Reviving Oyster Aquaculture in Romania: A Scientifically Driven Study Aiming at Obtaining Missing-Link Data for Successful Production

Oyster aquaculture offers promising opportunities for diversifying marine production in the Romanian Black Sea, where favorable environmental conditions and recent regulatory developments support shellfish farming. This study aimed to generate baseline data for the cultivation of the Pacific oyster, Magallana gigas, through an in situ experimental trial conducted off Mamaia Bay, Romania. A 50 m experimental long-line system was deployed at 13.5 m depth, and triploid oysters were cultured for one year at two depth horizons (3 m and 6 m). The growth performance, meat yield, Condition Index, microbiological quality, environmental parameters, and epibiotic communities were monitored monthly. Cultivation depth significantly influenced oyster growth, with individuals reared at 6 m consistently achieving a greater wet weight and shell length than those at 3 m. Growth rates peaked during spring, and meat yield values indicated good commercial quality. Environmental monitoring showed strong seasonal variability, with high summer temperatures and reduced dissolved oxygen associated with increased mortality. Microbiological analyses revealed higher bacterial loads during warm months. The Condition Index classified the oysters as generally “fine” to occasionally “special”. Overall, the results demonstrate that Black Sea conditions can support successful cultivation of M. gigas, although seasonal environmental stress and epibiosis require appropriate farm management.