Nature, extent and causes of post harvest losses in export-oriented giant freshwater prawn (Macrobrachium rosenbergii) market chain in Sri Lanka

Abstract

The GFP (M. rosenbergii) industry in Sri Lanka is vital to rural livelihoods and the national export economy. However, substantial post-harvest losses occur throughout the market chain, from harvest to export. We assessed the extent and causes of these losses for fishers and evaluated handling, grading, storage and transportation practices at each key actor stage of the market chain. GFP is primarily harvested as bycatch in gillnet fisheries that target finfish. Substantial post-harvest losses occur at the producers due to predation, physical damage, molting and delayed retrieval. Predation rates vary widely among reservoirs, reaching as high as 60.1%. Molting rates also contribute to losses, with up to 15.2% recorded at some reservoirs. Post-harvest handling practices are inconsistent; fishers generally did not grade or ice the harvests, while only 50% of local collectors employ adequate icing (with a GFP-to-ice ratio of 2:1 to 3:1), though one third of them use minimal quantities. Central collectors and factory agents adopt better practices by implementing improved grading systems and lowering GFP-to-ice ratios to 1:1. Most of the key actors utilise insulated containers such as Styrofoam or fibre reinforced plastic (FRP) boxes. Transportation durations range from 5 minutes to 6 hours, with rural infrastructure challenges leading to delays, which increases the susceptibility to spoilage. Exporters grade GFP based on weight and quality, primarily for chilled (60%) and frozen products. Poor handling, inadequate icing, prolonged storage and infrastructure limitations contribute to quality degradation and economic loss. This study emphasises the need for improved post-harvest management practices, including standardised grading, proper icing, infrastructure development and capacity development of key market-chain actors to minimise losses and enhance export competitiveness.