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The noble pen shell (Pinna nobilis) is an endemic species with rich history and of particular significance for the marine ecosystem. It is the largest bivalve in the Mediterranean and cannot be found anywhere else than in this unique, enclosed sea. Noble pen shell individuals can grow more than a metre in length, weigh more than three kilograms, and live as long as 50 years. They live in shallow areas under the influence of tides, which can leave the noble pen shells partly outside of the water. The noble pen shell is present even at depths of 60 metres, but it is most numerous on seagrass meadows, where it uses its byssus threads to attach itself to the substrate and become a part of one of the most productive marine habitats.

The noble pen shell offers a hiding place, feeding ground and nursery for a large number of organisms that we know by a single name: epibionts. Colonising the solid structure of this bivalve has proven to be a successful strategy for the survival of both immobile and mobile organisms. An individual noble pen shell can harbour more than 35 species of animals and algae.

Autumn 2016 marked the beginning of one of the hardest and most disastrous periods in the history of the noble pen shell’s existence. A newly discovered parasite, Haplosporidium pinnae, in synergy with the bacterium Mycobacterium sherrisii, killed noble pen shell populations in the Spanish Balearic. By 2020, these pathogens dispersed uncontrollably throughout the Mediterranean and infected almost all individuals in the wild. While thousands of individuals still thrive in the lagoons of France,
Spain, and Italy, only ten individuals per country can be found in the
open waters of the Mediterranean.

Find out more about the epidemic and pathogens by clicking on the link.

The first young noble pen shell named “Omišanka” arrived at the aquarium on 19 November. Jelena Kurtović Mrčetić, a biologist from the Public Institution “More i Krš”, found a young noble pen shell, 1.5 cm in length, in the Omiš harbour at a depth of 6 metres after a thorough collector inspection. A few days later, “Rovinjke” arrived, individuals found after a collector inspection in the bay of Leso, headed by Andrej Jaklin, PhD. At the end of December, “Brionke” also arrived at Aquarium Pula. They were found during a careful inspection of larvae collectors in Brijuni National Park and delivered by the team headed by Tatjana Bakran-Petricioli, PhD. Young individuals are fed multiple times a day: by hand (at least four times) and with the help of an automatic feeder (every hour).

Public education about problems affecting marine ecosystems has always been a vital part of the conservation of nature and its resources. With that in mind, Aquarium Pula accomplished a series of achievements in raising public awareness about possible noble pen shell extinction. The main goal was to present our activities to the public, sensitise people and give them an incentive to become involved in the conservation of this noble species. Numerous reports from the field provided by citizens are often crucial to getting the bigger picture about the status of the population in need of our protection.

A short documentary, “Noble Sanctuary”, shows the noble pen shell as the biggest Mediterranean bivalve whose absence would adversely affect the balance of the marine ecosystem that we know today. It introduces the audience to the mass mortality event; the unexpected pathogen spread that brought the noble pen shell to the brink of extinction. Watch “Noble Sanctuary” and follow the activities of the scientific community and Aquarium Pula staff that dedicate their time and resources to conserving this noble species vital for the marine ecosystem.