File photo of Ilish fish Dhaka Tribune

The move comes 40 years after the barrage was built, blocking the fish from their natural upstream spawning migration path

India has redesigned a navigation lock at the Farakka barrage on the Ganges to ensure the smooth and safe migration of illish during their three-month spawning season.

It will ensure the upstream journey of illish to Allahabad on the Ganges from this monsoon on, after over 40 years, reports the Times of India.

The lock had for long stalled the movement of illish from the salty waters of downstream Bangladesh to sweeter water upstream, particularly during the spawning season.

Bangladesh's national fish illish, gets recognition as a geographical indication (GI) product of the country.

This lock has now been redesigned to ensure the smooth and safe migration of illish shoals during their mating season. A navigation lock is a device used to raise and lower boats and ships between stretches of water on a river.

Inland Waterway Authority of India Vice-Chairman, Pravir Pandey, said the barrage gates will remain open for only eight metres between 1:00am and 5:00am each day, the preferred time when the illish seek passage.

This provision has been made in consultation with ICAR Central Inland Fisheries Research Institute, the Central Water Commission, the Farraka Barrage Project Authority, and the Inland Waterway Authority of India (IWAI), he said.