The Uncertain Fate of Sea Silk – Part 1

Noble pen shell

Arguably one of the most mesmerizing examples of submerged heritage in the Mediterranean Sea is the strikingly beautiful, exceptionally fine and incredibly rare sea silk. Sea silk is finer than the more ‘commonly’ known silk that is produced by the silkworm, as well as being stronger, warmer and lighter in weight. Additionally it is very compact allowing it to be compressed into very small volumes. It will come as a surprise to many that the raw material for sea silk can be found along many parts of the Greek coastline (including that of Attica), often at shallow depths. Many who have snorkeled in the Greek seas will have unknowingly already seen its source. It is therefore somewhat of a paradox why so few people know about sea silk.

Sea silk is made from the long silky filaments, also known as byssus, secreted by a gland at the base of pen shells, especially the noble pen shell (Pinna nobilis). Byssus finds its origin in the ancient Greek word ‘βύσσος’ (byssos) meaning ‘fine thread’. The noble pen shell has an elongated triangular shape and has been known to reach lengths of 130 centimeters. Utilizing the byssus the noble pen shell attaches itself to the bottom; sometimes anchored to rocks, occasionally interwoven with seagrass but most commonly standing erect in the sand. The noble pen shell is endemic to the Mediterranean Sea, meaning that you will find it nowhere else on the planet. The shell can be found anywhere between 1 meter and 60 meters depth.

Sea silk

The byssus can reach lengths of roughly 20 centimeters and are less than a tenth of a millimeter thick. The fabrication of sea silk starts with divers carefully removing a portion of the byssus from the base of the noble pen shell underwater. Providing the byssus is ‘harvested’ with care and in moderate amounts the pen shell will continue to live and produce new threads. The harvest is followed by a process of washing and drying, soaking in lemon juice, again washing and finally the spinning of the thread. This treatment results in a golden ‘glow’ of the thread that never fades. The whole procedure is both labor intensive and time-consuming. The production of 250 grams of sea silk requires the byssus of approximately 1000 noble pen shells. It should therefore come as no surprise that garments or fabrics made with sea silk are extremely valuable.

Historical records suggest that ancient Egyptians were among the first people to fabricate and use sea silk. Supposedly only the royal family of the pharaoh was allowed to wear garments made with sea silk. It is said that Pharaoh Tutankhamun (more commonly referred to as King Tut) only wore garments made with sea silk.

Throughout the centuries the precious sea silk was predominantly worn by people of royal or wealthy descent. There is also evidence of sea silk having been used to produce the cloaks of Roman centurions. There are even accounts suggesting that the golden fleece that Jason and the Argonauts were seeking was in fact sea silk. Various scholars, however, have refuted this hypothesis.

Samples of garments made with sea silk are on display in museums around the globe. Today only a handful of women remain, all from the Italian island of Sant'Antioco near Sardinia, reverently practicing and carefully protecting the art of sea silk fabrication and weaving.

Over the years the number of noble pen shells has rapidly shrunk due to over-fishing, destruction by trawling and anchoring, the decline of sea grass fields and pollution. Already for some time now the noble pen shell has been listed as an endangered species in the Mediterranean Sea, prohibiting by law the deliberate capture or killing of the shells. But the ban is often poorly enforced, with the noble pen shell population continuing to shrink. It is not unusual for divers or snorkelers to remove the shell from the bottom to take home as a souvenir. The last two years has seen the rise of a new enemy as mass mortality events are occurring throughout the Mediterranean.

Our next Blog will shed more light on what in the meantime is starting to look as the doomed fate of the beautiful noble pen shell.