Spirals in Time: The Secret Life and Curious Afterlife of Seashells (23 page)

Now she jumps to her feet and bustles to the window where she holds up the thread to show us all how it gleams a bright golden hue. She breaks the thread in two and presents one piece each to Rebecca and me.

The performance complete and the thread of sea-silk made, Chiara glides around the room showing us some of the things she creates. Individuals and organisations around the world commission her to make weavings and embroideries. A group of Nelson enthusiasts have recently been in touch asking Chiara to weave them a pair of sea-silk gloves like those of their hero. She brings out a small square of knitted sea-silk with a fine open weave and lays it in my hand; it is
delicate and dainty but I’m still not quite convinced it would fit into a walnut shell. Many of her works are for churches and cathedrals, and she shows us a splendid embroidery of Mary and baby Jesus. There are no price tags, and nothing is for sale. Such a commercial venture is quite against her ethos of working with her one great collaborator, the sea. This is an entirely voluntary endeavour, made possible only by generous donations dropped in the box by the museum’s door.

In a wooden frame is a golden embroidered lion, with a fancy tail and its front paw raised. It was made several decades ago by Chiara’s grandmother, the woman who taught her how to make sea-silk. Chiara tells us how she believes her family has made sea-silk for 30 generations (by my calculations that is somewhere between 600 and 900 years). Other people in Sant’Antioco tell me that Chiara’s grandmother, just like Efisia Murroni, learnt the skills of sea-silk spinning and weaving from Italo Diana.

A row of containers on a stone windowsill are filled with coloured liquids. Chiara picks up a purple jar and swirls it around. This is the infamous dye that is produced from several species of marine mollusc. Murex shells were dredged up from the Mediterranean in their millions and crushed to produce the rich imperial and Tyrian dyes used to colour the robes of ancient Phoenicians and Roman emperors. Chiara shows me a tuft of byssus with a subtle lilac hue. Dyeing sea-silk like this is a technique that has been passed down, so she says, through generations of sea-silk weavers in her family. If this is true then they were probably the only ones doing it: there are no records of sea-silk being tinted with these molluscan dyes, or any other pigments for that matter, besides the lemon-juice treatment.

The one thing Chiara will never reveal about her sea-silk weavings is how exactly she gets the byssus to make them. Now in her fifties, she tells me she has known for 30 years how to extract fibres without damaging living pen shells. Now the shells are protected, this has become a necessity.
The precise details of how she does this remain a carefully guarded secret. She distrusts the biologists who ask to watch and study her at work, convinced they will steal her ideas and open up a new sea-silk industry that will devastate the pen shell population.

All she will say is that there are certain times of year, and certain phases of the moon, when the seabed around Sant’Antioco becomes soft enough to gently pull the pen shells from their resting places. Helped by a local, trusted fisherman she dives down without scuba gear, so she says, and snips off 10 centimetres (four inches) of byssus from each living shell, like giving them a haircut or trimming their nails. Then she pushes each giant shell back into the mud. Is this a genuine technique, or just another part of the mythology she weaves around herself?

As a cool wave of reality ripples into Chiara’s world and mingles with her stories, it’s hard to know for sure what is actually going on. She can’t legally be taking whole pen shells, and her website states that her annual sea-silk harvest is around 600 grams (about 20 ounces). If she only trims their beards she must have to process thousands of shells every year (the full beards from 50 shells will yield only around an ounce of sea-silk). She would then have to leave them alone for long enough to recover, assuming they survived. Maybe there are enough pen shells living in the waters around Sant’Antioco to support a rotational harvest like this without impacting the population; but no one, except perhaps Chiara, really knows if this is the case.

