Energy efficiency of Norwegian fisheries from 2003 to 2012

Operation of the Norwegian fishing fleet in harsh waters is energy demanding. The large amount of fuel consumption combined with the associated fuel costs, emission taxes, environmental concerns, and emission regulations call for improved energy efficiency within fisheries. This study examined the energy efficiency of the Norwegian fishing fleet from 2003 to 2012. The goal of this study was to determine the important statistical characteristics and to facilitate the development of future strategies to improve fuel efficiency. Data analysis was performed with R programme, an open source software for statistical computing. First, vessels with single gear were explored. Ten fleet segments within the demersal and pelagic fisheries were compared. Energy efficiency varied among the segments. Factory trawlers, with a mean fuel use coefficient of 0.354 kg fuel/kg fish, and coastal seiners, with a mean fuel use coefficient of 0.054-0.058 kg fuel/kg fish, were the least and most energy-efficient segments, respectively. Nevertheless, the energy efficiencies of all of the segments have improved over recent years. The effects of catch per unit of fishing effort, total stock biomass, fish quota, and fuel price on energy efficiency were explored for factory trawlers. Correlations between energy efficiency and these factors were found. Fluctuations in energy efficiency were primarily due to changes in fish abundance and availability. Energy efficiency and fuel price showed the weakest long-term correlation. Little evidence of technological improvements, which affect energy efficiency, was found either. Second, the effect of employing multiple gears was explored. Coastal seiners, conventional vessels, and purse seiners with single gear were compared with corresponding vessels with multiple gears. Employing other gears in addition to seine on coastal seiners rendered them less efficient, as the additional gear (e.g., trawl) was more energy demanding. The opposite was observed for conventional vessels: using more efficient gears (e.g., seine) in combination with the main gear made conventional vessels more energy-efficient. Purse seiners with multiple gears used trawl to catch blue whiting (Micromesistius poutassou); therefore, the efficiency of the trawl was affected by the fluctuations in blue whiting catch and abundance during the years. The energy efficiency of fisheries may be improved by inclusion of energy efficiency in political goals, improvement in fish stocks, better allocation of quotas, and imposition of fuel and emission taxes. Energy efficiency can be further improved by the introduction of energy-saving technologies and alternative fuel systems.