Authors: Nebot-Colomer, Elisabet; Deudero, Salud;Mourre, Baptiste;Fraile-Nuez, Eugenio;Álvarez, Elvira;Albentosa, Marina ;Ruiz, Juan Manuel;Vázquez-Luis, Maite;

The endemic species Pinna nobilis is the most endangered Mediterranean bivalve, facing nearly extinction all over the Mediterranean Sea, hosting its last reservoirs in highly impacted coastal lagoons. Thus, knowledge about the populations' conservation status in these ecosystems is essential. In 2019, the Mar Menor lagoon’s population was considered as a highly vulnerable population (Nebot-Colomer et al., 2021) due to several ecological disasters. The present study represents a continuation of the previous work, which aims to evaluate the resilience of the population, by assessing its reproductive capacity and maintenance of population. To do so, between 2019 to 2022, we installed between 23-45 larvae collectors, monitored 7 permanent individual plots, and conducted visual searches and censuses. None of the methodologies carried out detected the incorporation of recruits in the population. Moreover, a decrease in densities was observed, results agreeing with an increase in the number of dead individuals in the permanent plots. Our results pointed out to opposite signs of recovery of the species, increasing its vulnerability to future disturbances. Therefore, urgent management and conservation actions focused on restoring the ecosystem and protecting P. nobilis individuals are needed to avoid this population extinction.