Silchar: A recent study has found that the depth of the Son Beel, one of the largest lakes in south Assam, has decreased substantially over the years.

The team that conducted the study comprised Manabendra Dutta Choudhury, a professor in the department of life sciences, Assam University, Mriganka Purkayastha, an alumnus of Gauhati University, Sumanta Das, an official of the Silchar fisheries department and resident of the area and another resident, Mriganka Dutta Choudhury.

Son Beel, the second largest wetland in Asia, covers three constituencies - South Karimganj, Ratabari and Badarpur in Karimganj district. It is around 65km from Silchar. Fishes like rohu, chital, boal, mrigal, pabda, rani and khailsha are found here.

Das told The Telegraph on Sunday that according to the study, the reason behind the decrease in depth was the deposition of soil/clay from the Singla, a river that passes through the lake.

He said the lake was one of the vital spots of fish production in the district. However, the production had lessened in the past few years. It was suspected that unscientific methods of fishing and use of pesticides in agricultural lands are the reasons.

"Fishes are often caught in the immature/embryonic stage, which impacts the production. Pesticides used in lands near the lake mix with the river and with the lake water, affecting the fishes/fingerlings," he said.

The width of the lake has also reduced at a few locations, the study said.

Mriganka Dutta Choudhury said the lake can be useful for fish farming, agriculture and tourism and play a significant role in boosting the economic scenario in the district. Some residents said the lake needs dredging and other treatment or it will become a part of history. They urged the government and authorities to take steps to develop it.

Other residents have expressed dissatisfaction over the exclusion of Son Beel in connection with the Namami Barak fest from November 18 to 20.

MLA Kamalakhya Dey Purkayastha said he, during a meeting in Dispur, had proposed that there should be at least an event organised in Son Beel. However, the proposal was not accepted.

Assam fisheries minister Parimal Suklabaidya today said the fisheries department was conducting a study on Son Beel to assess its condition. He said a proposal would be sent to the state government after the study is completed.