New Delhi, Oct 13: How often have we come across studies and surveys tracking the movement of the humble fish to understand their migratory pattern?
While reports of the mammoth blue whale and even wild animals being tagged for research have appeared in journals and talks shows, emulating the study on fish is less heard off.
But one such study is being carried out by the The ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata with an objective to increase the population of Hilsa fish in the Ganges.
This follows a drastic reduction in their numbers especially between Farakka in West Bengal and Prayagraj in Uttar Pradesh since the construction of the Farakka barrage in 1975.
The study began in 2020 and since then 391 live Hilsa fish weighing 250 grams have been tagged and released into the river.
A major breakthrough was achieved on October 6 when a fisherman caught one of the tagged fish live along the banks of the Ganga at Baidybati under Hooghly District, West Bengal, giving the researchers a clear understanding of movement pattern, among other aspects.
The fish was ranched on October 1 at Farakka and during the course of its four days and 21 hours journey, it swam 225 kms.
“Of the 225 Kms of lower stretch of the river, 95 Kms stretch is a freshwater tidal stretch that shows the river stretch experiences tidal current. Negotiating the tidal current, the Hilsa migration speed was estimated as 0.56 m/s. It has also recorded a weight loss of 34 gms during the period of migration,” said ICAR in a statement.
This interesting result is of first its kind to record in the migratory fish species in the country, it said.
The study was a joint initiative of the ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata and the National Mission for Clean Ganga.
Hilsa is a popular delicacy in households across the eastern states, with some estimates suggesting that the demand ranges between 30,000 to 40,000 metric tonnes on an average.
However, dwindling production rate has made this variety an expensive proposition for middle class families.
On September 21, the Bangladesh government allowed traders to export 2080 metric tonnes of Hilsa to West Bengal as part of a goodwill gesture, ahead of the Durga Puja celebrations.