Life cycle assessment (LCA) of two rearing techniques of sea bass (Dicentrarchus labrax)

The aim of the present study is to evaluate the environmental burdens associated with an intensive land based rearing system of sea bass (Dicenrrarchus labrax). Life cycle assessment (LCA) methodology was applied in order to compare two growing facility systems: a traditional raceway (TR) and a cascade raceway (CR). The main goal was to settle reference levels to assess environmental performances and to identify hot spots and possible improvements. The analysis was carried out following the CML2 (2000) impact method using Simapro 7.2 software. The contribution analysis showed that the diet process contributed to the majority of the impacts. The sea bass rearing stage was the main contributor of eutrophication (more than 58% in TR and 52% in CR). The analysis revealed that the major part of the energy consumption was due to rearing phase through water pumping and oxygen injection and production, with 175,000 MJ/tonne and 280,000 MJ/tonne, for TR and CR, respectively. For all the studied impacts, the assessment revealed that CR presented more environmental burden than TR. The major differences between the two farming systems lay in Global Warming Potential GWP and energy use EU. Feed efficiency seems to have a dominant influence on the level of impacts involving diet process. Undoubtedly, the shown difference in the environmental load is the direct result of the relative ability of fish reared in TR to better convert their diet into biomass with a feed conversion ratio of 1.7, compared to 2.1 in CR. There are many options for improving the environmental performance of these aquaculture systems. The most important measure is to increase the feed efficiency through improvements in rearing modes, the diet composition and the optimisation of feeding practices. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.