Pinna nobilis is the largest Mediterranean bivalve and a long-lived species, with a life span that can exceed 45 years. Since 2016 a mass mortality event (MME) is causing the death of many P. nobilis populations throughout the Mediterranean Sea.

This study compared the growth of P. nobilis in 12 populations living in different environments in France and Spain. Altogether, 209 shells were processed and used to obtain growth records from the posterior adductor muscle scar.

The results show considerable variability in growth parameters and age among these populations. Multivariate analysis groups the populations in three groups depending on exposure (Sheltered Open-sea, Exposed Open-sea and Lagoons), and a general model is proposed for each group. The authors state that the model can be used as an approximation to calculate the ages of individuals living in similar environments.

The authors highlight that after the MME the only two fan mussels’ populations remaining in Spain, which live in an estuary and a coastal lagoon, occupy habitats that are optimal for fast growth, but individuals show low longevity, thus complicating the long-term conservation of the species.

García-March et al. (2019) Age and growth of the endangered fan mussel Pinna nobilis in the western Mediterranean Sea. Marine Environmental Research