I swim and I stare as my shadow causes panic on the seabed below. Shells snap shut, one, two, three. Alive, alive, alive.
I am so happy to see them: noble pen shells, all improbably but indisputably alive. These giant Mediterranean clams are a species on the verge of extinction, with so few left that it is rare to find one living anywhere in Europe . Often known as fan mussels, the moniker is a suitable one for this beautiful bivalve, its pearlescent point dug into the sand, fanning up to a rounded posterior.
I’m in the Amvrakikos Gulf on the west coast of Greece, where I have the privilege of watching these creatures grow. Their presence is such good news that Spanish scientists have flown in to see the clams for themselves as part of an EU project focused on trying to rescue , and hopefully expand, what is left of the pen shell population. Given the chance, noble pen shells ( Pinna nobilis) can live for 20 years and grow to more than a metre tall.
Only the giant clam is bigger. They are endemic to the Mediterranean, increasing water clarity and biodiversity, and their large shells provide habitat for myriad species. As fans of the pen shell know (and I am the biggest fangirl of all), if you approach carefully you might glimpse its habitual guest – a symbiotic shrimp – inside.
Tragically, after a series of mass mortality events that started in Spain , it is more common to find noble pen shells dead than alive. Humans have exploited these bivalves for centuries, eating .