Wild Pacific oyster Magallana gigas (Thunberg, 1793) populations in Romanian Black Sea waters – friend or foe?

A relatively small population of Magallana gigas was discovered near the Agigea harbor (Constanța, Romania) in 2017. The DNA barcoding method was used to confirm the morphological identification of the species. We consider this colony to be the first instance of a possibly stable Pacific oyster population in the Black Sea, outside of farming activities. The possible impact on native ecosystems is briefly discussed.