Populations of the endemic Mediterranean fan mussel (Pinna nobilis) have been devastated by a die-off associated with the protozoan Haplosporidium pinnae and mycobacterial and other bacteria disease. The first reports of the die-off occurred in September 2016 in southeast Spain, and it has since spread throughout all Spanish Mediterranean coastal areas, reaching France, Italy, Greece, Cyprus, Croatia, Montenegro and other Mediterranean countries in a few years. To date, only fan mussel populations from the north Adriatic Sea are known to be free of the disease. Data indicates that the protozoan is specific to fan mussel, leaving other invertebrates unaffected (including the congeneric species Pinna rudis). Fan mussel mortality reaches almost 100% in affected populations. When in early 2017, the Haplosporidian protozoan was identified as the probable cause of die-off, the Spanish expert group monitoring the event indicated a high risk that the disease would be spread by marine currents. This, together with the characteristic biology of fan mussels (a K strategist), could eventually cause the ecological, if not total, extinction of the species, representing an unprecedented process in the Mediterranean Sea. As a consequence, in Spain the status of Pinna nobilis was downgraded from "endangered" to "in danger of extinction", while the IUCN recently assessed the species as ‘Critically Endangered’ in its Red List. A rescue programme to maintain individuals in captivity started in November 2017, enabling the study and quick identification of the Haplosporidian parasite. Observations of fan mussels rescued from infected populations led to the hypothesis that some individuals may have some resistance to the parasite, though the disease makes them extremely vulnerable to predators. Other pressures on the mussels include harvesting for its decorative value or as food, destruction of its habitat (Posidonia oceanica and other seagrass meadows), pollution, and indiscriminate boat anchoring.
The overall goal of LIFE PINNARCA is to prevent the extinction of the Mediterranean fan mussel (Pinna nobilis) in the short-to-medium term. The project will carry out urgent measures within the framework of an international collaborative consortium of experts to enable the application of coherent trans-boundary measures.
To project team will focus on three main objectives:
1) Increasing awareness on a global scale, to reduce the possibility of vandalism and illegal collection of the remaining fan mussels, but also to call for broad public collaboration. Actions will be oriented at schools and the general public, including the production of a video, international workshops and volunteering actions;
2) Gathering all existing information on the remaining populations and resistant individuals into a database integrated within the project’s website, to provide information to other countries planning mitigation and recovery actions. This objective will be achieved by implementing a comprehensive census of areas where resistant individuals or unaffected populations are found, as well as installing larvae collectors to assist successful recruitment;
3) Developing active recovery actions, focused both on resistant individuals and the remaining non-resistant populations, to increase the probabilities of recovery of the species. This objective involves efforts to aggregate resistant individuals, translocate vulnerable individuals to safer areas, exchange genetic information among remaining populations, identify locations with optimal conditions to repopulate with healthy fan mussels, maintain individuals in indoor facilities, and develop active measures to improve the environments where healthy non-resistant individuals are still found.
The project is in line with the EU Habitats Directive, 7th EU Environment Action Programme (EAP), Biodiversity Strategy to 2030, EU Action Plans for the species, and the Regional Catalogue of Threatened Species.
- An increase to thousands of individuals in the Mar Menor reservoir;
- The rescue of the still remaining juvenile individuals (3 000 estimated in 2018) in Delta Ebro;
- An increase in the longevity of resistant individuals in open waters and the surviving populations living in reservoirs;
- The beneficiaries expect to find an important number of open water survivors – at least 10 to 15 new potential resistant individuals in each of the partner countries. These individuals will be put together in optimum open water locations, to facilitate their crossbreeding and their protection from predation;
- Reduction of anthropogenic impacts in the reservoirs;
- Raise awareness and knowledge about the species, to avoid poaching and to involve the general public in future protection surveys with volunteers, and to inform fishermen in priority areas;
- Maintenance of individuals in indoor facilities, to study the relationship between the abiotic environmental variables and survival rates, as well as better understand the limits of environmental tolerance of the parasite. This information will help predict the best areas for repopulation with non-resistant individuals;
- Increased knowledge about genetic variability in different environments, comparing non-resistant fan mussels living in open seas to those few that are resistant and have survived the disease;
- Increased genetic diversity of survivor populations by translocating some individuals; Creation of a catalogue of surviving populations, made available in a public database hosted on the LIFE PINNARCA website.