CARACTERÍSTICAS CLIMÁTICAS

In the fish supply chain system, shown in Figure 2.2, a certain amount of energy is used before the fish is served on the table. The energy consumed will depend on the type of processes involved in the chain (Thrane, 2004b). Even though in some cases fish processing can be more energy intensive than fishing, most researchers agree that the fishing stage itself consumes significant amounts of fuel (Eyjólfsdóttir et al., 2003; Ziegler et al., 2003; Thrane, 2004b; Hospido et al., 2006; Muir, 2015); therefore, despite the fact that it will not provide a complete assessment, focusing this study on energy consumption during the fishing stage will give relevant calculations on particular fishery production chains.

Globally, fuel consumption on fishing activities, in terms of litres (l) of fuel per ton (t) of fish production, constituted 620 litres/ton in 2000 and accounted for 1.2% of global fuel consumption (Tyedmers, 2005). Based on the average calculation of fuel use since 1990, energy intensity displayed an increasing trend to 639 litres/ton (Parker and Tyedmers, 2015). Compared to other protein sources, the amount of energy spent on fishing is relatively high, however, the special characteristics of nutrition which is only found in fish, such as vitamin B12, balanced amino acid, low cholesterol, saturated fat and calories, and high polyunsaturated fat and fatty acid, has made fish an extremely important food source (Sheeshka and Murkin, 2002; Tilami and Sampels, 2017). Therefore, the fact that this exploitation of marine resources is exceedingly dependent on fossil fuel requires action to control the energy input as well as preserve the natural resources.

Historically, the concern related to energy in fishing started when it was observed that the increase in fishing effort was not proportional to increase fish production. Global fish production during the 1950s and 60s increased by 150%, identifying the sea as a promising food source for the future. Encouraged by low fuel prices, excessive fishing efforts continued into the 1970s. However, the increasing amount of fuel spent on fishing was not followed by comparable increase in fish production. The significant increase in the fuel price in the 1980s and signs of overfishing in some areas aggravated the situation and raised awareness with respect to energy efficient fishing.

To date, research related to energy use in fishing has typically focused on three topics: energy audits on individual vessels and fleets, fuel input assessment, and life cycle assessment (LCA) (Parker and Tyedmers, 2015). Energy audits aim to discover best

energy saving practices by identifying the amount of energy supplied to the vessel and its application in the fishing process, including the components of the fishing vessels (Thomas et al., 2010; Basurko et al., 2012). An energy audit has different levels with each affecting the accuracy of the result and the recommendations. For example, According to the Australian Standard for Energy Audit, the audit is divided into 3 levels: 1, 2 and 3 (Australian/New Zealand Standard, 2000). Level 1 calculates the general energy consumption, Level 2 identifies the consumption and application pattern on the fishing vessels as well as hot spots for potential savings (Basurko et al., 2013), whereas Level 3 focuses on the improvement of identified hotspots (Parente et al., 2008). Collaboration with fishers plays a significant role in the energy audit, especially when conducting the audit level 2 and 3, as the fishers are involved in the data collection and analysis (Johnson, 2014).

Fuel input assessment, which is basically energy audit Level 1, associates calculating the energy use in particular fisheries with identifying potential saving practices in general. The study would investigate the level of energy use by comparing it with the available benchmark. Analysis on fuel input is commonly presented in FUI which refers to the amount of fuel required to produce a certain quantity of seafood product (Tyedmers, 2004). Additionally, as part of the food production system, ep-EROI is used when undertaking a comparison with other food products. This dimensionless ratio was calculated by dividing the amount of edible protein yielded from the food to the energy required to produce the food (Tyedmers, 2004). The scope of a study might vary at national (Thrane, 2004a; Schau et al., 2009), regional and global levels (Tyedmers, 2005; Parker and Tyedmers, 2015). Geographically, very little research has been conducted in developing countries, with prolific research having been conducted in industrialised nations, such as Japan, Spain, America, Australia and the Scandinavian countries. However, data from the FAO (2007), shows that when compared to industrialised countries, developing countries consumed a significant amount of fuel.

Energy input on a fishing vessel can be divided into direct and indirect inputs (Tyedmers, 2004). Fuel input assessment is commonly related to direct inputs, i.e. fuel used during the fishing process. Indirect inputs are associated with the energy required to obtain the production factors, for instance, vessels, fuel, ice and fishing gear as well as for maintenance of capital goods. A study involving indirect inputs is typically found in the LCA research which has been receiving more attention since the early 2000s (Vázquez- Rowe et al., 2012), and which is not only limited to the fishing stage (Hospido and

Tyedmers, 2005; Schau, 2012) but also considers the pre and post-harvest stages (Eyjólfsdóttir et al., 2003; Thrane, 2004b). LCA research on fisheries is also centred on developed countries, nevertheless studies have evolved from only a few fisheries to diverse species, fishing vessels and fishing gear (Vázquez-Rowe et al., 2012).

Studies related to energy use in fisheries are facing several common issues including data availability, methodology and implementation strategies. Whilst small-scale fisheries are mostly struggling with data gathering in general (Parker and Tyedmers, 2015), large-scale fisheries are hampered by data adequacy regarding longer time series analysis and detailed elements such as discard and bait (Vázquez-Rowe et al., 2012). Furthermore, the complexity and diversity of fishing practices (Charles, 2001) in addition to the wide- ranging environmental impact indicators associated with energy use (International Organisation for Standardisation (ISO), 2006a) have resulted in variations in scopes, goals, system boundaries and methods. Therefore, energy use in fisheries is an extremely specific study whose implementation will only be suitable for the intended scope. In addition, researchers have been more encouraged recently to consider the socio-economic aspects when dealing with implementation proposals (Vázquez-Rowe et al., 2012). In this study, both direct and indirect energy inputs will be included in the impact assessment. Direct inputs are calculated from fuel consumption and presented in FUI per kg catch, FUI per £ revenue and ep-EROI. Meanwhile, indirect inputs are measured from resources used throughout the fishing vessel lifetime.