Each of these regions probably has between 400-600 species. These areas include Australia, Indonesia, Papua New Guinea and other parts of the Indo-Malay archipelago. However, it is well known from studies on other groups of animals that this region has the highest proportion of the world's marine biodiversity, and there is no reason to show us that this is different for sponges. In Australia there are about 1,400 species described in the scientific literature, but we estimate that there are probably at least 5,000 species living in continental and territorial waters. Based on recent work, it is estimated there are between 200-300 species in Hawaii.
Sponges are often soft bodied, many are fragile and colors are generally unstable.
Consequently, special care is taken when collecting to minimize damage to both the sponge and collector. In many species both coloration and morphology may change dramatically following collection and preservation, and identifications, even by specialists, are often greatly facilitated if there are adequate color photographs of live material. Sponge identifications are primarily based on morphology. Some of these morphological characters vary substantially between widely separated populations, or those living in different habitats, whereas other features are much more consistent between individuals. Organic and inorganic skeleton of a sponge are usually the primary characters used for identification.