Age and growth of the annular seabream, Diplodus annularis (Pisces: Sparidae), from the Canarian archipelago (central-east Atlantic)

Abstract

Age and growth of the annular seabream Diplodus annularis off the Canary Islands (Central-east Atlantic) were studied. The length range of fish was between 82 and 209 mm in total length. Otoliths showed clear growth rings. Two rings, one opaque and one translucent, were laid down each year on the otoliths. Seasonal growth cycles were related to physiological changes produced by the influence of temperature and reproductive cycle.The opaque ring was deposited during the summer months and the translucent one during the winter months. Individuals aged 0 to 6 years were found. After the first year, the annual growth rate droped rapidly as a consequence of the sexual maturity. The difference in size between males and females was not considered as evidence of an intersexual difference in growth rates since they are the same specimens at different stages of sexual succession. The parameters of the von Bertalanffy growth equation for all individuals were: L_∞ = 248.5 mm, k = 0.259 year^–1, and t₀ = –0.871 year. The backcalculation method demonstrated the validity of using otoliths for estimating age and growth.