Sponges can be longer than 5 m.
The shape, size and colour of a sponge vary widely. They can be tubular, round, tree-shaped, long, and wall-like or shaped like a cup. All sponges have a wall with small and larger gaps. They vary in colour from orange to red, black, beige and brown.
Sponges belong to the Porifera phylum which comprises of more than 15 000 species. They consist of collagen, lime, silica spicule or sponge which maintain the shape of the sponge. Small hairs named flagellae move around in the water around the sponge which aids their feeding. A sponge can regenerate from a tiny piece, and they reproduce by planktonic larvae and budding.
Sponges feed on small particles, but some are carnivores that feed on crustaceans that are less than 1mm in size.
They can be found in all temperate and tropical oceans across the world.
Cup sponge - Ircinia sp.
Greek sponge - Spongia sp.
Wall sponge - Spirastrella sp.
© Johan Boshoff