Age and growth of three endemic threatened guitarfishes Pseudobatos horkelii, P. percellens and Zapteryx brevirostris in the western South Atlantic Ocean

The age and growth of three endemic threatened guitarfish species were analysed using vertebrae of Pseudobatos horkelii, P. percellens and Zapteryx brevirostris. Edge and marginal-increment analyses were used to evaluate the periodicity of the formation of the band-pairs, suggesting deposition of one band-pair per year, from late winter to late spring. The von Bertalanffy growth model was used to describe the growth of these species with the following parameters, for pooled sexes: P. horkelii L-infinity = 126.93, k = 0.19 and t(0) = -1.51; P. percellens L-infinity = 109.31, k = 0.16 and t(0) = -1.78; Z. brevirostris L-infinity = 60.37, k = 0.24 and t(0) = -1.42. Our results are essential to understanding the resilience and vulnerability of these species to harvest, which can contribute to management and conservation actions of these species. (AU)