Fan Mussel (Pinna nobilis)

Gozo’s pristine waters offer a glimpse into the life of the Noble Pen Shell (Pinna nobilis), a fascinating and endangered species of Mediterranean clam. Dive into the details of this remarkable bivalve mollusc and learn where to encounter it around Gozo’s dive sites

How to Identify a Noble Pen Shell

The Noble Pen Shell, also known as the Fan Mussel or Nakkra in Maltese, is a large species of Mediterranean clam. Typically, its bivalve shell ranges from 30 to 50 cm in length but can grow up to 120 cm. The shell is elongated, fan-shaped, and relatively fragile, with a glossy inner lining of mother-of-pearl. This clam is anchored to the seabed by strong byssus threads, which are silk-like and can be up to 6 cm long.

Where are Noble Pen Shells Found?

Pinna nobilis is endemic to the Mediterranean Sea and can be found at depths ranging from 0.5 to 60 meters. It prefers soft-sediment areas, such as fine sand or mud, often in anoxic conditions. This species is commonly found in seagrass meadows, especially those of Posidonia oceanica, which provide both food and protection.

Interesting Facts about Noble Pen Shells

Historical Significance: The byssus threads of the Noble Pen Shell were historically used to create sea silk, a luxurious and rare fabric.
Symbiotic Relationships: Pinna nobilis often hosts symbiotic shrimp within its shell. These shrimp are believed to warn the mussel of potential threats, aiding in its defense.
Conservation Status: The Noble Pen Shell is listed as an endangered species due to threats from fishing, habitat destruction, and pollution. Recent years have seen mass mortality events linked to a newly identified parasite.
Research Efforts: Conservation groups, such as the Physical Oceanography Research Group at the University of Malta, are conducting surveys to better understand and protect this species. You can contribute by participating in their online questionnaire at Questionnaire Pinna Nobilis .

Where Can I See Noble Pen Shells?

To see the Noble Pen Shell in its natural habitat, explore the dive sites around Gozo. One notable location is Ras il-Ħobż on Gozo’s south coast, where these impressive bivalves have been spotted at depths of 32 meters. Other dive sites with similar conditions may also provide opportunities to encounter this fascinating species.

Experience the underwater wonders of Gozo and contribute to the conservation efforts to protect the Noble Pen Shell, ensuring this emblematic species continues to thrive in the Mediterranean Sea.