Reinventing anti-fouling paint to support marine biodiversity

Controlling biofouling—the unwanted accumulation of marine organisms on ship hulls—poses a major challenge for the maritime sector, as this biofouling increases fuel consumption and contributes to the spread of invasive species. As Karine Lemarchand, a professor at UQAR at the time of the study, explains, current solutions are problematic: more than 95% of ships use paints containing biocides that are toxic to local flora and fauna. Faced with increasingly strict regulations, particularly in Europe, where many chemical agents are now banned, it has become imperative to develop other sustainable solutions. The challenge is therefore to maintain the efficiency of maritime transport while halting the contamination of marine ecosystems and safeguarding the health of workers who handle these protective paints.

The PAINTS project brought together researchers from Québec and France to test eight innovative coatings based on xerogels and silicones. Karine Lemarchand points out that, unlike traditional methods that kill organisms, these technologies rely on mechanical properties that prevent strong adhesion: the simple movement of the ship is often enough to dislodge the microbial biofilm, an essential step in biofouling. Tests were conducted under varied conditions, from Rimouski and Sept-Îles to Toulon, Lorient, and Réunion Island. This multidisciplinary approach confirmed that certain biocide-free coatings, although slightly less effective than their toxic counterparts, offer real efficacy while remaining safe for the environment.
Although promising, these new coatings are not yet fully ready for large-scale commercialization. Future research will need to focus on improving the durability of these products and on better understanding their potential to combat colonization by pathogenic species. The project also revealed sociological barriers: a survey of boaters shows that while there is openness to change, higher costs and concerns about reduced effectiveness are hindering the adoption of these products. The transition to fully eco-friendly boating will require support from public authorities to encourage these innovative solutions.

References

• Portas, A., Quillien, N., Culioli, G., & Briand, J.-F. (2022). Eukaryotic diversity of marine biofouling from coastal to offshore areas. Frontiers in Marine Science, 9, 971939. https://doi.org/10.3389/fmars.2022.971939
• Hao, R., Li, T., Zhou, X., & al. (2026). Strategies and challenges in marine antifouling coatings: Current innovations and future outlook. Journal of Coatings Technology and Research, 23, 77-101. https://doi.org/10.1007/s11998-025-01123-6
• Qian, P. Y., Cheng, A., Wang, R., & al. (2022). Marine biofilms: Diversity, interactions and biofouling. Nature Reviews Microbiology, 20, 671-684. https://doi.org/10.1038/s41579-022-00744-7
• Zang, X., Ni, Y., Wang, Q., Cheng, Y., Huang, J., Cao, X., Carmalt, C. J., Lai, Y., Kim, D. H., Liu, Y., & Lin, Z. (2024). Non-toxic evolution: Advances in multifunctional antifouling coatings. Materials Today, 75, 210-243. https://doi.org/10.1016/j.mattod.2024.03.018