For decades the rayed pearl oyster (Pinctada imbricata radiata) has quietly thrived beneath the Mediterranean waves. Yet, despite its abundance, this oyster remained absent from markets in Greece—not due to a lack of quality, but because Greek law didn’t officially recognise it as a commercial species.
Thanks to an initiative led by the University of Patras and supported by the European Maritime and Fisheries Fund (EMFF), the tide is turning. The team closed the legislative gap for the harvesting of this oyster. It is now being developed into new seafood products, offering additional income for local fishers as native shellfish stocks decrease.
The Mediterranean’s overlooked guest
Native to the Indo-Pacific region, the rayed pearl oyster is firmly embedded in Mediterranean ecosystems. Despite being a non-native species, the rayed oyster is abundant and thriving. Meanwhile, the native shellfish—striped quinces, brown venus clams, European flat oysters— are struggling due to combined pressures of climate change and overfishing.
However, as the rayed oyster lives in a legal grey, unregulated zone, mislabelling and illicit sales are common, and its potential remains largely ignored.
Legal harvests, local prosperity
Determined to change that, a multidisciplinary team from the University of Patras came together with a mission: to give the rayed pearl oyster its place into Greek commercial fisheries.
Supported by EMFF funding, the team included biologists, food technologists, economists and regulatory experts. They mapped wild stocks, identified safe harvesting zones, and analysed yields and nutritional profiles to ensure quality and safety. Market researchers spoke to restaurateurs, retailers and consumers and found an appetite for this responsibly sourced delicacy with a distinctive Mediterranean identity. Processing specialists then ran trials that showed smoking and salting the oysters could boost fishers’ revenues without large capital costs. Draft regulations on minimum size, open seasons, and traceability were submitted to Greek authorities—backed by rigorous, peer-reviewed evidence.
“Legalising the rayed pearl oyster turns a non-native arrival into a catalyst for coastal prosperity. Science and smart regulation let us convert what was once illicit by-catch into a flagship of sustainable Mediterranean seafood,” explains Dr Theodorou, Associate Professor at the Department of Fisheries & Aquaculture of the University of Patras.
With the legal groundwork in place, the Greek government issued the first pilot quota for rayed pearl oyster fishing. Smoked oysters soon appeared in local restaurants, bringing new income to fishers.
Prosperity for fishers & delicacy for foodies
The story of the rayed pearl oyster is just beginning. The next steps include refining processing lines, scaling up land-based infrastructure, embedding the harvest code into law, and exploring export markets to maximise value. The partnership between scientists, public officials, and the fishing community has created a model for managing non-indigenous species sustainably—one that could be replicated across the Mediterranean.
More information
Web page of the project: Pearl Oyster Sea Food
Episode of Euronews on invasive species: Mediterranean Indigenous Species – Pearl Oyster (Pinctada imbricata radiata)