Mapping of land-based aquaculture regions in Southeast Asia and its Spatiotemporal change from 1990 to 2020 using time-series remote sensing data

Aquaculture, a crucial component of global food production, faces sustainability challenges due to increased competition for natural resources, environmental pollution, and subpar management practices. Understanding spatial-temporal changes in aquaculture distribution can offer insights into guiding its scientific and sustainable development. While Southeast Asia constitutes a key player in global aquaculture, there exists a significant gap in long-term remote sensing monitoring of aquaculture changes at a sub-continental scale. To fill this gap, this study introduces a workflow for aquaculture extraction that combines both automated and manual methods, based on water and edge frequency detection. By using time series of Landsat images and Sentinel-2 images on the GEE platform, we extracted spatial distribution data of aquaculture in Southeast Asia for five periods from 1990 to 2020. This data, boasting an accuracy exceeding 89.53% and peaking at 95.49%, laid the foundation for investigating the spatial distribution patterns, temporal-spatial changes, and area center changes of aquaculture across the study periods. The results showed that the period of aquaculture rapid expansion was concentrated in the first two decades, followed by a gradual decline in the expansion rate, and a consistent northwestward movement of the area center. The spatial distribution pattern of aquaculture in Southeast Asia gradually changed from "Indonesia and the other producers each account for 40% and 60%" to "Vietnam, Indonesia and the other producers each account for 40%, 30%, and 30%".