For a panel of 109 coastal countries, we show that negative economic shocks in the fisheries sector are associated with an increase in maritime piracy. Our identification strategy uses the variation in the phytoplankton abundance off the individual countries' coasts, measured by satellite data, as a source of such shocks. We find that plankton abundance is positively related to fish catches, but negatively associated with the incidence of piracy, the onset of piracy and the absolute number of pirate attacks. Our instrumental variable estimates indicate that a plankton shock that induces fish capture production to decrease by 10% increases the risk of piracy occurring by 10 percentage points. Similarly, a shock of the same magnitude increases the number of piracy attacks by 8.6%.