Growth of mussels Perna perna and P. viridis growing in suspension in horizontal arrangement in stakes in Lagoon of Chacopata Araya Peninsula, Venezuela was evaluated simultaneously, during 8 months. Spats were collected at locations adjacent to the lagoon. The cultivation element was a plastic mesh of 50 cm × 8 cm wide, with which were formed a total of 24 replicates for each species, being sown manually and placed in suspension on wooden stakes. Each species of mussel was evaluated every month in shell length and muscle, gonadal lobes, other somatic tissues dry biomass and survival, while weekly records were taken from different environmental parameters. Both species showed a survival > 90% throughout the experiment. The growth patterns of both species were similar, with some variations. P. viridis showed higher growth rate in shell length, reaching at the end of the study 82.1±0.92 mm and P. perna 76.7±2.61 mm, but P. perna showed improved performance relative tissue mass-length. At study end, the gonad of P. perna reached more than 100% with respect to P. viridis. In both species during the last month of study, the masses of all tissues decreased significantly suggesting a stress event associated with high temperatures and decreased phytoplankton biomass. The lagoon of Chacopata system is presented as an excellent environment to start the production of both mussels, which could be an economical alternative for coastal communities in the area.