Aspects on the demography of Chub Mackerel (Scomber japonicus Houttuyn, 1782) in the Hellenic seas

The main features of the demography of Scomber japonicus in the Hellenic seas were studied during 1996. The dominant size class in the length frequencies of all catches was 190-200 turn. whereas the dominant age class in the samples from the Nor-them Aegean and Saronikos Gulf was the age class 1, and from the Cretan Sea the age class 3. The formation of the new annulus commences in April for age classes I and 2 and in July for the age class 3. The sex ratio in all samples was found to be 1: 1. The von Bertalanffy growth functions showed no statistically significant difference between males and females. The growth parameters from the pooled data were estimated as: L-infinity = 475.96 nun, K = 0.154 yr(-1) and t(0) = -2.177. Scomber japonicus in the Hellenic seas exhibits slower growth rate than that observed in other Mediterranean regions.