They are sessile animals that means they are attached on a substrate on the sea bed and have a long life span.

They have important roles in various habitats. For instance, some sponge species live symbiosis with bacteria, arthropoda and echinoderms.
They form the dominant species in the benthic habitats. Whereas approximately 5000 species distribute in the world seas; 600 species live in the Mediterranean.
In our country, in the past years, sponge fishing had been conducted in Marmara, Aegean and the Mediterranean Sea. However in 1986 the sponge population decreased due to a disease. Therefore sponge fishing is prohibited in our country.