River Dolphins go missing in Sunderbans as water salinity rises-National aquatic animal no longer sighted in the central and eastern parts of the archipelago, according to a recent study

• Rise in salinity in the water system that makes the Indian Sunderbans has resulted in a decrease in population of the Ganges River Dolphins in the region.
• A recent study covering 100 km of rivers and channels around the Sunderbans has revealed that the national aquatic animal is no longer sighted in the central and eastern parts of the archipelago.
• Only in the western part of Sunderbans, where the salinity is lower, could researchers find some evidence of the species.
• The details of the study have been published in Journal of Threatened Taxa, in an article titled Possible Range Decline of Ganges River Dolphin Platanista Gangetica in Indian Sundarban.
• The rise in sea level, triggered by climate change, is one of the reasons for the increase in salinity of waters of rivers and channels.
• “Hydrological modifications like water diversion and commission of large barrages upstream have had a great impact on the salinity profile of the rivers downstream in the Sunderbans,” the publication stated.
• In the study, the researchers noted a higher rate of encounter with the species in rivers and stretches that had limited use of motorised boats, less river traffic and more country boats.
• Classified as endangered by the IUCN Red List, the species was once found in tributaries of the Ganga in West Bengal.
• Researchers and experts said the sighting of the dolphin has dipped over the years in the 534-km stretch from Farakka Barrage to Sunderbans.

The Hindu