After a gap of over three decades, Hilsa, a high pedigree and arguably East Asia’s most prized fish, can swim back upto Allahabad in Ganga from the next monsoon. The navigational lock at Farakka has been designed in a manner to ensure the smooth and safe migration of the Hilsa shoal (group) during the three mating seasons, particularly during monsoon, by partially opening the gates only for four hours in a day.

After the construction of Farakka navigational lock in 1976, movement of Hilsa was restricted up to Farakka only. Navigational lock is a device that is used for raising and lowering boats and ships between stretches of water of different levels on river and other waterways.

“We will open the gates for only eight metres and between 1 am and 5 am, which is the preferred time when Hilsa seeks passage. This provision has been made in consultation with ICAR- Central Inland Fisheries Research Institute, Central Water Commission and Farraka Barrage Project Authority. We have designed this inhouse and have saved about Rs 100 crore,” Inland Waterway Authority of India (IWAI) vice-chairman Pravir Pandey told TOI.

 Hilsa has a history of migrating to Allahabad in the Ganga river system from Bangladesh. Though it’s a saltwater fish, it migrates to sweet waters of the Ganges from the Bay of Bengal. It travels upstream of the river during the mating seasons and returns to its natural abode after spawning. The hatchings also head to marine water, and the cycle goes on.

Pandey added for passage of vessels they need to open the gate for 25 metres width and this is a big exercise.

Union shipping and waterways minister Nitin Gadkari will announce the operation of this new navigation lock on Friday at Prayagraj (Allahabad) while launching the second phase of River Information System between Patna and Farakka.

IWAI, under Jal Marg Vikas Pariyonjna to make Ganga navigable round the year, has constructed the new navigation lock. The new mechanism will help facilitate Hilsa movement from Hoogly-Bhagirathi-River system to the upstream in river Ganga and vice-versa. The navigational lock being built at Rs 361 crore is scheduled for completion by June.

“Fish often disperse widely over large areas while feeding and spawning. This Hilsa migration will lead to increase in its production in the region. Simultaneously, this will increase the river biodiversity and boost the economy of local fishermen,” a shipping ministry spokesperson said.