Tenualosa ilisha, the Indian Shad, is one of the most important commercial fish of the Indo-Pacific region and the Hilsa fishery in India is dependent on this species. Presently, the fishery resource of the species lies largely within the Bhagirathi–Hooghly component of the Ganga River system. The annual fish catch of Hilsa from the Bhagirathi–Hooghly River has fluctuated over the years ranging between 12,733 and 20,000 t between 2000–2001 and 2010–2012.
The monsoon migration of Hilsa commences in July and gradually picks up in August. From September onwards, the magnitude of migration to the freshwater system showed a declining trend. Stretches between Nischintapur and Diamond Harbour downstream, Hooghly Ghat and Kalna in the freshwater tidal zone, and Lalbagh to Farakka in the Bhagirathi River have been delineated as potential breeding grounds for Hilsa. The intense fishing pressure in the coastal estuarine zone almost year round, especially in breeding season, adversely affects the breeding migration, spawning, and recruitment success vis a vis overall fishery of Hilsa in the system. There is an immediate need to implement effective conservation measures to protect breeders, potential breeding grounds, and juveniles for the cause of sustainable Hilsa fishery.