Integrating local knowledge and ecological approaches to improve aquaculture management and conservation

Aquaculture plays a crucial role in global food security and in the transition toward sustainable, low-impact food systems. In the Mediterranean, mollusc farming, particularly mussels and oysters, represent both a major economic sector and a key element of coastal cultural heritage. However, climatic and biological pressures are increasingly challenging the industry, prompting adaptive strategies such as mollusc transfers between farms and the expansion of oyster farming, considered more tolerant to temperature fluctuations and environmental stress. This PhD project, developed through collaboration between the business sector and the University, aimed to investigate emerging stressors in aquaculture and strengthen connections among stakeholders, scientists, and management institutions. To achieve these goals, an integrated and multidisciplinary approach combined literature analysis, stakeholder knowledge, field surveys, and molecular tools. The study first synthesized current knowledge on fauna associated with Mediterranean mussel and oyster habitats, identifying key pest and non-native species, and knowledge gaps. Mussel assemblages were the most studied and species-rich, with higher diversity in natural habitats, whereas Pacific oyster-associated fauna remained poorly investigated. Within this framework, a survey of mollusc farmers examined how aquaculture practices influence the introduction and spread of non-native and pest species. Farmers provided information on species occurrence, impacts on productivity, and transfers of seed and adults across Italy and beyond, confirming aquaculture as a key vector in the spread of associated fauna. subsequently, field surveys along the Italian Adriatic coast produced the first comprehensive inventory of benthic fauna associated with farmed bivalves, revealing numerous non-native and pest taxa, including frequent oyster infestations by Polydora worms. Morphological and molecular analyses confirmed, for the first time in the Mediterranean, the presence of Polydora websteri and P. caeca, globally recognized oyster pests. Overall, this research advances ecological baselines, identifies major biological risks, and supports adaptive management strategies to enhance sustainability in Mediterranean mollusc aquaculture.