Solar activity governs abundance of Atlantic Iberian sardine Sardina pilchardus

Annual sardine Sardina pilchardus landings from 1906 to 2002 off the northwest coast of the Iberian Peninsula vary according to solar activity.When the solar cycle is short, there is a trend towards increasing water transport onshore, which favours larval retention in areas close to the coast and, hence, sardine catches increase.However, when the solar cycle is longer, the trend is toward increasing water transport offshore, carrying eggs and larvae into areas where there is not enough food to survive and, therefore, decreasing sardine catches.These findings reveal the potential importance of solar activity on all biological process affected by coastal upwelling, including pelagic fisheries.