The Hilsa ilisha constitutes the largest single-species fishery of Bangladesh. It accounts for about 30% of the country’s total fish production; the fishery employs more than 1.5 million people.

At the request of the Bangladesh Government the BOBP’s project “Marine Fishery Resources Management in the Bay of Bengal” conducted a series of investigations on the Hilsa ilisha during 1985-86. As a first step, current literature on the biology and fishery of Hilsa ilisha in the Upper Bay of Bengal was reviewed and published in October 1985 as BOBP/WP/37.

The Hilsa investigations covered marine, estuarine and riverine environments; the main areas of investigation were catch statistics, biological studies, racial studies and experimental fishing. Four sampling stations were selected for the investigation, Chittagong and Cox’s Bazar being the marine stations. Five biologists were trained in the programme, and the data obtained were processed later at a training session in Colombo.

This paper sets out the results of the investigations, which were conducted under the overall supervision of BOBP’s Senior Fishery Biologist, Dr. K. Sivasubramaniam.

A consultant, Dr. B.T. Antony Raja, reviewed literature on the subject, trained national biologists, helped them to prepare the Annexures found in this report, and in general monitored the programme. Mr. J. Hertel Wulff (BOBP Biologist - Associate Professional Officer), stationed at Chittagong, assisted the national biologists and processed the data using the micro computer Apple Ile. Mr. M.Van der Knaap (Biologist - Associate Professional Officer) and Mr. T. Nishida (Statistician - Associate Professional Officer) also helped the five Bangladesh biologists- Mr. M. Hossain, Mr. N. N. Das, Mr. Sujjat Al Azad, Mr. Q. Mahbubul Huq and Mr. M. Serajul Islam-to process the data.