Adverse effects of man's activity on the marine environment are well known. Much less publicity is given to successful examples of application of scientific knowledge to reclamation of marine habitats. In the last two decades the concept of man-made reefs as an artificial substrate has been development in the USA, Japan, Taiwan and maritime countries of West Europe. This concept, known as artificial aquatic habitat technology (AAHT), has been introduced on a wide scale. A system of man-made reefs may increase the yields of fish and shellfish captured in their vicinity by 20—400 per cent. The author discusses the experiment in the Pomorska Gulf completed in June 1990, 0.3 nautical mile from the cliffs of the Wolin Island off Grodno locality.