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PARALLEL SESSION 6B: FISHIERIES, SOIL, AND EMERGY METHODS 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
Overfishing, overfishedness and wasted potential yield: new impact
categories for biotic resources in LCA
Andreas Emanuelsson 1,2,* , Friederike Ziegler 1 , Leif Pihl 2 , Mattias Sköld 3 , Ulf Sonesson 1
1SIK – The Swedish Institute for Food and Biotechnology, Department of Sustainable Food Production, 402
29 Gothenburg, Sweden
2University of Gothenburg, Department of Biological and Environmental Science, 451 78 Fiskebäckskil,
Sweden
3Swedish University of Agricultural Sciences, Department of Aquatic Resources, Institute of Marine Research
453 30 Lysekil, Sweden
Corresponding author. E-mail: ae@sik.se
ABSTRACT
Overfishing is one of the largest environmental challenges that mankind face, since it’s the largest driver for marine biodiversity loss
on planet that to two thirds consist of oceans and directly limits a biotic resource of high nutritional and cultural value. Yet it has not
been directly incorporated in LCA methodology which restricts a holistic scope of any Seafood LCA. We propose Wasted Potential
Yield as a midpoint impact category to fill this gap, complemented with two sub impact categories explaining the main contributing
mechanisms: F-Overfishing and B-Overfishedness. Characterisation methods relate to the Maximum Sustainable Yield concept that
has been reinstated as a management goal for the European Union with full implantation deadline to 2015, after the ratification of
Johannesburg Plan of Implementations and the United Nations Convention on the Law of the Sea. Characterisation factors were
obtained for 43 European commercial stocks regarding 13 species between 2000-2010, which covered approximately half of European
catches and 7% of the global catches, i.e. most of the commercially important stocks in the North East Atlantic. Due to typically
high variation in fishery production system, we stress the need for both database aggregated characterisation factors and routines for
continuous data collection by the LCA practitioner to minimize spatial and temporal error of representativeness.
Keywords: fisheries, impact assessment, seafood LCA, maximum sustainable yield, overfishing
1. Background
Global marine fish catches have stabilised around 80 million tons per year during the last decade (FAO
2012), although the global effort spent to catch fish has steadily increased since the seventies (Anticamara et
al., 2011). Fishing fleets have expanded towards deeper and more remote fishing locations (Swartz et al.,
2010) and the margins of profitability have steadily decreased (FAO 2008). This has been widely interpreted
as the result of overfishing fish stocks, that are spatially or temporally separated in their reproduction and
depend on their own stock size and structure for and growth (Pauly et al., 2002; Myers and Worm 2003;
Mullon et al., 2005; Worm et al., 2009; Froese and Proelß 2010; FAO 2012). Contrary to earlier beliefs
many fish stocks do not quickly recover when fishing pressure decreased once depleted or degraded
(Hutchings and Reynolds 2004). One of the reasons is that high fishing pressure typically alters the age
structure within the stock leaving younger individuals that are less efficient in reproducing (Jennings et al.,
2001). As fisheries exploit the top predators of the ecosystem, the entire ecosystem will be impacted by trophic
cascade effects (Frank et al., 2005). Both coastal and offshore fishing pressure has been shown to induce
trophical shifts, from which a restoration to previous state is unlikely even if fishing pressure decreased
(Scheffer et al., 2001; Jackson et al., 2001). The present extinction rate and loss of biodiversity has been
considered the worst exceeding of planetary boundaries by humans (Rockstrom et al., 2009) and the Millennium
Ecosystem Assessment established overfishing as the dominant direct driver for losses in marine ecosystems
(in contrast to habitat change for most terrestrial system) (MEA 2005), thus the pursuit of a few
commercial stocks indirectly effect the rest of the ecosystem. But overfishing is also directly limiting a biotic
resources that today accounts for 17% of the animal protein intake worldwide, with high nutritional and economical
values that are crucial for many low income and food deficient countries (FAO 2012). Fish as a
product can also replace potential market shares of other environmentally costly food supplies such as beef
(Winther et al., 2009). In economic terms the global fishery systems are sub-optimized, leaving many fisheries
with low profitability due to low stock sizes and overcapacity. If the stocks restored to larger biomasses
and then exploited with equaling catches the global profits has been estimated to increase with 50 billion $
annually equaling more than half of the value of existing landings (FAO 2008). However, such global generalisations
are crude, but probably also underestimated rather than overestimated (Holt 2009).
Life Cycle Assessment (LCA) is an acknowledged and standardized method to assess potential impacts or
damage related to a product or process (ISO 2006a, 2006b). The European Union has concluded that it provides
the best framework for assessing the potential environmental impacts of products currently available
(EC 2003). One of the benefits is the ability to compare and relate products with either potential impacts in
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