Kolkata, Jan 22 (IANS) With the population of the hilsa dwindling rapidly in Indian waters, a team of scientists from across the country have embarked on a project to save the fish, considered a delicacy in Bengali cuisine, and revive its numbers through various interventions.
Their efforts include efficient management of the natural reservoirs of the fish and even attempting to breed it in captivity. The fish's diet and its hormonal changes while migrating from the sea to rivers will also be examined.
Hilsa, or ilish as it is known here in Bengal, like salmon, migrates from seawater to freshwater to breed. After laying eggs, the current generation of the fish dies and the newly-hatched ones go back to the sea and repeat the same cycle again.
The fish is expensive but is widely consumed in India and Bangladesh, particularly on special occasions, in a variety of delectable dishes.
"It is important to know what the hilsa feeds on that gives it its distinct seawater taste and accounts for its nutritive value," a scientist from Central Inland Fisheries Research Institute (CIFRI) here, who did not wish to be named, told IANS.
Besides CIFRI, experts from other Indian Council of Agricultural Research (ICAR) labs too are part of the multi-dimensional project, said the scientist, who did not want to named.
But what is also baffling the experts is that while the fish's numbers are falling in Indian waters, it is flourishing in the waters of neigbouring Bangladesh. In fact, hilsa's numbers are so large that its trade makes a major contribution to Bangladesh's exports and national income.
"We must find out the reason why they are not entering our coasts. They are going to Bangladesh. The situation was the opposite 15 years ago. We must look into it immediately," Samir Bhattacharya, an emeritus professor of life sciences at Visva-Bharati University, who is also part of the project, told IANS.
He said the rising level of pollutants in the Ganges might be a factor inhibiting the hilsa's breeding.
"Another factor is indiscriminate fishing of egg-carrying hilsa. Besides, there is a possibility that the fish might be attracted by a particular chemical called chemo-attractant present in fresh water. It may be so that the levels of that chemical has declined," Bhattacharya said.
Habits like homing instincts of salmon and trout and other behaviours are well-documented abroad whereas no such data existed for hilsa, he said.
The project would also focus on hormonal changes the hilsa undergo while migrating.
"In order to successfully breed them, we must pay attention to their habitats and requirements. This is an important national matter and hilsa is a prized fish. Revival of its population needs scientists from every branch," Bhattacharya said.