Data from: Ocean warming expands habitat of a rich natural resource and benefits a national economy

Geographic redistribution of living natural resources changes the access and thereby harvesting opportunities between countries. Internationally shared fish resources can be sensitive to shifts in the marine environment and this may have great impact on the economies of countries and regions that rely most heavily on fisheries to provide employment and food supply. Here we present a climate change related biotic expansion of a rich natural resource with substantial economic consequences, namely the appearance of Northeast Atlantic mackerel (Scomber scombrus) in Greenlandic waters. In recent years, the summer temperature has been record high in the Irminger Current and this development has expanded the available and realized mackerel habitat in time and space. Observations in the Irminger Current in East Greenland in 2011 of this temperature sensitive epipelagic fish were the first records so far north-west. This change in migration pattern was followed by a rapid development of a large-scale fishery of substantial importance for the national economy of Greenland (23% of Greenland's export value of all goods in 2014). A pelagic trawl survey was conducted in mid-summer 2014 and the results showed that the bulk of ~1 million tonnes of mackerel in the Irminger Current in SE Greenland were located in the relatively warm (>8.5ºC) surface layer. Mackerel was also observed in SW Greenland. Finally, 15 CMIP5 Earth System Model projections of future marine climate were used to evaluate the epipelagic environment in Greenland. These projections for moderate and high CO2 emission scenarios (RCP 4.5 and 8.5) suggest how the available mackerel habitat may expand further in space and time. Overall, our results indicate that, if the stock remains large, productive and continues its current migration pattern, then climate change has provided Greenland with a new unique opportunity for commercial exploitation. However, positive cases like this should not be cherry-picked and misused as arguments against timely and effective mitigation of climate change.

生物自然资源的地理空间再分布，会改变各国的资源获取路径，进而影响捕捞作业的机遇。国际共享的鱼类资源对海洋环境变化极为敏感，这对于高度依赖渔业保障就业与粮食供应的国家和地区而言，可能会造成严重的经济冲击。本研究聚焦一项与气候变化相关的丰富自然资源的生物扩张现象，其蕴含显著经济影响——即东北大西洋鲭鱼（Northeast Atlantic mackerel，Scomber scombrus）现身格陵兰海域。近年来，伊尔明格海流（Irminger Current）的夏季水温屡创纪录，这一变化使得鲭鱼的适宜栖息空间在时间与空间维度上均得到拓展。2011年，科研人员在格陵兰东部的伊尔明格海流中首次观测到这种对水温敏感的近表层鱼类，这是该鱼种迄今在西北海域的首个观测记录。这种洄游模式的转变，随后催生了规模化捕捞产业，该产业对格陵兰国民经济具有重要意义——2014年其产值占格陵兰所有商品出口总额的23%。2014年仲夏，科研团队开展了中层拖网（pelagic trawl）调查，结果显示，格陵兰东南部伊尔明格海流中约100万吨鲭鱼的主体群体，栖息于水温高于8.5℃的表层水域。研究团队同时在格陵兰西南部海域观测到了鲭鱼群体。最后，本研究采用15个耦合模式比较计划第五阶段（CMIP5）的地球系统模式（Earth System Model）对未来海洋气候的预测结果，评估格陵兰海域的近表层海洋环境。针对中等和高二氧化碳排放情景的典型浓度路径（RCP，Representative Concentration Pathways）4.5与8.5的预测结果显示，鲭鱼的适宜栖息空间有望在时间与空间维度上进一步扩张。总体而言，研究结果表明：若鲭鱼种群规模保持庞大、生产力稳定且维持当前洄游模式，那么气候变化将为格陵兰带来全新的商业化开发机遇。但需注意，此类正面案例不应被选择性撷取并滥用，作为反对及时有效开展气候变化减缓行动的论据。