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Sponge harvesting and processing

History of sponge harvesting and processing

In the late 17th century, the Franciscian Antun who came from Crete showed the people of Krapanj how to harvest and clean sponges. They first harvested the sponges with the gaffe from a boat at a depth up to 16 m. In the middle of the 19th century, they had around 40 sponge boats, and in 1893 they introduced the first diving appliance – a soft diving suit or heavy diving equipment.

The Trieste fishing association, which was supported by the Naval Government in Trieste, acquired the appliance and handed it over to the businessman Josip Jurić. This promoted the sponge harvesting and processing into a very lucrative economic branch. In 1911, the people of Krapanj involved in sponge business founded a sponge cooperative with 16 divers, 6 diving appliances and 30 boats. After World War I, they received financial assistance from the Maritime Administration for the revitalization of sponge harvesting and processing, and in 1930, a small workshop for sponge processing began its operation in Krapanj.

In 1947, the company Spužvar was founded and in 1953, a large sponge refinery was opened. In 1956, the company Spužvar and the fishermen cooperatives from Zlarin, Žirje and Jezera went with 30 divers and 14 boats to harvest sponges along the coast of Egypt and Libya.

The Krapanj sponge harvesters, along with sponge harvesting, developed their skills of excellent divers, they worked on rescuing of sinking ships and on the construction and repair of ports and submarine
installations.

About the sponge

The sponge is the simplest multicellular organism which lives in colonies from the lowest depths to depths of several hundred meters. Apart from several variants of sponges that have their useful value, there are many other types of sponges living in the sea. Only one kind lives in fresh water.

The useful kind of sponge is pretty sensitive and requires certain living conditions. It needs warm, salty, calm and fairly clean sea. The best quality pieces can be found at depths of 15 to 45 meters. Sponges are filters of seawater. With their tireless filtration they clean the sea from the semi-polluted remains of dead organisms which serve as their food. They are reproducing sexually, through fertilizing of eggs with sperm, followed by developing of larvae that float in the sea for a while, until they attach to the hard bottom, and asexually-vegetatively when they bud into a colony.

A brown skeleton remains after cleaning and removing of all the soft parts. It is made of fine and elastic spongin fibres, similar to horn fibres in their composition. Spongin has up to 14% iodine in its composition. A gram of dry sponge skeleton contains as much iodine as 130 litres of sea water.

Diving

The people from Krapanj involved in harvesting and processing of sponges also went through various crises due to the limitations of harvesting grounds, especially at the time when sponge harvesting was done with diving equipment and motor-powered boats. The best sponge can only be found on the hard shore bottom in some areas. Motorized boats and diving equipment quickly exhausted the available stock, so sponge harvesters were now forced to search in greater depths.

Diving with heavy equipment was safer, and the team consisted of two divers and several assistants. The divers went to the sea alternately due to the low pressure compressors (12 atm, 300 litres) that they had on boats. Once a day divers went to depths of more than 40 meters. From then on, the people of Krapanj have developed sponge harvesting and processing and diving to perfection.

Sponge harvesters from Krapanj are among the rare divers who end up in the hyperbaric chamber and they intensively stay from 3 to 8 hours in the sea each day, doing very hard physical work. They can also perform up to 5 consecutive dives a day at a great depth without compromising their life.

Experience, physical fitness and great courage of Krapanj divers are the reasons for being among the first diving teams in the Ship Rescue and Towing Company (later “Brodospas”), for ships that ended up at the bottom of the sea during World War II.

Frederik Tanfara is a well-known diver from Krapanj who went down at a depth of 104 m in the last century – in a regular diving suit by breath-hold diving. There were several newspapers reports about this around he world. Today, old diving equipment can be seen in the small museum of the island hotel.

Sponge harvesting

This is the basic part of a job that must ensure a certain amount and quality of the sponge. Sponges are collected in a mesh bag carried by the diver, then they are placed on the deck of the boat and exposed to the sun. At the end of the day, the sponges are returned in the same mesh bags and stamped. During the night, they are rinsed in sea suspended on the side of the boat. The sponge must be completely free from the soft parts and the outer part. In the morning, sponges are pressed into a sack made of jute where they are kept until the return to the base.

Sponge harvesting usually lasts about six months, from April to October. First departures to the sea are used for training and testing of equipment, i.e. eliminating shortcomings. One harvesting month lasts 20 days, and the remaining 10 days of the month are used for drying and the first standardized sponge sorting as well as for team rest. The sponge harvesting can take place in the natural habitats or in the sponge plantations.

Sponge processing

Sponge processing is complex work, whose quality is primarily conditioned by the first treatment of the sponge, which is cleaning after the harvesting. If this work is performed inappropriately then the further course of processing will be difficult with a bad quality and damage. Upon arrival of the harvesting team, the first “rough” sorting is performed to see the value of a certain amount. Then the sponges are sorted by size and structure, i.e. softness, to determine the proper course of processing. Then they are cleaned of larger limestone clusters, of small snails and shells, they are “cut” and then placed directly in the processing, which consists of soaking and rinsing in a few mild solutions and large amounts of water. In addition to knowing the formula, it is necessary to have a large experience and a feeling for the sponge. After processing, sponges are re-sorted, dried and prepared for confectioning. The market usually looks for fine and completely processed sponge, with a gentle yellow colour, without limestone deposits and dust, and with the completely neutralized effect of all the solutions it was exposed to. For certain purposes, it is enough to go through a part of the process.