Demographic structure and distribution of John Dory, Zeus faber L. 1758, in the Adriatic Sea

Abstract

Summary Recent demographic structure and distribution of the fish species Zeus faber in the Adriatic Sea were investigated in this study and compared with a 1948–1949 study. The presence of John Dory in the Adriatic Sea was recorded at a depth range from 21 to 239 m, with the highest biomass indices at depths between 50 and 100 m. The length frequency distribution, length–weight relationships, sex ratio and length at first sexual maturity were determined. Results based on data from the 1948– 1949 Hvar expedition and the MEDITS surveys of 1996–1998 showed in the 50-year interval that the index of biomass and area of distribution of this species in the Adriatic Sea have been reduced and that the demographic structure of the population has changed. Negative changes described in the paper indicate an overfishing of the Z. faber species in the Adriatic Sea.