This study was conducted with the financial support of the International Water Management Institute (IWMI), Colombo, Sri Lanka. The authors acknowledge the contribution and support of the staff of the Department of Fisheries and Aquatic Resources, Sri Lanka, other local officials around the country, fishermen, the army personnel during the field visits for the data collection, the reviewers who helped improve the report by providing constructive comments and Samanmalee Thanuja Fernando of Central Environmental Authority, Sri Lanka for painstakingly doing line drawings of maps and the calculations therein under the supervision of Prof. J. Katupotha.