Age and growth of two Sharpnose Shark species in subtropical waters of Southwestern Atlantic

Age and growth of the subtropical populations of the Brazilian and the Caribbean 198 sharpnose sharks (Rhizoprionodon lalandii and R. porosus) were determined combining direct 199 and indirect ageing methods, maximizing the use of available information. The growth 200 parameters Linf (mm) and k (year-1) using vertebrae ageing for R. lalandii were 661.9 and 1.14 201 for males and 751.7 and 0.59 for females, and for R. porosus were 1,035.7 and 0.40 for males 202 and sample were not available for female vertebrae analyses. The parameters of length-203 frequency analyses using ELEFAN for R. lalandii were 762 mm and 0.71 year-1 for males and 204 791 mm and 0.67 year-1 for females; and for R. porosus were 1,040 mm and 0.41 year-1 for 205 males and 1,165 mm and 0.31 year-1 for females. Growth during the first year of life of R. 206 lalandii was 80.3% and of R. porosus was 55% in relation to birth size. Both species presents 207 rapid growth, mainly in the first year of life. The growth estimates are even faster than those 208 reported in previous studies from tropical populationsCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES