Filling the Gap of Overfishing in LCIA: Eco-factors for Global Fish Resources
Creators: name: Stucki, Matthias
name: Keller, Regula
name: Itten, René
name: Eymann, Lea
Publisher: name: ZHAW Zürcher Hochschule für Angewandte Wissenschaften
Year: 2018
Subjects: Environmental impact
LCA
Overfishing
630: Landwirtschaft

description: Introduction: Life cycle assessment has been widely used to measure the environmental impact of food production and value chains. However, there is a lack of LCIA methods to assess the contribution of fish consumption to the global problem of overfishing, despite that fact that more than two thirds of commercially used fish resources are overexploited. Due to this methodological gap, fish is often determined to have a lower environmental footprint than other sources of animal protein in LCA studies. The aim of this publication is to present the development of eco-factors for fish resources and by-catch as an addition to the Swiss Ecological Scarcity Method 2013 and to compare the eco-factors of different fish resources and the impacts of fishing as well as the impacts of dietary alternatives like chicken, pork, lamb, beef and veal.

Materials and Methods: The sustainable use of fish resources ensures that the fish stock for each fish species exceeds the minimum stock needed for a maximum sustainable yield. Therefore, the method developed uses a distance to target approach based on the fish stock for maximum sustainable yield (FSMSY) and the current fish stock (FS) for the characterisation of the use of fish resources. Langlois et al. and Emanuelsson et al. also suggest approaches for the characterisation of overexploitation of fish resources based on the FSMSY. The eco-factors were calculated for each fish species and fishing area. Thereafter, they were aggregated for each fish species using the weighted average of the total catch per fishing area. The target value for FSMSY depends on the fish species and the fishing area. The amount of by-catch was approximated with the dead discard of the walleye pollock (gadus chalcogrammus), which has the highest by-catch rate worldwide. In order to be able to compare the eco-factors for fish resources with the eco-factors of meat production, the factors were corrected from live weight to product weight assuming that the product weight corresponds to 45 % of live weight and that 98 % of the economic value is associated with the final product weight.

Results and Discussion: The inclusion of eco-factors for the overexploitation of fish resources and by-catch shows a relevant contribution to the total environmental impact of fish compared to other impacts resulting from fishing and fish processing.
Depending on the fish species, fish can have significantly higher overall impacts compared with different types of meat. The contribution of the eco-factors for by-catch is minor compared to fish resources but still relevant for the comparison with dietary alternatives. The total contribution of the eco-factors for fish resources exceeds the impacts of the fishery and fish processing.

Conclusions: Distance to target based eco-factors using regionalised data for FS and FSMSY not only follow a comparable underlying approach as suggested in literature but also enable aggregation into a single-score with other environmental impacts. The overexploitation of fish resources is highly variable for different fish species and fishing areas as well as for by-catch, which also requires the consideration of by-catch species and fishing method. When comparing fish to equivalent dietary alternatives like chicken, pork, lamb, beef or veal, consideration of the overexploitation of fish resources results in some fish species exceeding the environmental impact of dietary alternatives. Therefore, overexploitation of fish resources is relevant in the Life Cycle Assessment of fish products in different diets. The suggested approach can be integrated in a full single-score LCIA of meals and is able to reflect the regionalised impacts caused by the overexploitation of fish resources for different species and fishing areas as well as the impacts associated with by-catch and fishing method.