The 1.2m giant clam thought to be extinct 'reappears' off the coast of Croatia

A parasite almost wiped out the giant Pinna nobilis mussel in 2016. However, recently, Croatia discovered that this mussel is growing again and is making efforts to preserve it.

Marine biologists say a species of giant clam that was thought to be extinct recently reappeared in the waters off the coast of Croatia with a sudden increase in numbers.

Giant clams in the Mediterranean Sea. (Photo: Alamy Stock)

This 1.2 meter long clam, called Pinna nobilis , also known as the 'noble pen clam' or 'fan clam,' began to decline rapidly in numbers due to infection with a parasite that spread in Mediterranean Sea in 2016.

This parasite causes mussels to die of starvation quickly. This pathogen nearly wiped out the Pinna nobilis mussel population off the coast of Spain, then spread to other coastal areas.

Croatian scientists say the number of Pinna nobilis mussels has decreased sharply across the region, with only about 10 individuals in the Croatian Adriatic Sea alone until recently.

However, last year, a diver discovered about 20 Pinna nobilis clams near the northern coast of the Istria Peninsula.

Expert Sandro Dujmovic of the Natura Histrica Organization, which manages Istria's protected areas, said scientists were quite surprised by this information.

According to him, it is unclear why the Pinna nobilis mussels reappeared, but 'this is a sign that they are still reproducing themselves'.

Since the beginning of the year, biologists have collected about 100 Pinna nobilis clams and brought them to the aquarium in the Adriatic city of Pula.

Here, they are raised in a clean water environment, eliminating parasites, increasing their resistance and ability to survive, then returning them to the wild.

Experts say the Croatian Government has decided to increase funding for research on conservation of this species.

The Pinna nobilis mussel, which can live up to 45-50 years, is up to 1.2 meters long when mature. This species is found only in the Mediterranean Sea, standing upright like boats, their pointed ends anchored in sandy seagrass meadows with threads that shine like gold.

With its wing-shaped shell padded with metallic mother-of-pearl and its production of rare, pure marine silk fibers, Pinna nobilis is one of the most iconic symbols of the Mediterranean region.

The Pinna nobilis mussel plays an important role in the marine ecosystem. (Photo: Skaphandrus).

In ancient times, the silk fibers secreted by the Pinna nobilis mussel were exploited by the Phoenicians of the Mediterranean region to weave luxurious clothes. Artisans also use the mother-of-pearl shell of the Pinna nobilis clam to carve expensive buttons.

Some people believe that the rare silk harvested from the sea could be the basis for the legend of the golden fleece sought by Jason in Greek mythology.

Pinna nobilis clams are also considered an indicator of ocean health , as their shells record chemical and physical changes in the surrounding waters.

They play an important role in the marine ecosystem due to their ability to purify ocean water, providing a fresh habitat for other creatures.

However, this world's second largest giant mollusk is on the brink of extinction and is listed as a species that must be urgently protected.