Ocean literacy and scientific data acquisition through citizen science campaigns: a mixed approach in the Maltese Islands to collect information on Pinna nobilis and Pinna rudis

The genus Pinna includes two species in the Mediterranean Sea: Pinna nobilis and Pinna rudis. Both these species are under threat from multiple stressors. Pinna nobilis, in particular, has been exhibiting mass mortality events (MMEs) since 2016. The population and distribution of these species have never been comprehensively explored in the Maltese archipelago, and in this work, we collate information collected between 2006 and 2019 through a number of SCUBA underwater visual census monitoring programs. The logistical barriers surrounding SCUBA-based sampling techniques and the low-density distribution of these species constitute significant obstacles to an extensive conventional population assessment. Citizen science was thus also deployed in this study to supplement the data collected through SCUBA surveys: recreational SCUBA divers worked as citizen scientists, providing data on the distribution of these two endangered species from areas never explored before. This information can be used for assessing the conservation status of P. nobilis and P. rudis in Maltese waters, whilst contributing to the next generation of ocean-literate citizens.