A couple of important questions hover over Chiara’s claims of a sustainable byssus harvest. First, whether the shells do indeed survive through the harvesting process and regrow their trimmed beards. Based on what is known about the biology of pen shells and other byssus-making bivalves, there is a good chance that the shells do survive, so long as their internal byssus gland remains intact. If it does, then the pen shells would need to grow whole new byssus fibres to re-root
themselves in the seabed. With their ends cut off the fibres lose their sticky pads, but that shouldn’t be a major problem. Many bivalves grow new byssus filaments throughout their lives, replacing ones that break off. Some even use them as a way of moving over the seabed, throwing out a line, then hauling it in with retractor muscles and shuffling forwards.

Another unanswered question is how long it takes pen shells to grow new byssus beards, and re-root themselves. Until they do, the shells have to stand up on their own, wedged into the mud and sand without the stretchy anchor securing them in place. If a shell gets knocked over it has no means of righting itself and could choke on the seabed and find itself vulnerable to nibbling predators. That said, if the shells are in sheltered, calm water there is much less risk of them falling over.

Judging by other species, the rate of byssus growth could be reasonably speedy. It only takes a few minutes for a Blue Mussel to make a single new fibre, although they are much shorter than pen shell byssus. Mussels can make up to 50 fibres a day, but they will speed up or slow down production depending on various factors. Fast water currents stimulate mussels to make more fibres, although only within reason (if the water flows too fast the mussels find it impossible to get a grip). The whiff of predators like crabs and starfish is enough to trigger byssus production, presumably because this fixes them more firmly to the seabed, making them difficult to eat.

Poking mussels to simulate an exposed, wave-rattled shore is another way of motivating them to get busy making more byssus. In one study mussels were agitated at different rates of between once every 4.5 and 27 seconds for up to two weeks at a time (this was done by an automated mussel-bothering machine, not a sleepless grad student); the more the mussels were disturbed, the more fibres they made.

Being able to control the rate of byssus production is important, because the process is hard work. Making these
fibres uses up a lot of energy and protein, which is why mussels will only make as many fibres as are needed according to the prevailing conditions and risk of attack. It is possible that pen shells respond to Chiara’s trimming by ramping up byssus production, diverting energy from other parts of their body to do so. How this affects them isn’t known.

It would be easy enough to find out whether pen shells with trimmed beards do indeed re-root themselves in the seabed and how long it might take, but these aren’t research topics that anyone has yet pursued. An
ad hoc
experiment did get underway in 2012 when the
Costa Concordia
cruise ship hit a rock and sank off the coast of Italy. While the ship lay on its side at the surface like the beached carcass of a giant white whale, divers surveyed the water beneath and found a nearby seagrass meadow with a population of around 200 pen shells. They decided to move them out of harm’s way.

News coverage on the internet shows divers gathering up the shells and stacking them temporarily in plastic crates on the seabed. The plan was to put the shells back in their original location, replanting them in the seabed, once the wreck was salvaged. The outcome of this transferral will help demonstrate whether pen shells can cope with being handled. Chiara tells me how annoyed she is about all this, because she thinks it gives people the idea of pulling up pen shells and making sea-silk. She worries that if the masses blunder in and copy her, it will end in disaster for her beloved pen shells.

The only way I see these giant seashells becoming endangered because of their byssus would be if new markets or appetites arose, if sea-silk became the darling of fashionistas or the substance of some other fetish. If that ever happened then a truly sustainable byssus harvest, one that doesn’t lay waste to wild pen shells, would be an unlikely dream. The real world shows us that this sort of thing almost never happens.

Look at the vicuña, a wild relative of alpacas and llamas, which lives on high grassy plains in the Andean mountains. To stay warm, these dainty camelids grow ultra-fine wool that can be spun into a fine and expensive fabric. The Peruvian government set up a labelling system for wool taken from animals that are caught at most every two years, shorn and released unharmed. Of course it is much simpler to simply shoot a vicuña and skin it. Vicuña numbers are recovering but poaching continues, as does the black market in cheaper, uncertified wool. A similar situation would probably unfold if there was ever a market for sea-silk. Luckily so far, though, demand for sea-silk remains negligible.

