Royal apparel, ladies' gloves and the Fan Mussel

The fan mussel is the largest marine bivalve in Britain, reaching up to 12" (30 cm) in length, but it has interest in ancient and modern times well beyond a matter of size. Its names reveal something of its nature. Scientifically it is known as Atrina fragilis (although for many years it was called Pinna fragilis) emphasising the fragility of the shell. The French called it a 'jambon' because it resembled a small ham, whilst the Italians called it a 'cappa lunga' (long cloak), repeated by Plymouth fishermen as 'caper longer'. Pliny described it as 'the silk-worm of the sea, and its product was known to 'the ancients' as Pinna silk , Pinna wool and fish wool.

This species is adapted to live in fine sand or silt, with the point of the 'fan' at a depth that enables the other end of the shell valves to be just above substrate level to catch food particles. The shell is anchored by fine gold-coloured silken threads (collectively known as a byssus) spun by a special gland. The mussels (Mytilus edulis and Mytilus galloprovincialis), that cluster thickly on rocks around our shores, also moor themselves by byssal threads but these are coarse and wiry, suitable for attachment to a hard surfaces. The byssal threads of the fan mussel are so fine that they can be fixed to individual sand grains. This mussel is always gregarious so the combined strength of the interlacing mooring strands makes a single specimen difficult to detach; indeed one is more likely to break the shells with a grapple than pull it away from the sea bed.

Although Atrina species were once served as cutlets or made into soup by wealthier people in Mediterranean countries, it was prized above all for its gold-coloured 'silk'. This is very durable and does not lose its colour. It has been used in the manufacture of costly apparel used by royalty and it has been suggested that Henry VIII wore such a vestment during a famous battle in the 16th century rather than one of spun gold and silk, hence the site known as the Field of the Cloth of Gold.

In more plebeian circumstances, a muff 'made in Cornwall' was shown in the 1851 Great Exhibition, and in the British Museum there is a pair of gloves knitted from this thread. Knowing that I was very keen to see a sample of this rare craft, my husband asked an Italian student if she could help, as we knew that in the 19th century the nuns of Tarentino had kept the skill alive by producing small examples. Once she was convinced that 'Pinna silk' really existed, she set about the task with commitment and sent a sample of the byssi combed and sewn on to a cloth base probably from the Mediterranean Atrina nobilis. Before being used in a combed or knitted form, the bysssi need washing, drying and combing, before either being sewn in tufts or spun.

Atrina fragilis has a southern distribution, reaching its northern limit on the British west coast, being found especially in the far south-west. However, it has never been common and is now positively very scarce. It is hard to believe that in the 1840s Jonathan Couch recorded it as 'in multitudes' off the Dodman (then called the Deadman). In the 1880s the Rev. R. W. J. Smart, Tresco Chaplain, who studied the local mollusc fauna, found it sparingly in the eel-grass beds at low water. In an undated collection (probably made over several years at the turn of the 19/20th century) by Miss Jenkinson, I saw a few dozen fine shells complete with their byssi. A few years ago, a fine large specimen was found in the mouth of the Helford River.

Atrina fragilis is currently the subject of one of Natural England's Biodiversity Action Plans. Perhaps warmer seas will increase spat fall, or its recovery might be helped by appropriate No Take Zones as it is particularly vulnerable to dredging with its brittle valves protruding just above the surface of the substrate.

Stella Turk

Editor PET: I understand that the very supple material is still produced in Italy not only for gloves but cloths for polishing delicate jewellery and a range of small articles for the tourist trade. In the film "The Ten Commandments" Moses says "this golden gown was spun from the beards of shellfish"……….!

Extract from HVMCA newsletter No.30 Spring 2005