The fan mussel Pinna nobilis is threatened by several anthropogenic disturbances that are only partially mitigated by current conservation measures. In the Faro Lake Natural Reserve, the fan mussel population suffers from insufficient recruitment while, due to periodic dredging, a high larval supply within the canals does not support a stable population. In the present study, a robust number of fan mussel specimens were transplanted from a high-impact site to a guarded area to test the effects of transplantation on future conservation efforts. Over a 12-mo period, high survival and elevated growth were observed in the test population in comparison with the local population, demonstrating transplantation as a feasible and efficient method to prevent P. nobilis population decline. Such small-scale experiments provide useful indications for better management approaches for both of the threatened species and the natural hosting environment.

The introduction rate of alien species in the Mediterranean Sea is rapidly growing, and their taxonomical identification is increasingly challenging. This uncertain identification often leads to an incorrect estimation of the number of alien species, their route of introduction, and their potential negative effects. This is particularly true for some bivalves, which are characterized by high variation in their shells, resulting in uncertain morphological identification. This is the case for two alien bivalves, i.e., an Isognomonidae and a Malleidae species, both characterized by confused historical colonization records in the Mediterranean Sea, misidentifications, and controversial and changing nomenclatures that have insofar negatively affected our knowledge on their geographical distributions. In this respect, molecular approaches provide a strategy that is especially useful when traditional taxonomy fails, and DNA barcoding is a powerful and well-known tool to obtain reliable identifications through efficient molecular markers. In this work, we used the 16S rRNA marker to assess the preliminary identification of Isognomon sp. and Malleus sp. specimens from different localities in the Southern Mediterranean Sea. Bayesian inference (BI) and maximum likelihood (ML) methods were applied to test the monophyly of the phylogenetic linages and to clarify their taxonomic positions, allowing a complete overview of the colonization and spreading of these two alien bivalves in the Mediterranean Sea. In particular, the Isognomon sp. specimens were identified as the Atlantic I. bicolor, highlighting that previously suggested invasive migration patterns, (i.e., the Lessepsian migration), must be reconsidered with stronger critical attention in light of currently occurring global changes.