author(s)
Tasso Tayung, Pranab Gogoi, Mitesh H Ramteke, Dr. Archana Sinha, Dr. Aparna Roy, Arunava Mitra and Dr. Basanta Kumar Das

abstract
A field survey was carried out to the Bishalakhi canal (21°46'49.2"N 88°05'27.7"E) located in Sagar Island, Indian Sundarbans eco-region. The canal is a tide fed canal subjected to the brackish water influence as it is connected to the Hooghly River. A mass of freshwater sponge was found growing on submerged nylon net screen and bamboo poles structure, these structure were constructed for fish culture in the canal. Sponge specimens were carefully scraped out using a clean flat blade with the help of 'scalpel' and preserved it in 70% ethanol. Sponge samples were undergone an acid digestion process to obtain clean spicules. The spicules sample were examined under a compound light microscope for species-level identification. The sponge specimen was identified as Ephydatia fluviatilis Linnaeus, 1759 based on gemmule spicule morphology. The present study is the first report on the occurrence of E. fluviatilis from the Bishalakhi canal in Sagar Island, Indian Sundarbans eco-region, West Bengal. Studies on freshwater sponges can be useful for paleolimnological research, pharmaceutical industry, controlling of excess growth of sponge as biofouler, monitoring of water quality of the aquatic system.