. These reefs are rare and there is only one place where the conditions are right for this type of reef. The western Canadian continental shelf is the only known sponge reefs. Heterochone calyx or the yellow goiter sponge is one of the species of reef building sponges. It normally grows 1.5 meters tall and 70 cm around. Its wall tends to be around 1 cm thick, and there are finger like protrusions that are 20 cm long and have a diameter of 5 cm.