Monitoring Mangrove Loss from Pond Aquaculture Expansion in Asia Using Satellite Earth Observation

Kurzfassung

Mangrove ecosystems are among the most productive and valuable environments on Earth, delivering essential ecological and socio-economic benefits including carbon sequestration, coastal protection, and habitat provision for diverse marine species. However, mangroves face increasing pressures from human activities, with rapid expansion of pond aquaculture emerging as a main driver of mangrove deforestation, especially in Asia, which hosts nearly 40% of the world’s mangroves.

This study presents a comprehensive continental-scale assessment of mangrove loss attributable to aquaculture pond expansion across Asia’s coastal zones, with a focus on Southeast Asia, where mangrove conversion is most severe. Utilizing satellite-based Earth observation data, including an object-based, single-feature inventory of aquaculture pond dynamics derived from Sentinel-1/-2 optical and radar time series and Landsat archive imagery, alongside the Global Mangrove Watch (GMW) dataset, we quantified spatial and temporal relationships between pond presence and mangrove forest decline.

By integrating these datasets within a harmonized time-indexing framework, we directly associate pond activation events with subsequent mangrove decline to attribute deforestation to aquaculture expansion. Our results reveal strong spatial-temporal correlations: aquaculture ponds predominantly cluster in coastal river deltas, overlapping with mangrove loss hotspots, while pond activation frequently coinciding with or directly following significant mangrove loss. Across Asia, mangrove cover declined by approximately 7.2 percent (2,284 km²) in Indonesia and up to 22.2 percent in Pakistan over the study period from 1996-2019. Key hotspots of aquaculture-driven mangrove degradation were identified primarily in Indonesia, Myanmar, and Vietnam, with Indonesia alone accounting for over 13,000 hectares of mangrove loss between 1996 and 2007 due to pond expansion.

Overall, this study underscores the substantial environmental footprint of pond aquaculture on Asia’s coastal ecosystems, demonstrating that aquaculture expansion is a principal driver of mangrove loss in critical regions. By leveraging advanced satellite Earth observation technologies, this research demonstrates the potential of remote sensing data to accurately quantify and monitor mangrove loss at large scales, providing timely, spatially detailed insights into ecosystem changes. Such capabilities are essential for deepening our understanding of the increasing pressures blue carbon ecosystems face from anthropogenic and climatic changes.