At low tide, women in Goa’s coastal villages step into riverbeds with simple scraping tools, looking for clams hidden beneath the mud.
By evening, the day’s catch may be cleaned, cooked into curry, tossed with spices, or shared as part of a family meal. Across Goa, Kerala, coastal Karnataka, the Konkan coast and Bengal, this has been a familiar rhythm for generations.
For these communities, clams have long been everyday food, shaped by tides, seasons and local kitchens.
Today, that old coastal habit is being seen in a new light.
As the world searches for protein that is lighter on the planet, clams are drawing attention for a simple reason: they ask for very little to grow. They need no feed, and their environmental impact is far lower than that of many animal proteins.
In India’s coastal kitchens, a possible climate lesson has been sitting on the plate for generations.
The seafood that needs almost nothing to grow
Global food production contributes roughly 35% of human-caused greenhouse gas emissions.
Animal-based foods dominate that footprint, despite providing only about 20% of the world’s calories. For consumers trying to balance nutrition with climate concerns, protein becomes the hardest variable to solve.
This is where clams stand apart.
Unlike most farmed seafood or livestock, clams do not need feed.
They survive by filtering naturally occurring phytoplankton from water. There is no cultivation of soy or fishmeal, no transport of feed, no fertilisers, and no antibiotics. In emissions terms, that absence matters.
Much of the global conversation around sustainable diets frames solutions as shifts, moving away from meat, adopting plant-based alternatives, or embracing new technologies. Photograph: (Shutterstock)
Farmed prawns, for instance, can produce around 18.2 kg of CO₂ equivalent per 100 grams of protein, partly because mangrove forests, which store carbon, are often cleared to build shrimp farms.
Farmed fish fare better, at about 6.0 kg. But bivalves like clams, mussels, oysters have footprints several times lower than both.
Studies suggest that bivalve aquaculture generates roughly 11.1 tonnes of emissions per tonne of protein.
Compare that with beef, which can exceed 300 tonnes for the same output.
How do clams help clean water?
Clams are often described as passive organisms. In ecological terms, they are anything but.
Each clam acts as a filter, drawing in water, trapping microscopic particles, and releasing cleaner water back into its surroundings. A single littleneck-sized clam can filter several gallons of seawater a day. Multiply that across a bed of clams, and the effect becomes visible with clearer water, reduced turbidity, and improved conditions for seagrass growth.
This filtering process also plays a role in controlling excess nutrients.
Phytoplankton (tiny marine plants) absorb nitrogen from the water. Clams feed on them, incorporating that nitrogen into their bodies and shells. When clams are harvested, that nitrogen is effectively removed from the ecosystem.
Studies show that even a single clam can remove measurable amounts of nitrogen over time. At scale, this helps limit nutrient overload, which often causes harmful algal blooms in coastal waters.
Then there is carbon.
As clams grow, they form shells made of calcium carbonate, locking away carbon in a stable form. Some studies suggest that under certain conditions, bivalve farming may help store carbon in shells, though its net climate impact depends on the system.
Long before climate labels, India was eating clams
If this sounds like a discovery, it is not new to India.
Across Goa and coastal Karnataka, black clams, locally called khube, and bay clams, or tisryo, are part of the daily cuisine. Harvested from estuaries and mangroves, especially along rivers like the Mandovi and Chapora, they are collected by hand, often by women who dig into riverbeds during low tide.
In kitchens, they appear in dishes such as Khubyanche Tonak, a coconut-based curry, or are stir-fried with spices, tamarind, and chillies.
From coconut curries in Kerala to spicy khube masala in Goa, India’s clam recipes have quietly been climate-friendly long before sustainability became a global buzzword. Photograph: (The Yummy Delights)
In Kerala, clams are known as kakka or elambakka, cooked with grated coconut and served with rice. Along the Konkan coast and in Bengal, variations exist, shaped by local ingredients but rooted in the same practice.
This is not industrial aquaculture. It is small-scale, seasonal, and closely tied to ecological rhythms.
A tradition shaped by tides
In Bhatti Ward in Nerul, North Goa, the relationship with clams moves beyond the kitchen. On the second Sunday of May, the village gathers for Tisreachem Fest or the Feast of Clams.
The day begins with people stepping out of their homes carrying adoli, traditional scraping tools, and making their way to a common courtyard. There, they sit together, cleaning piles of freshly harvested clams.
By evening, the cleaned clams are cooked and shared as part of a feast.
The origins of this tradition are practical. Summer is when many villagers harvest clams, and the feast became a way to celebrate the season’s yield. Over time, it evolved into a social ritual, a moment of reunion for families and neighbours.
The question of “why clams” rarely arises here. They are simply part of life.
A lesson from India’s coastal plates
Much of the global conversation around sustainable diets frames solutions as shifts, moving away from meat, adopting plant-based alternatives, or embracing new technologies.
Clams in this scenario meet multiple criteria at once. They are protein-rich, widely available in coastal regions, and require minimal inputs to produce. Their cultivation or harvesting can improve water quality rather than degrade it.
And in India, they are an existing habit.
