Sponges are colonies of microscopic marine organisms that excrete a fibrous skeleton. The living sponges that can be seen throughout the Aegean as black, melon-sized blobs, anchored to rocks in three to ten metres of water, are mostly “wild” sponges, impossible to clean or shape with shears. Kalymnian divers seek out “tame” sponges, which are much softer, more pliable, and dwell thirty to forty metres deep.
Sponge-fishers were originally free divers; weighted with a rock, they’d collect sponges from the seabed on a single breath before being hauled back up to the surface. Starting in the late nineteenth century, however, divers were fitted with heavy, insulated suits (skáfandhro). Breathing through an air-feed line connected to compressors aboard the factory boats, they could now attain depths of up to 70m. However, this resulted in the first cases of the “bends”. When divers came up too quickly, the dissolved air in their bloodstream bubbled out of solution – with catastrophic results. Roughly half of those early pioneers would leave with the fleets in spring but fail to return in autumn. Some were buried at sea, others, it’s said, buried alive, up to their necks in hot sand, to provide slight relief from the excruciating pain of nitrogen bubbles in the joints.
By the time the malady became understood, during World War I, thousands of Kalymnians had died, with many survivors paralyzed, deaf or blind. Even though the skáfandhro was banned elsewhere as the obvious culprit, it remained in use here until after World War II. After the first decompression chambers and diving schools reached Greece, in the 1950s, the seabed was stripped with ruthless efficiency, and the sponge fleets forced to hunt further from home.
Even the “tame” sponge is unusable until processed. The smelly organic matter and external membrane is thrashed out of them, traditionally by being trodden on the boat deck, and then they’re tossed for a day or so in a vat of hot sea-water. Visitors to Póthia’s remaining handful of workshops can still watch the sponge-vats spin; in the old days, the divers simply made a “necklace” of their catch and trailed it in the sea behind the boat.
To suit modern tastes, some sponges are bleached to a pale yellow colour with nitric acid. That weakens the fibres, however, so it’s best to buy the more durable, natural-brown ones.