Settlement of Bivalve Spat on Artificial Collectors (Net Bags) in Two Commercial Mussel Parks in the North-Western Adriatic Sea

Among aquaculture activities, shellfish culture is considered more sustainable and beneficial in terms of food security. Currently, only a few bivalve species are reared and there is a need to explore the possibility to introduce new candidates for shellfish farming. Due to the lack of information on bivalve recruitment in the North-Western Adriatic Sea, in this study, the possibility to collect natural spat of commercial species was investigated. Artificial collectors (net bags) were deployed in two sites, Pellestrina and Caleri (North-Western Adriatic Sea), within two commercial mussel parks, during the spring–summer and summer–autumn periods. At both sites, collectors were placed at a distance of 1 m from each other, from 5 to 14 m depth. The influence of season, site and depth on bivalve recruitment was inspected and the presence of invasive species was also evaluated. In all, 28 bivalve taxa were found, and a higher settlement rate was observed in summer–autumn compared to the spring–summer period. <i>Mytilus galloprovincialis</i>, <i>Flexopecten glaber</i>, <i>Mimachlays varia</i> and <i>Aequipecten opercularis</i> were the most abundant species in spring–summer. In the summer–autumn period, in both sites analysed, a very high quantity of <i>Anadara transversa</i> and <i>F. glaber</i> were found. Indeed, these species were dominant at Pellestrina and Caleri, respectively. Another non-indigenous species, <i>Arcuatula senhousia</i>, was also detected. Relevant amounts of Pectinidae spat, <i>F. glaber</i> in particular, were collected and the optimal depth range for the scallop spat collection was found to be between 8 and 14 m. Our results highlight the relevant potential of Pectinidae spat collection along the North-Western Adriatic coasts, even though the presence of invasive species needs to be monitored.