“With the contribution of the LIFE programme, the European Union’s financial instrument supporting environmental, nature conservation and climate action projects.”
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What is LIFE PINNARCA
LIFE PINNARCA is a European project devoted to the protection and restoration of the fan mussel Pinna nobilis populations in the Mediterranean Sea.
It is has been conducted with the contribution of the LIFE programme, the European Union’s financial instrument supporting environmental, nature conservation and climate action projects.
The main objective of LIFE PINNARCA is preventing the extinction of Pinna nobilis at the short-medium term, through public awareness and collaboration, gathering existing information on the remaining populations and developing active recovery actions.
Pinna nobilis background
The fan mussel Pinna nobilis (Linnaeus, 1758), an endemic and protected bivalve of the Mediterranean Sea, is affected by a Mass Mortality Event (MME) provoked by the parasitic protozoan Haplosporidium pinnae started in 2016 in Spanish waters. The populations of Pinna nobilis in the open sea have almost completely disappeared from the Mediterranean coasts, with a mortality rate close to 100%. Countries such as France, Italy, Greece, Cyprus, Montenegro and Croatia have already reported the impact of the MME. The spread of the disease is so fast and its consequences so hard that the extinction of the species has been considered plausible. A compilation of recommended actions has been recently suggested (IUCN, 2019).
Remnant populations denoted as open circles. From Katsanevakis et al 2021
From the legal side, the fan mussel has been labeled as 'En Peligro de Extinción' by the Spanish 'Catálogo Nacional de Especies Amenazadas (Orden TEC/596/2019)'. Given the fast spread of the disease, and the extreme mortality rates observed, the IUCN has recently included P. nobilis in its red list of species endangered with extinction worldwide.
The disease of the fan mussel is caused by a recently discovered parasitic protozoan, Haplosporidium pinnae, to our knowledge affecting only P. nobilis. Other bacterial pathogens have also been observed in weak fan mussels, probably acting as opportunistic agents, such as Mycobacterium sp or infecting fan mussels reared in captivity, such as Vibrio shiloi. Altogether, these opportunistic agents form a conserved consortium of microorganisms cooperating to induce pathogenesis.
H. pinnae produces a systemic infection of the connective tissues, where free uninucleated stages (1.8- 4.6 μm maximum length) and plasmodia can be observed, while spore formation takes place in the digestive tubules epithelium, thus disrupting the digestive function and, finally, causing the death of the individual. . In the case of H. pinnae, although the possibility of an intermediate host cannot be discarded, healthy individuals confined with sick individuals appear to get infected directly, which supports direct transmission. The combined effect of sporulation on the digestive gland with direct transmission that this parasite seems to possess would explain its unprecedented lethality.
Concerning survival of P. nobilis at the wild, after different waves of the MME, a search for survivors from 2018 in Spanish coasts has produced a very discouraging result: only few isolated alive individuals have been found (2 in Columbretes Islands, 6 in Balearic Islands and 3 in Cap de Creus). It is noteworthy that two small Spanish fan mussel populations remain not severely impacted by the MME, but they are both located in paralic environments (Delta del Ebro and Mar Menor lagoon). The reason why these populations remain at least partially protected has been associated with particular salinity conditions, either lower or higher, respectively than the open sea. In the Alfacs Bay, there are evidences that salinity conditions below 36 confer certain tolerance against the parasite, whereas ranges below 30-32 in the Fangar Bay, appear to prevent the infection.
Concerning the second population (Mar Menor lagoon), the remaining fan mussels that had survived the environmental collapse in 2016, before the arrival of the disease, suffered a severe flood episode in September 2019. The total of specimens that remain alive is unknown, but at least several docens have been located in the least affected areas.
The mass mortality of fan mussels along the French coasts first appeared in the western coast of Corsica in autumn 2017. Populations of P. nobilis remain alive in coastal lagoons both in Occitania (Leucate, Thau, Fos: Rhône’s delta) and in the east coast of Corsica (Diana). In Diana a dense healthy population was observed in June 2019. In Thau lagoon, well-known populations have been monitored for several years.
In the Italian coast, the first description of MMEs in 2017 was reported in the Tyrrhenian Sea, in the region of Campania, in the islands of Ischia and Procida, and in the Sicilian coasts of Messina. By March 2018, the populations of Sorrento and from the islands totally disappeared. Few young individuals were observed in the south of the coast (Cilento) in 2019 and in the internal marine lakes of Phlegrean area (north of Naples). Mortality was also reported in many other Italian regions, like Sardinia and Tuscany. In Sardinia, in Oristano and in Asinara Island (north-west of Sardinia) mortality was reported since 2018, and currently no live individuals are present in these areas.
In the western Ionian Sea (, the first evidence of mortality of P. nobilis (40% of the individuals) was reported in summer 2017. Later, in the early summer 2018, the western Ionian Sea P. nobilis populations suffered very high mortalities, with up to 100% mortality in 3 months.
The status of P. nobilis in the eastern Ionian Sea was assessed, based on data collected at 69 sites in 2019. Mortality rates exceeded 80% by August 2019, and kept increasing at that time. In autumn 2019, in all sites surveyed there was almost no live individual. The only locality, where mortality rates were low (40%) was the National Marine Park of Zakynthos, surveyed in August 2019. However, in 2020 the fan mussel population in NMPZ was largely affected, with only few live individuals left, mostly juveniles. Nevertheless, the eastern Ionian Sea remains under-sampled.
In a broader context, the mortality has reached practically all the Mediterranean basin in the open sea, and some sanctuary areas host P. nobilis population in particular conditions. Survivors/resistant individuals are few and far between but the monitoring and protection of those individuals is extremely important for the conservation of the species.
Protection and restoration of Pinna nobilis populations as a response to the catastrophic pandemic started in 2016
Start date: 1 October 2021
End date: 31 December 2024
Acronym and reference
Total budget for the project: 2.249.332€
European financial contribution: 1.347.894€
Illegal collection of mussels
Increasing awareness to a global scale, in order to reduce the possibility of vandalism and illegal collection of the remaining fan mussels, but also to call for broad public collaboration.
Gathering all existing information on the remaining populations and resistant individuals and include it into a data-base integrated within the LIFE Pinnarca webpage. This will provide a more informed background to other countries planning mitigation and recovery actions, so their effectiveness can be fostered.
Increase the probabilities
Developing active recovery actions focused both on the resistant individuals and on the remaining non-resistant populations, in order to increase the probabilities of recovery of the species.
A1) Planning correction measures
A2) Location of optimum sites
C1) Installation of larvae collectors
C2) Exhaustive shallow census
C3) Deep area census
C4) Translocation of individuals
C5) Comparative genomics
C6) Actions for environmental improvement in sanctuary areas
C7) Tank maintenance of healthy individuals
C8) Treatment assays and analysis
Monitoring project actions
D1) Follow up of juvenile individuals
D2) Follow up of resistant individuals
D3) Follow up of Mar Menor sanctuary population
D4) Monitoring and evaluation of project actions
D5) Development of socioeconomic impact study
Public awareness and dissemination of results
F1) General project management
F2) Supervision of project development
F3) After LIFE plan