The structure of a decapod crustacean community on a littoral detritic bottom (coarse sand, fine gravel, Amphioxus sand, and abundant bioclastic remains) of Southern Spain (Barbate Bay, near the Straits of Gibraltar), at 15–24-m depth, from October 1993 to August 1995, has shown annual changes. These changes could be due to natural factors (river flow as consequence of differences in pluviometry between years) and anthropogenic disturbances happening in front of the sampling area during a second period (namely the dredging and enlargement of the harbour and the restoration of a beach), which affected directly or indirectly (through the movement of particulate matter) the structure of decapod community. As a result, there was a decrease in the total abundance and in the number of specimens of the dominant species (mainly Diogenes pugilator and Galathea intermedia) some of them associated with seaweed (G. intermedia and Pisidia longicornis), a reduction of the seasonality, and fluctuations in the values of the richness and diversity indices. However, before and during the disturbances, the dominant species remained the same, with only slight modification in the dominance order. In addition, the accumulative total annual values of the diversity indices are very similar. All these results could mean the existence of higher resistance to disturbances (none strong) in the decapod community from hydrodynamic areas. On the other hand, the strong currents increase the dispersion of the sediments, reduce the turbidity, and facilitate a more rapid return to the previous conditions, increasing the elasticity of the system, in which the decapod community presents a cyclic structure.