RECKLESS DISREGARD

India is set to expand seaweed cultivation along its coastline by promoting Kappaphycus alvarezii, a known invasive species that has smothered coral reefs in the Gulf of Mannar over the past two decades. Should the country instead focus on its native species?

- AKSHIT SANGOMLA

AKSHIT SANGOMLA travels to coastal villages across Goa, Gujarat and Tamil Nadu to explore the economic potential and environmental impacts of this exotic seaweed

SANJAY PEREIRA has been fishing along the Cacra coast of Goa all his life. So when he found a reddish-black, jelly-like substance tangled in his net this past June, he immediately knew it did not belong there. “It was an exotic seaweed called Kappaphycus alvarezii, which no one had seen or heard of in the state until 2022-23, when the fisheries department carried out a trial at four locations, including Cacra, to assess its cultivation potential,” says Pereira. He was involved in the trial, at the end of which all the seaweed was removed. “It has been just a year and the seaweed has started to grow on its own here,” he says.

The clump in his net weighed around 8 kg. Other local fisherfolk have also reported similar catches. Concerned, he informed the fisheries department, but never received a response. “We have several native seaweeds, but they do not grow so rapidly. We are worried if the exotic seaweed could impact our livelihood,” says Pereira.

Kappaphycus alvarezii is a known invasive species that has already smothered coral reefs in the Gulf of Mannar in Tamil Nadu, where it was introduced for commercial cultivation two decades ago. While the seaweed is valuable for producing carrageenan, a widely used emulsifier in foods, beverages and medicines, and biostimulants that improve crop yields, its spread poses a serious threat to local ecosystems.