Environmental evaluation of different shrimp farming systems of Bangladesh: A Life Cycle Assessment approach

Abstract

Within the overall agro-based economy of the country, the contribution of shrimp production has been considered to grip excellent promise for creating jobs, earning overseas money and supplying protein. However, a number of issues including environmental aspects of marine shrimp farming in Bangladesh are being important day by day for sustainable trade, as consumers of importing countries are demanding environmentally friendly product. Life cycle assessment (LCA) has been promoted as a good tool for evaluating seafood products. This study was aimed to evaluate overall resource use and environmental impact caused by six shrimp farming systems and to identify hotspots and improvement options. The inventory covered the entire chain from shrimp brood collection to shrimp harvesting at farm, mentioned as "cradle to farm gate". Three functional units based on area (one hectare), weight (one tonne) and calorie content (one KCal) were adopted. Allocation by economic value was applied to allocate environmental burdens in case of multiple outputs. To assess the environmental impact, the last update of the CML impact assessment method was used. Selected impact categories included global warming, acidification and eutrophication. Life cycle inventory (LCI) and life cycle impact assessment (LCIA) results were calculated using CMLCA software (Version 5.2). Based on total score of the studied impact categories Extensive (Shrimp + Fish) had the lowest impact for per ha, KCal and ton shrimp production, whereas Semi intensive (Shrimp) was responsible for highest impact for per hectare shrimp production; Improved extensive (Shrimp + Prawn + Fish), was for per KCal production; and Better Management Practice (Shrimp + Fish) and Modified Traditional Technology (Shrimp + Fish) were for higher impact for per ton of shrimp production. Among different farming stages (viz. fertilization, stocking, feeding and power supply), feeding and fertilization were identified the major contributors for the environmental impacts associated with the different shrimp farming systems. Emphasize on natural feed based shrimp farming along with balanced supplementary feed prepared by environmental friendly ingredients was the major recommendation to increase production addressing both economic and environmental sustainability.