Age, growth and mortality of the starry weever Trachinus radiatus Cuvier, 1829 in the Tunisian waters

Age, growth and mortality of the Starry weever Trachinus radiatus were studied for the first time from 214 individuals collected in the Gulf of Tunis between February 2014 and January 2016. The significant relationship between length-weight was observed for males (a = 0.011, b = 2.992, R-2 = 0.981, n = 77) and females (a = 0.010, b = 3.036, R-2 = 0.957, n = 109). Age was estimated by the observation of otoliths transverse thin sections. Age of individuals ranged from 1 to 15 years. The precision was measured by two age estimations from two experts and indicated a good agreement between them (PA = 85.6%, CV = 3.8% and IAPE = 4.1%). The growth parameters of the von Bertalanffy model were TL infinity = 38.41 cm, W-infinity = 507.47 g, K = 0.3396 year(-1), t(0) = 0 year for males and TL infinity = 45.46 cm, W-infinity = 914.04 g, K = 0.2136 year(-1), t(0 )= 0 year for females. Age at first sexual maturity (t(m)) of T. radiatus was 3.5 years, while the age at optimum length (t(opt)) was 6.6 years. The natural mortality (M), total mortality (Z), fishing mortality (F) and exploitation (E) rates were respectively M = 0.429 yr(-1), Z = 0.453 yr(-1), F = 0.024 yr(-1) and E = 0.053.