Age and growth of Pacific cownose ray, Rhinoptera steindachneri: a species with intermediate growth and shorter lifespan than expected

Context. Rhinoptera steindachneri is the third-most abundant batoid species in the artisanal gillnet fishery of the Gulf of California, but there are limited age and growth data available for management. Aims. The aim was to estimate age and growth of this species from vertebral centra of 276 individuals. Methods. Two adjusted data sets were constructed on the basis of the birth and capture months and defining adequately the birth band. Individual growth was described through a multi-model approach and inference by using von Bertalanffy, Gompertz, and Logistic models (two and three parameters), and a two-phase growth model (four and five parameters). Key results. The model with the best fit to the size-at-age data was the two-phase model for both sexes (females: Dw(infinity )= 91.21 cm; k = 0.25 year(-1), Dw(infinity) = 46.2 cm; males: Dw(infinity) = 79.1 cm; k = 0.42 year(-1), Dw(infinity) = 45.5 cm). Maximum ages ranged from 9.92 to 10.75 years (female) and from 6.92 to 7.67 years (males). Maturity age was estimated in 3.92 years (females) and 3.72 years (males). Conclusions. Rhinoptera steindachneri is a batoid species with intermediate growth and a shorter lifespan than for confamilial species and even than species with similar reproductive traits. Implications. The need to carry out age validation studies for this species is highlighted.