Since the second half of the twentieth century, maritime transport has been characterized by specific dynamics. There has been an unprecedented growth of freight flows, in a context of decolonization, rapid globalization (second wave), and rise of emerging countries through production delocalization. Ports are key players in the global supply chain, as critical nodes at the interface between land and sea. However, disruptions of all kinds can have important repercussions on this supply chain. Maritime networks have reached a high level of optimality and concentration, but also of vulnerability, as global shipping circulations depend more and more on a handful of major hubs. The aim of this paper is to test the network impacts of the global financial crisis (2008-2009), which caused the collapse of the world demand for goods and significant decreases in GDP and maritime traffic volumes, in order to correlate them with those of the COVID-19 pandemic. Historical, daily data on containership movements allow us to trace such impacts with precision, in order to study port traffic dynamics, network topology, and geographical variations. Methods are borrowed from the field of graph theory and complex networks. This analysis contributes to the literature on network criticalities in general, while it also discusses the capacity of ports and maritime networks to recover from a major shock.