Chiara is kindling a desire for sea-silk but she is also fiercely protective of its source along the shores of Sant’Antioco. In many ways, she is doing the opposite of philanthropists who came before her, who tried to stimulate the sea-silk industry and help other weavers make a living.

The rarity of sea-silk fibres and the difficulty of obtaining them is a challenge Chiara faces, but at the same time it is the key to her fame and success. She clearly needs to protect the source of these delicate fibres together with the museum and livelihood that rely on them. By retelling folktales and weaving new traditions to fit with the modern world, Chiara is getting caught in the threads of her tapestries and becoming part of the story herself, and in doing so she guarantees the spotlight stays focused on her as the self-styled saviour of a fading custom and craft.

Stepping outside into the bright sunshine I clutch my piece of sea-silk, and ancient stories waft through the museum door behind me. Suddenly it strikes me how bizarre it is to be holding a piece of thread made from fibres that oozed from a mussel. Then again, why is it any stranger than wool that grew on a sheep’s back, or silk that was spat out by a caterpillar? It reminds me of the extraordinary brocaded
cape woven from the silk of a million golden orb-weaver spiders in Madagascar, and displayed in London at the Victorian and Albert Museum in 2012.

I had seen sea-silk being made and was quite convinced that this stuff really does exist, but there remained one part of the story of sea-silk I wanted to see.

I walk down the hill to a small wharf where fishermen are unloading octopuses, amorphous handfuls of soft white glop, while others tout for business; these days there is more money to be made taking tourists on fishing trips than selling the fish they used to catch themselves. Passing the large boats, kitted out for a day of fishing and feasting, I come to a smaller wooden boat painted blue and filled with ropes, polystyrene buoys and a pair of worn oars. A small fish, perhaps a goby, stares at me from the transom, dead but only recently. The skipper helps me clamber on board and I wonder if we will both be rowing. Then a little engine hidden in the stern kicks into life and we chug across the flat lagoon to a spot just offshore. For an anchor, he pushes a wooden pole through a hole in the hull, pinning us to the shallow seabed below while I scramble over the high gunwale and into the cool water.

Paddling around, snorkel in my mouth and eyes down, I catch my first glimpse of the Noble Pen Shells, nestled in a lush garden of seagrass and seaweeds. The shells look frilly and soft on the outside, but I discover they are firm to the touch as I reach down through the shallow water and gently tap one with my fingernail. When I do, the shell twitches, pulls in its white and black-flecked mantle and slowly shuts. It closes its mouth into a puckered semi-circle facing the surface above.

Living among the pen shells are plenty of other creatures. Tiny green fish dart constantly around me. A bright red starfish is splayed out on one shell, and Peacock Worms stick their heads from thin tubes, each one unfurling a crown of feathery tentacles. I spy a bubble snail, a type of sacoglossan
sea slug, sliding across a pen shell; it carries its own fragile shell on its back, like a precious marble clenched between two folds of lime-green mantle, a precise colour match for the
Caulerpa
seaweed it lives in.

I sneak up as slowly and quietly as I can on a few pen shells and peer inside to check for hiding crustaceans. For a long time, people have known about (and often become slightly obsessed with) the tiny creatures that live inside pen shells.

Known generally as pea crabs, they are commonly depicted as sentinels, watching over the blind molluscs and alerting them when trouble or food is near. Pliny the Elder described the pea crabs as signalling to the pen shells with a gentle nip whenever a little fish wandered in; the shell slams shut and then both mollusc and crab tuck into a shared dinner. More recent studies reveal there are two crustacean species associated with pen shells – a crab called
Nepinnotheres pinnothere
and a shrimp,
Pontonia pinnophylax
– but they aren’t security guards or hunting partners; the shell interior simply provides them with a safe refuge. The crabs eat the same planktonic food as the filter-feeding shells and the shrimp scrape food particles from the surface of the molluscs’ gills and snack on their pseudofaeces.