Life cycle environmental impacts of Spanish tuna fisheries

The environmental impacts of fishing go well beyond their direct effect on targeted stocks and associated ecosystem components and functions. Here we employ life cycle assessment (LCA) to quantify the scale and importance of emissions that result from the range of industrial activities associated with contemporary Spanish purse seine fisheries for Skipjack (Katsuwonus pelamis) and Yellowfin (Thunnus albacares) tunas. Our analysis encompassed operational inputs to fishing activities along with major inputs to vessel construction and maintenance and post-harvest transport of carcasses to ports in Galicia, Spain. Data were acquired from fishing operations based in each of the Atlantic, Indian and Pacific Oceans, permitting the characterization of both average and basin of origin-specific environmental impacts. Our results indicate that the production and use of diesel fuel while fishing accounts for more than half of the total impacts in six of the seven impact categories analyzed. After fuel inputs, post-harvest transport of carcasses made substantial contributions to each of the environmental dimensions evaluated. In contrast, the use of anti-fouling paint only made a substantial contribution to marine eco-toxicity potential. Comparing the performance of fisheries in the three oceans, Pacific-based operations resulted in the highest emissions across all impact categories modelled. This was largely the result of markedly higher fuel consumption rates together with relatively long post-harvest transport distances. Finally, we modelled two scenarios to quantify the environmental benefits associated with improving tuna abundance and availability. In doing so, we found that efforts to rebuild stocks, particularly in the Atlantic Ocean would not only help reverse the decline of aquatic ecosystems but could result in improvements in the environmental performance of the Spanish tuna fishery.