Population study of the protected bivalve Pinna nobilis (Linnaeus, 1758) in Thermaikos Gulf (North Aegean Sea) SOFIA GALINOU-MITSOUDI*, GEORGE VLAHAVAS and OLGA PAPOUTSI Alexander Technological Educational Institution of Thessaloniki, Department of Fisheries & Aquaculture Technology, Campus of Nea Moudania, 632 00 Nea Moudania, Chalkidiki, Greece Abstract The population structure and the age and growth of the protected bivalve Pinna nobilis were studied in the Thermaikos Gulf (North Aegean Sea). The density was 1.04±0.17 ind m-2, the highest reported until now in the Mediterranean Sea. Mean length was 34.35±11.78 cm and maximum length (Lmax) was 69.10 cm, which indicated an undisturbed natural population. Allometric relations between morphometric and/or weight parameters were calculated and they indicated that P. nobilis has the priority to ensure the living space for its body growth and protection. Length frequency distribution and the observed age structure indicated that the P. nobilis population studied was constructed mainly of small and medium sized/aged individuals. In comparison with other Mediterranean populations of P. nobilis, the growth rate of the East Thermaikos population was among the smallest ones (k = 0.063), while the maximum length (L∞ = 73.77) was among the largest ones.   < back .