal family financially secure.
What it can do is more grounded.
It can give fishing families another crop when fish catch becomes unreliable. It can create income without using farmland or freshwater. It can involve women in coastal livelihoods through drying, sorting and processing. It can supply raw material for industries ranging from food to biofertilisers. And it can support research into cleaner farming inputs.
That is why seaweed matters.
Not because it is a perfect solution, but because it fits a real gap in coastal India: families need income that can survive changing seas.
In places like Mandwa, that future is already visible. A family may still fish. But nearby, tied to ropes beneath the water, another harvest is growing.
