DataSheet_3_Reducing the Fuel Use Intensity of Fisheries: Through Efficient Fishing Techniques and Recovered Fish Stocks.csv

Understanding the drivers of greenhouse gas emissions in food production systems is becoming urgent. For wild capture fisheries, fuel use during the fishing phase generally dominates emissions and is highly variable between fisheries. Fuel use is also essential for the economy of the fisheries, but fuel-intensive fisheries can still be profitable due to fuel subsidies, in particular, if the target species is of high value. Developing an innovative bottom-up approach based on detailed catch and spatial fishing effort data, in the absence of direct fuel data, we analysed the fuel use intensity (fuel use per kg landed) and economic efficiency (landing value per litre fuel used) of Danish capture fisheries for the period 2005-2019. An overall decline in fishing effort did not significantly affect the overall fuel use intensity and efficiency, which was stable for most of the fleet segments and marine species. Robust differences in fuel use intensity among individual fisheries, reflected differential spatial accessibility and vulnerability of target species to fishing. In addition, different fishing techniques targeting the same set of species showed differences in fuel use per unit landed. Danish seining and gillnets had a lower fuel use intensity and higher economic efficiency than demersal trawling; and purse seining than pelagic trawling. The variability between stocks and fleets also indicates that there is generally potential for improvement in overall efficiency from improved stock status. Short-term management actions to promote the best available fuel-efficient fishing techniques combined with additional long-term actions to secure the recovery of stocks have the potential to reduce fishery greenhouse gas emissions. Sustainable fisheries and normative environmental management are crucial to developing incentives towards reducing fuel use whenever the fishing sector industry and science work jointly at implementing solutions, as incentives for the industry to reduce fuel use are limited as long as the fishing activity is profitable.

深刻理解食物生产系统中温室气体排放的驱动因素已成为当务之急。对于野生捕捞渔业而言，捕捞阶段期间的燃料消耗通常占主导地位，并在不同渔业之间具有高度的可变性。燃料消耗对于渔业的经济发展同样至关重要，然而，由于燃料补贴的存在，燃料密集型渔业仍能保持盈利，尤其是当目标物种具有高价值时。在缺乏直接燃料数据的情况下，我们基于详细的捕捞量和空间捕捞强度数据，采用自下而上的创新方法，分析了2005-2019年间丹麦捕捞渔业的燃料使用强度（每千克上岸的燃料使用量）和经济效率（每升燃料使用的上岸价值）。总体捕捞强度的下降并未显著影响整体的燃料使用强度和效率，对于大多数船队段和海洋物种而言，这些指标均保持稳定。不同渔业之间燃料使用强度的稳健差异反映了目标物种对捕捞的空间可及性和易受伤害性的差异。此外，针对同一物种组的不同捕捞技术也显示出每单位上岸燃料使用量的差异。丹麦的拖网和刺网捕捞在燃料使用强度上较低，而在经济效率上较高，与底层拖网相比；与上层拖网相比，则 purse seining（围网捕捞）表现更优。不同种群和船队的可变性也表明，通过改善种群状况，通常存在提高整体效率的潜力。短期管理措施旨在推广最有效的节能捕捞技术，并结合长期措施以确保种群恢复，这些措施有望减少渔业温室气体排放。可持续渔业和规范性的环境管理对于推动减少燃料使用的激励机制至关重要，只要捕捞活动有利可图，行业减少燃料使用的激励措施就有限，而行业与科学界共同实施解决方案，则有望促进这种激励机制的发展。