Life Cycle Assessment of Indoor Recirculating Shrimp Aquaculture System

Abstract

This study analyzed the sustainability and environmental impact of indoor recirculating aquaculture systems (RAS) used for raising shrimp in the U.S. A life cycle analysis (LCA) was performed to evaluate the environmental and energy performance of the system. In the LCA study, the functional unit was 1800 kg fresh shrimp, produced by a commercial-scale recirculating shrimp aquaculture system in the U.S. The life cycle model included the hatchery, recirculating farm, product processing & storage, and transportation stages. The impact assessment method used was Eco-Indicator 95 and the environmental impact categories included global warming potential (GWP), ozone depletion potential (ODP), acidification potential (AP), eutrophication potential (EP), heavy metals (HM), carcinogens, pesticides (PC), summer smog (SS), winter smog (WS) and solid waste (SW). According to the LCA results, shrimp farming accounted for 95% of the life cycle energy use and caused 82-99.6% of the environmental impacts in the life cycle system. A scenario analysis examining transportation, marketing, farm location, and biosolids handling was also conducted. Results were sensitive to farm location and marketing scale while transportation and biosolids handling were much less significant. Reducing the scale of the market reduced environmental impacts due to energy savings in product distribution and storage. Impacts of the local-scale scenario were just 42-87% of those of the national-scale scenario. Farm location was also significant since the energy use and environmental impacts in mainland coastal farms were 30% and 9-37% of those in the inland farms, respectively. With the same culture technique and product distribution, coastal farms were preferable to inland farms in terms of energy savings and pollution reduction. Moreover, compared to culturing shrimp locally in Michigan, buying shrimp from the Southern coast reduced life cycle energy by 70% and reduced pollutant emissions by 86-643% for Michigan consumers. In addition, for American consumers, producing shrimp in this country was recommended, over importing shrimp from Asia. Shrimp production and distribution in the US led to a 15-82% reduction in pollutant emissions. In comparing culture technique, there was a trade-off amongst energy consumption, water use, and environmental impacts with RAS and conventional flow-through farms. The RAS used 70% less water than the conventional system, while the electricity usage in RAS was 1.4 times that of the conventional flow-through system. The RAS produced lower GWP, EP, and ODP impacts while the conventional farm showed better performance in terms of AP impacts.