The Fan Mussel Pinna nobilis on the Brink of Extinction in the Mediterranean

Abstract

The fan mussel (or pen shell), Pinna nobilis, is an emblematic large bivalve, endemic to the Mediterranean Sea. Due to various anthropogenic impacts, its populations had substantially decreased the last century, which led to its strict protection by international and national legislative instruments since the 1990s. Since 2016, P. nobilis has been suffering from mass mortality due to a pathogen infection, which devastated its populations. Currently, the species has become locally extinct in most of its previous range and has therefore been flagged as Critically Endangered by IUCN's Red List in 2019. Surviving populations persist only in a few scattered lagoons or enclosed bays and in the Sea of Marmara, which is still unaffected. Substantial efforts have been made since 2016 by the scientific community for the in situ and ex situ conservation of the species. Although, these have not yet proven fully successful, there has been substantial progress in efforts to breed the species in captivity and to understand the dynamics of the pandemic, as well as in disentangling the role of unaffected populations for potential recovery. The following years seem to be critical for the survival of the species. By further strengthening collective efforts there is still hope that the species can be saved from extinction.