Life-history traits of Chloroscombrus chrysurus (Actinopterygii: Perciformes: Carangidae) in tropical waters of the Atlantic Ocean

Abstract

Background. In fishery biology, information on life-history traits is extremely useful for species conservation and the monitoring, management and sustaining of fish stocks. Nevertheless, detailed biological information is very limited for tropical fishes, especially for those with low economic value, such the Atlantic bumper, Chloroscombrus chrysurus (Linnaeus, 1766). This species is commonly captured by artisanal fisheries in tropical waters and the lack of information makes difficult the development of strategies for the proper management of the species. Therefore, the presently reported study intended to provide new data on the biological parameters of C. chrysurus to fill the gap in the existing knowledge. Materials and methods. Life-history traits of the Atlantic bumper, C. chrysurus, were estimated from 335 fish collected in a western Atlantic region during fishery surveys carried out between 2010 and 2012. Age and growth were determined by annuli counts of sagittal otoliths. Growth parameters were calculated by adjusting the back-calculated length-per-age to the von Bertalanffy growth model. Empirical equations and data on maturity were used to estimate the size and age at first maturity, as well as the optimum size and age. Theoretical longevity and natural mortality were also estimated for the species. Results. Six age classes were identified and asymptotic length (L∞), growth rate (k), and the theoretical age when the specimen was at zero length (t0) and for the whole population those parameters assumed the following values: L∞ = 25.49 cm, k = 0.33 year–1, and t0 = 0.058 years. No evidence of sexual size dimorphism was found, with no significant differences in growth characteristics and in the length frequency distribution between sexes. The principal vital parameters were as follows: size (L50 = 15.8 cm) and age (T50 = 2.9+) at sexual maturity, optimum length (Lopt = 13.08 cm), and optimum age (Topt = 2.1+), as well as its theoretical longevity (A0.95 = 9.17) and natural mortality (M = 0.92) Conclusion. The determined size and age at sexual maturity, optimum length and age, theoretical longevity, and natural mortality indicate that the studied population of C. chrysurus is overexploited. The Atlantic bumper is vulnerable to fishing pressure and should be managed with caution.

Keywords

• age determination
• fish growth
• longevity
• natural