Sea sponges are very simple multicellular animals. They are one of the first multicellular creatures that developed on Earth. There are 5000 sponge species and their scientific name is- PORIFERA. Only 15 variants have usage values and sponge harvesters call them- tame sponges.
Tame sponges are wide-spread in all warmer seas and are renewed natural resources.
A variant of a very popular sponge of high quality is wide- spread in the submarine world of the Croatian Adriatic. It is Euspongia officinalis Adriatica- Fine Dalmata, sort A, that can grow up to 40 centimeters in diameter. The most popular shape is that of a completely fine structure, full and roundish, size from 15- 21 centimeters in diameter.
Together with this sponge grows Euspongia officinalis lamella- Elephant's ear- sponge of a very specific shape and toughness which can grow over 1 meter in diameter. It is popular among rare buyers and used for special purposes. Euspongia zimoccae- Zimocca is wide- spread to a lesser degree and in shallow areas and in its quality falls back from the Fine Dalmata.
The most wide-spread sponge group that grows along the coasts of Greece, Turkey, Syria, Egypt, Libya, Tunisia, local waters of Sicily and the middle part of the Mediterranean is Hippospongia Communis- Cavala or Kapadiko. Adriatic variants also grow in that places but their quality is lower there. A sponge of a very fine structure- Euspongia officinalis mollessima- Levantin's sponge grows in a very little quantity along the coast of Syria. The area around the Mexican gulf, Florida, Kuba, the Bahami Islands is abundant in shapes of the Hippospognia group. The sponges of top quality are: Honeycomb or Sheepwool, Silky- grass, Yellow and Reef. The important growing areas of tame sponges are the Philippines but the quality of that sponge falls back from the quality of the previous ones, especially from the Mediterranean sponge.
Tame sponges are pretty sensitive and they look for warm, salty, calm and clean sea.
They grow attached to the rocky parts of the sea bottom in places up to 200 meters deep, but still sponges of top quality are usually growing in places that are 5-50 meters deep.
For a tame sponge to grow 15 centimeters in diameter (middle commercial size) a period of 2-4 years is necessary, depending on the area of growth.
Most of the sponges are hermaphrodites and they produce eggs for fertilization only after 3 years of growth.
Sponges multiply sexually by fertilization of eggs and non-sexually in vegetative way when, by pumping, they grow into a big turf or colony.
Sponge pieces can also be detached from the original turf and every detached piece grows into a new turf. This property is used in the process of cultivation.
While alive the sponge is covered with a dark membrane, which consists of a great number of small holes through which the sea circulates in the inside of the sponge. Circulation, caused by vibration of ciliates, which produce special cells, brings planktons and small sea organisms with which the sponge is fed and in that way it filtrates the sea.
During one day, a sponge approximately 20 centimeters big can filtrate up to 2000 l of seawater.
After removing the membrane and soft lively substance that extands around a finely woven sponge filaments a brown, soft and usable skeleton is left.
Spongin is a unique material in nature. It is horny organic substance- albuminoid, which contains up to 14% of iodine in itself.
The use of sea sponges as a hygienic device is mentioned long time ago. Old frescoes found in Crete show the sponge use. The Romans were making brushes from the viry sponge- Elephant's ear and were using it for lining the internal side of military armor plates. In the middle Ages sponges were used more and more in churches and in medicine (iodine).
The use of the sea sponge is widely spread even today, although the modern technology, with different sintectic materials, tries to beat sponges' uncatchable natural characteristics that are: firmness, endurance, possibility of absorption, characteristic of organic substance, absence of harmful static electricity (in the process of using it) and its chemical structure. It is used in managements of the house, for care of body and face, in art restorations, in fine pottery, porcelain, leather and wood workings, in graphic industry, in churches, laboratories and medicine.