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Abstract: The reproductive cycle, as well as its nutrient storage and utilization, of two populations of Ruditapes decussatus from the main production areas of this species: Ria de Aveiro and Ria Formosa Lagoon (Portugal) were studied here over a 24month period (May 2010–April 2012). The reproductive cycle of both populations of R. decussatus followed an annual cyclicality that comprised a ripe stage in spring followed by a spawning period that began in late spring and extended throughout summer until early autumn. This extended and continuous spawning period may be an advantageous strategy for this species by ensuring a continuous supply of gametes. Moreover, R. decussatus can adopt different reproductive strategies depending on the geographical origin. The results of both cycle of nutrients stored and nutrients utilization showed that clams of both populations present a high reproductive effort that almost depletes its energy reserves. Nevertheless, while Ria de Aveiro population retrieves them immediately after spawning, the same is not verified in clams from Ria Formosa Lagoon with their consequent debilitation. Also, based on the glycogen pattern it was possible to infer that the Ria Aveiro population is an opportunistic one, while the Ria Formosa Lagoon population exhibited an intermediate strategy. However, both populations could be considered as viable broodstock for intensive hatchery production of juveniles and the observed extended spawning periods presents interesting implications for the implementation of profitable aquaculture. Moreover, this species presented a great capacity for gonadal regeneration, which coupled with its high gonadal development rate would provide larvae during most of the year without extensive and expensive broodstock conditioning. [Copyright &y& Elsevier]