Age and growth of the Acoupa Weakfish (Cynoscion acoupa) of the Brazilian Amazonian Coast, through micro and macrostructures in otoliths

Abstract

The aim of the present study was to estimate age and growth of Cynoscion acoupa, using micro and macrostructures in otoliths and length frequency, in a sample of 255 specimens (13–107 cm in total length - TL) collected on the coast of the Maranhão State between 2007 and 2008. Validation of microstructures using alizarin dyes demonstrated daily deposition of microstructures whereas macrostructures were validated as annual according to monthly marginal increment analysis. A zone of daily microstructures from the core was observed in the otolith until 328 days (0.87 year) and after this zone, the first annual macrostructure was formed. There were no significant differences between growth of males and females using the von Bertalanffy model (VBGM), resulting in k = 0.13, L∞ = 142.95 cm TL and t0 = −0.45 year, with ages ranged from 0.3 to 10.2 years. The growth coefficient estimated by LFA was very high (k = 0.28). The results indicated that C. acoupa from the coast of Maranhão has a slow to moderate growth and high longevity, being able to exceed 14 years. Therefore, these parameters are important to understand the population dynamics, and should be considered to define management measures for C. acoupa.