Collaborating with mollusc farmers to tackle alien species challenges in aquaculture

Aquaculture is a major vector for the introduction and spread of non-indigenous species (NIS), with negative ecological and economic implications. We used local ecological knowledge (LEK) to study, through questionaries, farmers' awareness of NIS and their observations of ecological changes in oyster and mussel aquaculture in the Adriatic Sea. Farmers indicated translocation practices involving seeds and adult mollusks between Italy, Greece, France, and Spain, both inside and outside the Mediterranean basin, which could facilitate the spread of NIS. Most farmers claimed to know what NIS are and reported observing them in their farms, yet only a few could precisely recognize a limited number of these species. They also noted increases in ascidians, barnacles, and hydrozoans, which they believe harm mollusks and reduce marketability. Our results show that LEK is a valuable tool for identifying issues relevant to NIS management in aquaculture. Training programs should be implemented to enhance farmers’ ability to recognize alien species and contribute to their early detection. Furthermore, cross-border collaboration and partnerships between scientists, policymakers, and farmers are essential to managing the transport of alien species through aquaculture in the Mediterranean.