The skeletochronological analysis of pectoral spiny rays in the silurid Arius proops, collected during the "little summer of March", confirms the presence of a slow growth period during March and April in the rivers of French Guyana. Moreover, this study shows that the longevity of the species is short, 3 and a half years for the females and 3 years for the males, while their growth rate is relatively high, especially during the first half of their life.