The marine biodiversity of the Belgian continental shelf is well-known for the infaune of soft sediments. In addition the fauna of the hard substrates (rocks and wrecks) is little or not known. The fauna of the wrecks of the continental shelf will be studied by direct observations, samples collections by scriba divers. Three wrecks located on a north-south axis will be studied and sampled using the following techniques: photographs, in situ estimate of the density of sessile organisms and harvests of samples. The samples will be preserved for identification and estimate of the biomass. A comparison of the wrecks by means of mathematical analysis of results will make possible to determine if an increase or a decrease of the biodiversity is measurable coast towards the open sea. Lastly, the communities of the wrecks at the North sea as their structures will be outlined.