The Mediterranean endemic bivalve Pinna nobilis is critically endangered because of a mass mortality event that is impacting its populations throughout the Mediterranean Sea. However, coastal lagoons seem to offer a degree of “resistance” against the parasite.

Pinna nobilis first appeared in the Mar Menor lagoon (Spain) and rapidly became an important component of the benthos. However, colonization of the lagoon was cut short in 2016, when a massive mortality event occurred, possibly as a consequence of the environmental collapse that occurred in the lagoon (and not related to the disease that was affecting the rest of Mediterranean sites).

This study characterized the P. nobilis population in the Mar Menor lagoon before the environmental collapse of 2016; identified the main routes into the lagoon and analyzed the colonization process before 2016; and conducted a first assessment of the situation of P. nobilis in the lagoon following the eutrophication crisis.

The authors stress that the lagoon is one of the few remaining sites where fan mussels still survive the disease, so maintaining good environmental conditions and healthy fan mussel populations should be a priority.

Giménez-Casalduero et al. (2020) Pinna nobilis in the Mar Menor coastal lagoon: a story of colonization and uncertainty. Marine Ecology Progress Series 652:77-94.