Age and growth of Pimelodella pappenheimi (siluriformes, pimelodidae) from an Atlantic Forest Stream in Southern Brazil

Abstract

Studies were performed to determine the growth curves in length and weight for Pimelodella pappenheimi in the "das Pombas" stream, a coastal stream susceptible to the flash flood phenomenon. Samples were collected from September-95 to February-97, monthly, using electric fishing. The fishes were measured in total length and weight. A total of 156 pairs of otholits were taken for ring reading. The Ford-Walford transformation allowed the use of von Bertallanffy expression. The pale ring formation was annual, and it occurred between the summer and the autumn. This species grews in length according to Lt=15.86 (1-e-0.57(t+0.1551) ) equation and in weight according to Wt= 24.23 (1-e-0.57(t+0.1551) )3.12. The increase in length was faster until the second year of life, whereas the increase in weight was more noticeable between the first and fourth years of life.