Dead fan mussels litter a beach on Lesvos, in the eastern Aegean, in a 2020 file photo.
Living populations of the endangered noble pen shell (Pinna nobilis) are now found in only two locations in Greece: the Gulf of Kalloni on Lesvos and the Amvrakikos Gulf in northwestern Greece. Even in these areas, illegal fishing threatens the species, raising the risk of its complete extinction from Greek waters. A conservation program launched this year by the Natural Environment and Climate Change Agency (NECCA) aims to protect the species, raise public awareness and explore repopulating efforts in other areas.
Known for its large shell, and also known as the fan mussel, Pinna nobilis is endemic to the Mediterranean, with shells growing to over a meter long and a lifespan of up to 45 years.
The species has been under pressure for decades due to overfishing and the use of illegal tools that damage the seabed, leading to its protected status since 1992.
However, a parasitic pathogen, which appeared in the Western Mediterranean in 2016 and reached Greek waters by 2018, has pushed the species to the brink of extinction.
At present, the fan mussel is only found in the Gulf of Kalloni and the Amvrakikos Gulf, having disappeared from the rest of Greece. Earlier this year, NECCA launched a program to monitor these populations, assess their reproductive success, propose conservation measures and raise local awareness. The program is led by Eco-Sustain, with scientists from the University of the Aegean and Aristotle University of Thessaloniki.
Legislation
“Even in these last habitats, the species is under significant pressure,” says Stelios Katsanevakis, professor of oceanography at the University of the Aegean and head of the research team. “In Kalloni, fishermen use a pull-along tool called an ‘argalios’ for harvesting clams, which can damage the seabed. Although regulations require it to be used at least 500 meters from shore, it is often used illegally closer to land. In the Amvrakikos, an illegal tool known as a ‘trataki’ is used to catch shrimp, causing further damage to the seabed. Additionally, the shallow waters make Pinna nobilis vulnerable to swimmers who collect them for food.”
Scientists are working to transplant the noble pen shell from shallow waters to safer locations to create new colonies. “We place larval collectors on the seabed to provide a surface for the pen shells to settle. Our goal is to raise young pen shells in cages until they are ready for transplantation,” Katsanevakis explains.
Awareness campaigns are also being conducted to educate local communities and discourage illegal fishing. “In these small communities, everyone knows who the illegal fishers are. We want to create a negative perception of these practices,” he adds.
New species
As Pinna nobilis declines, another species, Pinna rudis, is beginning to spread in Greek waters. “It’s smaller and was once rare, but now we see it more often around Crete and the Ionian Sea,” Katsanevakis says.