Resource use analysis of Pangasius aquaculture in the Mekong Delta in Vietnam using Exergetic Life Cycle Assessment

Depletion of marine fish stocks has become a global problem. Aquaculture is seen by many as the best way to meet the growing demand for fish products. The question then arises whether aquaculture is a truly environmentally sustainable alternative. Every type of aquaculture is different, therefore each one merits its own case study. To date, Life Cycle Assessment (LCA) studies have mainly examined Western culture systems, although Asia predominates the world aquaculture production by quantity. In this research, we focus on a vertically integrated Vietnamese top exporter of Pangasius food products in the Mekong Delta. Along with a tremendous expansion of this sector in recent decades, intensification coincided with an increased material and energy demand. Therefore, we focus on resource extraction (from cradle to farm gate), expressed as the Cumulative Exergy Extraction from the Natural Environment (CEENE). Hotspots in resource demand are identified over the life cycle stages (juvenile production, feed production and culturing to marketable-sized fish). The life cycle resource footprint includes mainly land (62%, mainly for feed production), water (31%, mainly for on-site farming of the fish) and fossil fuels (4%, mainly for energy needs throughout the feed supply chain). Main methods for reducing this resource demand should be lowering the feed and water input into the ponds and improving the efficiency of the feed supply chain. Pros and cons of closed-loop water-saving systems are discussed. The feed supply chain plays a key role in improving the resource use efficiency. Vietnamese Pangasius producers should be introduced to life cycle thinking and encouraged to pay attention to the environmental performance of their suppliers across the world. For the last goal, a new metric system to score the Feed Conversion Ratio (FCR), i.e. the CEENE FCR, is introduced here.