For generations the family of Debabrata Khuntia made a living by fishing in the Bay of Bengal and the rivers and canals of Purba Medinipur in West Bengal.

He remembers being able to catch 10 tonnes of fish a year, some of which he would keep and the rest he would sell in the market.

But those days are gone. There are few fish and Debabrata now makes a living growing tomatoes and brinjal.

He is in no doubt what is to blame. "Excessive shrimp farming."

Many farmers have shifted to shrimp farming because the money is better, he says. But that involves building shrimp ponds, feeding the shrimp and treating them with antibiotics.

At the end of the growing cycle – when the shrimp are ready for market – the water is flushed into the river untreated which, Debabrata says, has caused pollution.

"The water turns black and smells," he says. The poor quality of the water has even hit his vegetable crop.

Shrimp farming has also been blamed for social and environmental problems elsewhere in the world.

Despite those problems, India is unlikely to turn its back on the industry.

Crustacean enthusiasts among you will have noticed that we have used the term shrimp throughout this piece.

For many people the terms prawn and shrimp are used interchangeably.

Jenny Mallinson, who ran the aquarium at the University of Southampton for 43 years, makes these distinctions:

It should also be noted that in the US, India and other parts of the world the plural shrimp is used, rather than shrimps.

Shrimp farming has helped drive up incomes in rural areas and has become a valuable export business. India is the world's biggest exporter of frozen shrimp, a trade worth almost $5bn (£4bn) a year.

But some think it could be done in a way that is less damaging to the environment.

"Around one million rural farmers and coastal communities depend on shrimp and fish aquaculture, but traditional farming practices prevent them from achieving production efficiency and fail to predict diseases," says Rajamanohar Somasundaram, the chief executive and co-founder of AquaConnect.

Founded in 2017, AquaConnect sells an advisory service for fish farmers via an app. It has developed an artificial intelligence, which takes account of the farmer's resources and can advise on the best amounts of feed to use, or how to improve water quality.

The firm also offers a service which gathers data on farms that is useful for banks and insurance firms.

"The dominance of unscientific farming practices, lack of access to quality farm inputs, and identifying the right buyer to sell harvested products are always a great challenge," says Mr Somasundaram.

Other entrepreneurs want technology to take even closer control of shrimp production.

At the moment, the vast majority of Indian fish and shrimp farming is done in ponds or sea cages, but there is another way.

Recirculating Aquaculture Systems (RAS) involve circulating water through tanks. The water is continuously filtered and monitored, so very little is wasted.

Conditions can be closely controlled, with much less risk of pollution to the local environment.

With no need for a natural water source, the tanks can be located anywhere, perhaps close to big cities – a potential market for fresh produce.

More technology of business:

Shaji Baby John is the chairman and managing director of Kings Infra Ventures, one of the pioneer companies in India's aquaculture industry.

His firm has developed an RAS for shrimp farming and has built two pilot plants in partnership with a Japanese firm. One is outdoor, one is indoor.

Because the water conditions can be tightly controlled, and the shrimp closely monitored, Mr John says his RAS can produce five shrimp cycles a year. A typical pond-based shrimp farm might only manage two.

That boost in productivity means that a 1,000 sq m facility could produce up to 45 tonnes of shrimp a year.

"As it's a controlled environment the production quality is better, losses are limited," says Mr John.

But all that technology is expensive and many doubt whether RAS for shrimp will take off in India.

"There is very limited potential for RAS to become the mainstream production technology for shrimp in India," says Victor Suresh, president of the Society of Aquaculture Professionals.

"RAS has very high capital and operating costs," he points out. He says RAS might be able to compete near big cities where there might be demand for high-priced fresh and live shrimp.

But at the moment that's not a big market for India's shrimp farmers.

"For a country like India where several hundred thousand tonnes of shrimp are raised by mostly small farmers to be processed and sold into export markets, earthen ponds provide the most economically viable option," he says.

Mr John concedes that the initial investment costs of RAS farming are high, but says the quality of fish from his RAS systems is better and the cost per shrimp is lower than in traditional ponds.

Also, by using solar panels for electricity, he says the new facilities should have a low carbon footprint.

"We have gone for aquaculture focusing fully on sustainable and eco-friendly practices with zero antibiotics and zero wastage," he says.

But AquaConnect's Rajamanohar Somasundaram says shrimp farmers are a cautious group.

"Shrimp farming is a high-risk and high-reward sector. Technology solutions in the sector have to be precise or else they will result in heavy losses. This could be the reason why farmers are sceptical about technology."