Spatio-temporal patterns and environmental controls of small pelagic fish body condition from contrasted Mediterranean areas

•We present a global study of small pelagic fish body condition in the Mediterranean.•Fish body condition strongly declined during last decades in almost all studied areas.•Body condition did not vary in synchrony between areas in the Mediterranean Sea.•Well-marked environmental differences between sub-regions were highlighted.•This decline in the condition may have negative effects on ecosystems and fisheries.