Organotin antifouling paints have been banned for use on small vessels in most countries but are still widely employed on large ships over 25 m in length. Paints containing copper (Cu) are the most commonly used alternative to organotins. Both Cu and organotins exhibit toxicity towards many non-target marine invertebrates (Eisler, 1998; Hall & Pinkney, 1985). Busy shipping routes, marinas and harbours exist adjacent to, or within, the boundaries of signi®cant coral reef areas (eg. TheGreat Barrier Reef). Consequently, leaching of organotins and Cu or ablation of antifouling paint chips from ships' hulls may expose corals.