State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, China; School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, China; State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, China; Shenzhen Municipal Engineering Lab of Environmental IoT Technologies, Southern University of Science and Technology, Shenzhen, Guangdong Province, China.
Sci Total Environ. 2019 Oct 20;688:1286-1297. doi: 10.1016/j.scitotenv.2019.06.179. Epub 2019 Jun 13.
Enclosure fisheries have accommodated the widespread expansion of aquaculture in many lakes throughout the Yangtze Plain (YP), China, for over four decades. Such practices have increased food provision but have also triggered various detrimental environmental consequences. To restore ecosystem functions, the Chinese government recently implemented specific regulations to remove enclosure fences from lakes throughout the YP. However, little information is available on the spatial and temporal distributions of the enclosure fences, particularly in relation to the enforcement of recent policy changes. Using synthetic aperture radar (SAR) satellite images taken between 2002 and 2018, we conducted the first comprehensive assessment of the interannual changes in enclosure fences in 17 large lakes throughout the YP. Consistent decreases in fence density were found in most lakes after 2015; 15 lakes had >50% of their fences removed, while 9 lakes had >90% removed. The timing and implementation of the development and destruction of enclosure fisheries were related to government policy; before 2015, regional dynamics in enclosure fisheries were attributed to provincial policies, whereas the nearly ubiquitous fence demolition after 2015 was likely a response to national policy. This study represents remotely sensed evidence that demonstrates the importance of both local and national environmental policies and their effectiveness in mitigating ongoing human impacts on vulnerable and valuable natural resources. These findings provide valuable baseline information for future lake environmental monitoring and restoration in the YP region, and the methods used here could be applied to other lacustrine and coastal regions experiencing similar aquaculture activities.
围网养殖在过去四十多年中在中国长江中下游平原（YP）的许多湖泊中得到了广泛的发展。这些做法增加了食物供应，但也引发了各种不利的环境后果。为了恢复生态系统功能，中国政府最近实施了具体的规定，要求拆除 YP 各湖泊的围网。然而，关于围网的时空分布的信息很少，特别是在最近政策变化的执行方面。本研究利用 2002 年至 2018 年期间拍摄的合成孔径雷达（SAR）卫星图像，首次全面评估了 YP 17 个大型湖泊中围网的年际变化。结果发现，2015 年后，大多数湖泊的围网密度持续下降；15 个湖泊的围网减少了 50%以上，9 个湖泊的围网减少了 90%以上。围网渔业的发展和破坏的时间和实施与政府政策有关；2015 年以前，围网渔业的区域动态归因于省级政策，而 2015 年后几乎无处不在的围网拆除可能是对国家政策的响应。这项研究提供了遥感证据，证明了地方和国家环境政策的重要性及其在减轻人类对脆弱和宝贵自然资源的持续影响方面的有效性。这些发现为 YP 地区未来的湖泊环境监测和恢复提供了有价值的基线信息，并且这里使用的方法可以应用于其他经历类似水产养殖活动的湖泊和沿海地区。
