The next time you want to dig into a spiced, crunchy fried mussel or fancy some coconut-laced clam gravy while lounging in a Goa beach shack, you might have to look harder for it.
An alarmed Goa forest and environment ministry last week ordered a probe into the death of thousands of clams at Velim, a coastal village in South Goa, one of the few places along the state's coastline, where the molluscs have been surfacing for decades now.
According to experts, Goa's shellfish is also threatened by water pollution caused over the years by mining and the increasing discharge of toxins into the state's main rivers, Mandovi in north Goa and the Zuari towards the south. The clam deaths come as yet another blow to the state's traditional fish-loving population, which is already reeling under high prices on account of severe shortages in the fish catch over the last few months.
Activist Clifton D'Souza was one of those few who saw first-hand the stretch of dead clams which lay open, with sandy grime in their cavity, instead of the sought after edible tissue. He claims the discharge of raw sewage into the Sal river is the reason for the carnage.
Environment Minister Alina Saldanha, who had earlier dispatched a team of the Goa State Biodiversity Board (GSBB) to inspect the site and interact with the locals, has now ordered a detailed investigation with the help of the National Institute of Oceanography (NIO), a central marine research institute located in Goa.
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"This mysterious episode of clam deaths will need detailed investigation to determine the true causes," she said earlier this week.
According to a preliminary investigation conducted by the state environment ministry, the deaths could have been caused by a shell pathogen, shell fish toxin accumulated through filter feeding, stress induced mortality caused by hypoxia/anoxia, a very high biological oxygen demand in the lower water strata close to the sediment or salinity.
Local fishermen have been claiming over two months that there were recurring instances of clams coming up dead.
One of Goa's top marine scientists, Baban Ingole, claims that the beach state, well known for its sea-food, may soon have to bid goodbye to its mussels if it did not take steps quick enough.
"The mussel seed in the Vasco bay area is seriously depleting. Very soon Goa will not have any mussels. Most of them which are sold in Goa are from outside the state any way," he warned during an Environment Day function earlier this month.
Ingole, who works for the NIO, was also the first in 2010 to warn of a possible fish famine off Goa's coast due to pollution and overfishing to feed the state's ever growing in-bound tourism.
Subsequently, in the last couple of years, the scientific community has also been churning out research about how mining silt accumulated over the years and pollution are squelching Goa's shellfish population.
One of them was Padma Bhushan awardee and ecologist Madhav Gadgil, who has spearheaded a couple of major studies in Goa and the Western Ghats, a majestic mountain range which overlooks the state.
He blamed the loss of fish and shellfish productivity in Goa to three key factors: "Turbidity in water, increased sedimentation and oil, iron and manganese pollution."
A similar sentiment is echoed in an NIO study, authored by a team of Indian and Chinese researchers, who examined both the major rivers.
Released last year, the study blames "abundant" spillages from the ferrying of iron ore in river barges as one of the causes for river pollution.
"Since ore handling - loading in barges, transporting and reloading at the port or mid-stream in giant ships - is done in an open system there is abundant spilled-over ore material into the estuaries (of the two rivers)," the study said.
"Shipbuilding industries on the shores of both rivers may have contributed to the trace metals," the study further stated, adding that in some areas in the two rivers, pollution had reached "significant" levels.
(Mayabhushan Nagvenkar can be contacted at mayabhushan.n@ians.in)
