Age and growth of the sharpsnout seabream Diplodus puntazzo (Cetti, 1777) inhabiting the Canarian archipelago, estimated by reading otoliths and by backcalculation

Abstract

The yearly nature in growth increment formation in the otoliths of Diplodus puntazzo aged 1–10 years from the Canary Islands was validated. Each translucent zone in the otoliths represented an annulus with a year's growth represented by an opaque and its adjacent hyaline zone. Lengths at age were described by the specialised von Bertalanffy growth model (L∞ = 541 mm, k = 0.182 year−1, and t0 = −2.531 years), the Schnute growth model (y1 = 171 mm, y2 = 509 mm, a = 0.022, b = 2.59) and the seasonalised von Bertalanffy growth model (L∞ = 546 mm, k = 0.176 year−1, t0 = −2.21 years, C = 0.712, ts = 0.798). Individuals grow fast during the first year of life, attaining approximately 45% of their maximum length. The body proportional hypothesis and the power length–radius relationship used to backcalculate the growth trajectories showed that the growth backcalculation model could be used to provide reasonable estimates of growth in this species. A power relationship (a = 36.19 and = 1.705) was estimated between the total length and the otolith radius. Backcalculated lengths were similar to those predicted by the growth models. Growth parameters estimated from the backcalculated lengths at age were: L∞ = 508 mm, k = 0.197 year−1, t0 = −1.731 years. Data on length and age used to estimate the parameters of the von Bertalanffy growth model showed that males and females have similar growth rates.