Foul-release coatings are generally assumed to affect fouling of surfaces via interfering with adhesion of fouling organisms. However, the potential effects of these coatings on other aspects of the biology of fouling organisms such as behaviour have not in general been explored. The effects of wax-based foul-release coatings containing silicone oil on the settlement and behaviour of cyprid larvae of the barnacle Balanus amphitrite were studied. Settlement (as measured by metamorphosis) of cyprids was strongly inhibited on all coatings but particularly on those containing silicone oil at concentrations of 5% or more. The behaviour of cyprids was also altered on coatings containing > or = 5% silicone oil, with cyprids assuming an inverted position, preventing adhesion. This effect was reversible in part; when cyprids exposed to experimental coatings for 1 d were transferred to uncoated surfaces their behaviour returned to normal, except that metamorphosis did not occur. The results indicate that model foul-release coatings containing wax and silicone oil can affect settlement and behaviour, as well as adhesion.