Organotin salts, used as antifouling substances have a deleterious effect on the environment particularly on molluscs and especially on the Japanese oyster Crassostrea gigas. A synthesis of the effects of tributyltin (TBT) on cultured molluscs reveals the following effects: 1) acute and chronic toxicity to the adults; 2) accumulation in the flesh 01 the adults; 3) perturbation 01 reproduction particularly fertility, mortality 01 offspring and decrease in larval growth rate; 4) decrease in the growth rate 01 juveniles and thickening 01 the shell; and 5) modification 01 the physiology al sublethal levels.