Description of the Study Site: Initially, the study was conducted in the Marine Fisheries & Technology Station, Cox’s Bazar. After developing such indigenous technology, the final model was named as, ‘BFRI Fish Dryer’ was then demonstrated and disseminated to different fish dry-yards in Cox's Bazar areas. Developing the design and construction of Dryer: Emergency Dryer Model: The first model was developed to use in an emergency situation, i.e. to meet the emergency need in the absence of the sunlight. To do this, a long rectangular shaped tunnel was prepared using locally available materials such as sliced wood, pitch board, tin sheet, polythene sheet, tripol etc. The dimension of a single unit of the dryer was 7' x 3.5' x 3.5'. Parallel joining of six units constituted the main drying tunnel of the dryer having an approximate capacity of holding 300 kg raw fish. Several horizontal wooden bars were set in parallel position along the top of the width of the dryer to hang the fish by dual hooks made of hard wire. Transparent Model: In the second instance of the development of a low-cost fish dryer, another model was developed using single layer as well as double layer transparent plastic wavy sheet (plastic tin). The size of a single unit of the second model of the dryer was 18' x 2.5' x 2.5'. Locally available materials such as sliced woods, transparent plastic wavy sheets (plastic tin), etc. were used as the main materials to construct the dryer. Several horizontal wooden bars were set in parallel position along the top of the width of the dryer to hang the fish by dual fishing hooks were used. During the bad weather and at night, an electric heater was used to produce hot air. In all the cases, an electric table fan was used to blow the hot air all the time. BFRI Fish Dryer Model: The third and final version of the transparent model was named as the BFRI Fish Dryer, which was developed. The size of the final version was 18’ x 2.5’ x 2.5’ bifurcated in two units of nine feet each joined together on setting. Two layers of thin (0.20 mm) celluloid were used for better insulation and efficient utilization of heat energy. A system to blow hot air (40-55 0C) inside the tunnel was developed using hot plate and a table fan. A maximum-minimum thermometer was used to monitor and control the temperature. Horizontal wooden bars were set in parallel position along the top of the width of the dryer to hang the fish by dual fishing hooks. All other structural details were remained in the second model. Efficiency Assessment of the three Fish Dryers: The drying performances of the three models, i.e. emergency model, transparent model and BFRI Fish Dryer were assessed using three commercially important fish species (Bombay duck, Silver Pomfret and Ribbon fish). The drying time, temperature, capacity, durability, energy efficiency and incidence of blowfly infestation were also assessed. Physico-chemical Properties Analysis:Organoleptic quality assessment: For the sensory (organoleptic) evaluations, a representative whole samples (20kg) of dried products produced by the BFRI Fish Dryer were taken randomly on a tray and different organoleptic characteristics such as general appearance, flavour, filthiness, scale & gut, texture, wetness and saltiness were assessed. Water reconstitution property: Water reconstitution property, i.e. the percentage of water absorbed by the dried fish was assessed for the product produced by the BFRI Fish Dryer at normal temperature (30oC) up to two hours with 30 minutes intervals. Results in this respect were expressed in terms of percentage of weight of water absorbed by the sample. Proximate composition analysis: Proximate composition analysis, i.e. moisture, ash, lipid and crude protein contents were estimated on wet weight basis and expressed as percentage. The chemical analyses were carried out. Moisture: Moisture content was determined by air drying of a given sample in a thermostat oven at 105 ºC for 24 hours. Crude protein: Crude protein was estimated by the Macro-Kjeldahl method by determining total nitrogen and applying the protein conversion factor of 6.25. Lipid: Lipid content was determined by extracting required quantity of samples with analytical grade acetone for 16 to 18 hours in a ground joint Soxhlet apparatus. The oil obtained by evaporation of the solvent on a steam bath was weighed in a sensitive balance and percent lipid was calculated. Ash: Ash content was determined by complete igniting of the sample in a muffle furnace at a temperature of 550 0C for 6 hours. Benefit-Cost Ratio (BCR) Analysis: The benefit-cost ratio (BCR) was estimated considering both quantitative and qualitative factors related to the benefits and costs and measured exclusively in monetary terms. The following most popular formula to estimate the cost–benefit indicators was used: BCR = PVB/PVC, and PVB – PVC = NB, where, BCR was the benefit cost ratio PVB was the present value of all qualitative & quantitative benefits PVC was the present value of all types of costs, and NB was the net benefit, i.e. the difference between PVB & PVC