Researchers of the Department of Marine Sciences, Calcutta University, in collaboration with Nature Environment and Wildlife Society, a non-governmental organisation, have jointly documented this finding.

“Due to the global warming, salinity is on the rise in the eastern part as it is fed by tides, while the western part has comparatively lower salinity because it gets fresh water from the Gangotri glacier. So unlike earlier, when we thought of a single conservation plan for the entire forest, now we should take into account the research findings,” said Dr Abhijit Mitra, Department of Marine Sciences, Calcutta University.

Due to the variation in salinity, the fish spectrum has also been affected. The eastern part has recorded the availability of economically less valuable fishes, while the western sector is dominated by commercially viable species of fish such as Tenualosa ilisha, Polynemus paradiseus, Sillaginopsis panijus, Pama pama, Arius jella, Osteogeneiosus militaris.

According to the study, since the dissolved oxygen is relatively high in the western sector due to fresh water inflow, the stress has been increasing on the eastern side of the Indian Sunderbans. This might be probably due to the increase in the salinity, temperature and lowering of the dissolved oxygen.

Experts suggest the policy with respect to climate change should therefore be developed at two different levels to combat climate change in Sunderbans.