The aim of this work was to study the dynamics of Alitta succinea population growth in a tropical estuary. The organisms were collected in the polyhaline area of Pina Basin, north-eastern Brazil, in lower and shallow subtidal consolidated substrates, from October 2009 to March 2011. Fifteen samples with a size of 0.01 m2 were collected every month. A total of 2064 A. succinea individuals were measured for growth analysis, and the measure used was the length from prostomium to the 25th setiger. Growth parameters were estimated by the frequency–length distribution data from three different functions (i.e. von Bertalanffy, Gompertz and Richards). The differences in the densities of A. succinea were significant between the months of the dry and the rainy season, with the rain pattern being the factor that most affects the A. succinea life cycle. According to Akaike information criteria, the von Bertalanffy and Gompertz models were the ones that presented the best fit with the growth curve of A. succinea for the studied period. Using the Bhattacharya method for the analysis of modal progression, we identified eight cohorts. The lowest recruitment values were found in July and August 2010, respectively, and the remaining months had numbers of recruits that were representative of the total population. The growth performance index (Ø′) found was 2.86. The maximum longevity indicates that specimens of A. succinea live between 586 and 953 d, and the instantaneous mortality rate (Z) is 1.53 yr−1.