Life cycle assessment (LCA) proves that Manila clam farming (Ruditapes philippinarum) is a fully sustainable aquaculture practice and a carbon sink

Abstract

Manila clam (Ruditapes philippinarum, Adams and Reeve, 1850) farming is a quantitatively important and valuable form of aquaculture production worldwide but, to our best knowledge, no life cycle assessments (LCA) have been undertaken on it. However, being a filter feeder and producing a thick shell during the growing cycle, the capacity of Manila clam to remove nutrients, carbon, nitrogen and phosphorous from the marine environment potentially has some positive effects on the environment. This study was performed in the Sacca di Goro lagoon, located in the southernmost part of the Po River Delta, in the northwestern Adriatic Sea. The LCA of clam farming from a cradle-to-gate perspective have been carried out, including the production stages as seed procuring, sowing, harvesting, depuration and packaging to obtain 1 ton of fresh ready-to-sell clams. The results show that area preparation, fuel combustion and plastic bags were the main contributors to the environmental impacts. The potential capability as a carbon sink of 1 ton of clams has been calculated and the effects on eutrophication reduction by fixing nitrogen and phosphorous in shells, with a net sequestration of 444.55 kg of CO2, 1.54 kg of N and 0.31 kg of P per year.