The EU has been tightening restrictions on anti-fouling biocides for thirty years, and the direction is clear. Farms buying new anti-fouling equipment today need to think about what regulators will allow five or ten years from now.
The story starts with tributyltin (TBT). Through the 1980s and 1990s, TBT-based paints were the gold standard for anti-fouling across maritime industries. They worked brilliantly — but they also caused imposex in marine snails, shell deformities in oysters, and bioaccumulated through food chains. The EU banned TBT on vessels under 25 metres in 1989 and extended the ban to all vessels by 2008, following the International Maritime Organisation’s AFS Convention. The glossary covers key regulatory terms like BPR and AFS Convention.
Copper compounds filled the gap. Copper-based anti-fouling paints remain the most widely used biocidal option in both shipping and aquaculture. But copper too is accumulating in sediments beneath fish farms and in enclosed bays with high aquaculture density. The EU Biocidal Products Regulation (BPR, Regulation 528/2012) now requires active substance approval for all biocidal products, including anti-fouling coatings used in aquaculture. Copper compounds have been approved but with conditions — and environmental quality standards for dissolved copper in marine waters are getting stricter.
Norway — the largest salmon producing country in Europe — has taken a particularly firm line. Norwegian regulations already restrict copper-treated nets in certain fjord systems, and the Norwegian Environment Agency has signalled further tightening. Scottish regulators are watching the Norwegian approach closely.
Hopkins and Forrest (Biofouling, 2008) analysed this regulatory trajectory and concluded that the aquaculture industry should anticipate a future where biocidal anti-fouling is either banned outright or so heavily regulated that non-toxic alternatives become the only practical choice.
For farms planning capital investment, the picture is clear. Silicone foul-release coatings, mechanical cleaning systems, copper alloy nets (which release far less copper than painted nets), integrated management — all cost more upfront than a tin of copper paint. But the regulatory risk of going all-in on copper keeps growing.