Handling of the Bivalve Pinna nobilis, Endangered and Pathogen-Affected Species, for Controlled Reproduction: Precautions Taken

Following the increased mass mortality of Pinna nobilis populations in the Mediterranean, reliable protocols for the transport, maintenance, and controlled reproduction of this highly endangered species were drawn up within the European Life Pinna project. To test these protocols, the large Pinnidae Atrina fragilis, which shares similar habits to P. nobilis, has been used. In December 2022, a transport trial of nine specimens of A. fragilis from Trieste (NE Italy) to Camogli (NW Italy) was carried out. Two positioning (vertical and horizontal) of the specimens were tested inside the transport box. In the laboratory, after acclimatization, the specimens were placed inside three tanks and fed three times a week with a mix of live microalgae and artificial feed. The transport and maintenance protocols tested on A. fragilis were then applied to 11 P. nobilis collected in the Venice lagoon (NE Italy) and transported to the laboratory in June 2023. Due to the possible infection with Haplosporidium pinnae, considered one of the main etiological agents of mass mortality, P. nobilis individuals were evaluated through molecular analyses during their stay in the tank. Furthermore, these specimens were used as breeders: They spontaneously released already fertilized eggs, as a consequence of transport stress. Rapid larval development stopped at the early veliger stage, and the larvae were fed three times a week with a mixture of microalgae. After the reproduction period, the four specimens that survived 6 months in the laboratory, and constantly tested negative for H. pinnae, were transplanted to the Capo Mortola Marine Protected Area (Liguria, Italy) and monitored monthly.