Age and growth of southwestern Atlantic wreckfish Polyprion americanus

Abstract

Southwestern Atlantic wreckfish Polyprion americanus (27◦56 S and 34◦52 S) were aged using transverse thin sections of the sagittae otoliths of 390 individuals (44–155 cm TL, total length). The index of average percentage error for independent readings of two readers was 3%, and 10% of the sections were considered illegible. Marginal state assessment of the whole otolith’s margin (n = 406) showed that one opaque band (annulus) is laid down each spring–summer. Supposed daily ring counts confirmed what was thought to be the first annual band. Maximum observed age was 76 years for males and 62 years for females. The von Bertalanffy growth model was significantly different (P < 0.01) between males (L∞ = 109.5 cm, K = 0.084 per year and t0 = −4.69 years) and females (L = 129.5 cm, K = 0.0534 per year and t0 = −6.80 years). The absence of wreckfish below 44 cm TL in the samples and younger than 1.5 years means that this is the minimum size and age of recruitment to the bottom.