Context-dependent changes in maritime traffic activity during the first year of the COVID-19 pandemic

Rapid implementation of human mobility restrictions during the COVID-19 pandemic dramatically reduced maritime activity in early 2020. But where and when activity rebounded, or remained low, during the full extent of 2020 restrictions remains unclear. Using global high-resolution datasets, we reveal a surprising degree of complexity in maritime activity patterns during 2020, yielding a more nuanced picture of how restrictions affected activity. Overall, shipping activity in Exclusive Economic Zones decreased (1.35 %), as expected, however high-seas activity increased (0.28 %). While these annual changes appear modest, there were striking spatially and temporally asynchronous variations in different vessel types' activity in the second half of 2020, ranging from an > 80 % sustained reduction in passenger vessel activity to a 150 % increase in fishing activity. Results suggest systems-level responses were highly context-dependent, pinpointing areas that experienced significant reductions and spikes in activity, and providing hitherto missing details of COVID-19 impacts on economic and environmental sustainability.