The growth of organisms on seven different artificial reef structures was surveyed from 2004-2006 in Hormuzgan offshore waters (Bandar Lengeh area). The organisms consisted of 12 groups the main of which included Barnacle (Megabalanus tintinnabulum), Sponges with five families and Tunicates. The highest density was observed in 2005, amounting to some 409.224g wet weight on each structure. However, a decrease was observed afterwards in the total mass of aquatics living on the structures. Some organisms such as crabs, polychaets, bivalves and fish larvae showed an increasing in size in the first year. Bivalves showed a decreasing trend in density but otherwise an increasing trend in size over time. Artificial shape of the reefs was not effective on the total density of the organisms living on the structures. Total density of live organisms on different parts of the artificial reefs (surface, middle and bottom) was not statistically significant (P>0.05). Numbers of crabs on mixed artificial reefs were higher than the other artificial reefs. This was also the same for barnacles
