The Mar Menor is a hypersaline coastal lagoon representing one of the most iconic natural areas in Southeastern Spain. However, it has suffered several catastrophic environmental events causing an exceptional eutrophication status. A study was performed to assess the recruitment of oysters in the Mar Menor, determine their taxonomic allocation and evaluate functionality in filtration and growth A total of 45 spat collectors were installed in June 2020 and posteriorly retrieved in October 2020. In total, 3431 oyster recruits were counted. Two species of oyster Ostrea edulis and O. stentina, inhabit the Mar Menor, but they are indistinguishable at the morphological level when they are small. Thus, a genetic tool was developed to identify both species. From a total of 90 oyster recruits, 95% of them corresponded to O. stentina. Finally, growth rate and clearance measurements were conducted on 661 oysters over 6 months under laboratory conditions to explore their possible use in the bioremediation of the lagoon. (c) 2022 Elsevier B.V. All rights reserved.