There are even some freshwater species, too.Ībout 34 species of sponge thrive off of Canada’s Atlantic coast. They grow in all marine climates, from tropical to polar waters, and survive in all latitudes – from intertidal to the deepest regions of the sea. Sponges range in size from less than 3 cm to around 2 m (6 feet) in length. So today, most household sponges are made of synthetic materials. At one point, however, those sponges were overharvested. A small percentage of sponges are harvested for commercial use (think loofahs). Scientists have identified around 8,500 species, but more than 25,000 are believed to exist in the ocean. They grow in all different shapes, sizes, colours and textures. Sea sponges are one of the world’s simplest multi-cellular living organisms.

They have no central nervous system, digestive system or circulatory system – and no organs! But they grow, reproduce and survive much as plants do. Yes, sea sponges are considered animals not plants. Photo credit: Coral & Sponge Conservation Strategy for Eastern Canada 2015

How does sponges move?