Dissertação de Mestrado em Engenharia Ciências da Engenharia – Engenharia Zootécnica ; The growth and breeding cycle (sex ratio, size at first spawning, spawning season and recruitment) were studied for three populations of Scrobicularia plana (Da Costa, 1778) along the European Coast: Minho, Portugal; Trondheim, Norway and Terneuzen, Netherlands. The Von Bertalanffy growth equation was used to describe growth in S. plana. Using the collected data on shell length, somatic mass and animals age, the growth constant (K) was computed for the three populations. No clear pattern for growth rate related with latitude was observed: the Portuguese population showed a slower growth rate (K=0.268 and K=0.185 for shell growth and somatic growth, respectively), the Dutch showed the highest growth rate (K=0.368 and K=0.478), following by the Norwegian population (K=0.332 and 0.346). In the other hand, reproduction showed a clear pattern related with latitude, with the Portuguese population showing a longer reproductive season than the other two northern populations. A female to male sex ratio of 1.6:1 was registered for Norway, 3.55:1 for the Netherlands and 1.27:1 for Portugal. The Portuguese S. plana reaches sexual maturity at a bigger shell length (the minimum shell length observed was above 25 mm) than the studied northern populations (20.5 mm for the Netherlands and 17.5 mm for Norway). In fact, the size at which animals reach sexual maturity increases from northern to southern populations in this study. The recruitment in Portugal occurred throughout autumn and winter, with the peak in November. At the other locations, no recruitment was registered so far. In all populations, the gonadal development seemed to occur at the expense of the somatic mass. ; O crescimento e o ciclo de reprodução (razão sexual, tamanho à primeira desova, época de reprodução e recrutamento) foram estudados para três populações de Scrobicularia plana (Da Costa, 1778) ao longo da costa europeia: Minho, Portugal; Trondheim, Noruega e Terneuzen, ...