Bhubaneswar: Catch of hilsa, one of the most sought-after fishes, has dwindled drastically over the years, forcing the Chilika Development Authority to undertake a research to ascertain the reason behind it and conserve the fish.

According to official data, the annual landing of hilsa in the lake had been 311 tonnes in 1954, which dwindled to 10.51 tonnes during 2016-17. While the average annual landing of hilsa stood at 95.17 tonnes between 1985-86 and 2000-01, it decreased to 46.15 tonnes between 2001-02 and 2016-17.

The authority has also sought help from the Central Inland Fisheries Research Institute in Bengal. The institute had earlier undertaken a research on the Chilika lagoon between 2011 and 2017. "There will be a detailed study on the genetic characterisation of Chilika hilsa, along with the reason behind depletion of stock. After the study, further action will be initiated to conserve the fish," said the authority's additional chief executive Sasmita Lenka.

Authority officials said the probable factors responsible for depletion of hilsa in the lake included extensive use of fishing nets affecting the fish's migration from the sea during monsoon and winter, heavy siltation in the Daya river which empties into the lake and over exploitation during the breeding season.

The hilsa fish is primarily caught from the coast of Bhadrak, Balasore, Puri and Paradip coast in the state. The fish caught from the Balasore cost is of high demand. "The major factors such as hydrological, metrological and ecological ones will be studied to ascertain the cause. The study will also include comparison of hilsa fish of the lake with that from other coasts in the state. Fish samples will be collected from 14 sampling stations in the lake. The research will be completed by June 2020," said Lenka.

Around two lakh people depend on fishing in the lake spread over 1,100sqkm in three districts of Khurda, Puri and Ganjam. The annual catch from the lake has been around 12,140 tonnes. The institute's recent research had revealed presence of 335 species of fishes in the lake, which has been designated as a Ramsar site (wetland of international importance).