Marine artificial reefs are described as "each material or each matter that is intentionally placed in a marine area, where that structure does not occur under natural circumstances and to mimic certain characteristics of a natural reef as a main goal (Jensen, 1998; Svane & Petersen, 2001; Seaman, 2000; Anonymous, 2003). Artificial reefs can influence the infauna of the natural nearby soft-sediments in different ways: (1) by changing the hydrodynamic regime and the physical characteristics of the sediments, (2) through the modification of the distribution and/or composition of the available food sources and (3) through the change of the biological interactions between different parts of the food web. One of those factors can dominate over the others or the different factors can act together (Ambrose & Anderson, 1990; Danovaro et al., 2002). In the present study, we investigate the influence of changed predator-prey interactions versus the influence of physical changes on the infauna of the natural soft-sediments nearby artificial reefs.