In the period February 1989 to December 1998, the fish population on the Loano artificial reef (Ligurian Sea, Italy) was visually censused almost on a monthly basis (105 censuses). A total of 44 taxa were identified. Over the 10 years, species richness per census and the Shannon–Wiener diversity index gradually increased. The progressive evolution of the community has shown both the appearance of new species (Phycis phycis, Epinephelus marginatus, Muraena helena, Parablennius gattorugine) and the disappearance of others (Gobius cruentatus). Some species typical of hard substrata (Apogon imberbis, Scorpaena notata, Serranus cabrilla) have gradually increased in density over the 13 years since construction of the reef, indicating that stabilization of the community is a slow and long-term process. Copyright 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.