Résumé : Biofouling is one of the most challenging problems for the maritime industry that has been minimized through the application of coatings containing anti-fouling (AF) biocides (e.g. Cu-based compounds; DCOIT) in immersed structures. An innovative eco-friendly approach based on the encapsulation of AF biocides in engineered nanomaterials (e.g. silica mesoporous nanocapsules (SiNC)) has recently been applied to control the leaching rate and the environmental impacts of AF biocides when used as additives in coatings. Thus, the present study aims to: (a) assess the toxicity towards marine species of three innovative AF nanomaterials: SiNC loaded with DCOIT (SiNC-DCOIT); SiNC coated with silver (SiNC-Ag); SiNC loaded with DCOIT and coated with silver (SiNC-DCOIT-Ag)) and free counterparts (DCOIT, ionic silver and empty SiNC) and (b) test if encapsulation reduces the toxicity of biocides to non-target species maintaining the anti-fouling efficacy against target species. To achieve this goal, eleven marine species (three target and eight non-target) were exposed to the test compounds, following standard protocols, with adaptations for some species. DCOIT and silver were found to be very to extremely toxic to the target and non-target species tested. Encapsulated biocides reduced their toxicity for non-target species while showing a good AF performance towards fouler species. The present study demonstrated that the encapsulation of DCOIT and silver into silica nanocapsules is a promising efficient and more environmentally-friendly anti-fouling solution comparatively to free commercial biocides.