Rapid expansion of coastal aquaculture ponds in China from Landsat observations during 1984–2016

Abstract

Aquaculture is one of the fastest growing animal food production sectors mainly developed in fertile coastal areas. Monitoring and mapping of aquaculture ponds are of utmost importance for the sustainable management of coastal ecosystems. In this study, an integrated updating and object-based classification approach was developed to generate maps of coastal aquaculture ponds in China from 1984 to 2016 at 30-m spatial resolution. The current extent and change of coastal aquaculture ponds in China were analyzed over the course of 32 years. In addition, spatial-temporal dynamics of coastal aquaculture ponds were examined by buffer and overlay analyses. The results showed that the total area of coastal aquaculture ponds in China expanded by 10,463 km2, with the largest gain occurring from 1990 to 2000 (4,207 km2). The coastal provinces of Guangdong, Shandong, Jiangsu, Liaoning, and Hebei had significant increases of aquaculture ponds areas, accounting for 83% of totally expanded ponds in the coastal zone of China. Rapid expansion of coastal aquaculture ponds was observed in the 0–10 km inshore buffer and the loss of wetlands and arable land contributed more than 50% to the expansion. Socio-economic factors helped drive the continual increase of coastal aquaculture ponds in China. Scientific environmental regulations and planning and management strategies at the national and international policy levels should be enhanced to consider the ecological impacts of aquaculture expansion.