Jadavpur University scientists developing a model to predict Hilsa catch
Marine scientists from Jadavpur University in Kolkata are developing a model to predict how much Hilsa would reach the Bengali platter every year.
“The model will not only tell us how much Hilsa would be available in the rivers and estuaries, but also the sustainable fishing limit. The quantity could vary from year to year depending on various factors such as availability of food (plankton), turbidity, fresh water flow, wind direction, lunar phase and sea surface temperature among others,” said Sugata Hazra, director of School of Oceanographic Studies at Jadavpur University, who is leading the project.
Hilsa is often reckoned as the queen of fishes by Bengalis, most of whom are fanatic about its aroma and taste. The declining availability of hilsa is of great concern to almost all Bengalis in the country that peaks every year during the monsoons.
The obsession is such that chief minister Mamata Banerjee was flooded with requests to persuade Bangladesh Prime Minister Sheikh Hasina to lift the ban on hilsa exports to India that Dhaka imposed in July 2012.
Work on the model is progressing and the JU team hopes to come up with the predictive model sometime later this year.
“We are studying several models including ‘Ecopath with Ecosim’ – a path-breaking model developed by US agency National Oceanic and Atmospheric Administration – which helps scientists to accurately understand complex marine ecosystems. We are trying to come up with a single model which would allow us to predict month-wise and if possible daily availability of hilsa population in the fishing zone,” he added.
Both the catch of hilsa and the size of the fishes had been dwindling over the years. Experts have pointed out various reasons behind this ranging from siltation of rivers, unbridled fishing of juvenile hilsa, pollution, loss of habitat among others. Incidentally before the Farakka barrage was built on the Ganged, hilsa was found in Hardwar too.
According to the government estimates the hilsa catch has come down from 33,102 tonnes in 2000-01 to 9,269 tonnes in 2014-15, a decline of close to 72% percent.
Hyderabad-based Indian National Center for Ocean Information Services (INCOIS) under the ministry of earth sciences sends out advisories to governments and fishermen about availability and congregation of fish shoals in the sea. The JU-model would help scientists to send similar advisories for hilsa to INCOIS and the state government.
Once the model is prepared scientists would feed it with data such as availability of algae, freshwater discharge rate, rainfall, wind direction, lunar period, turbidity, depth of rivers and temperature among other information. This, in turn, would throw up data on fish availability and how much could be netted sustainably.
“If can go for sustainable fishing with bans and restrictions during some months during the year and in the spawning areas, the hilsa population would recover within the next few years,” said Hazra.
The Bangladesh government has already put in place stringent legislation to conserve the Hilsa population. Dozens of fishermen are arrested for fishing baby hisla (below 500 gms) every year. West Bengal is also planning to bring in similar legislation which would help authorities to arrest anyone buying or selling baby hilsa.