Cannabinoids inhibit zebra mussel (Dreissena polymorpha) byssal attachment: a potentially green antifouling technology.

Macrofouling by zebra mussels (Dreissena polymorpha) has serious environmental, economic and legal consequences for freshwater shipping and raw water facilities. Current antifouling technologies, such as organometallics or aggressive oxidisers, have negative environmental impacts limiting their application. As part of an effort to discover antifoulants with a reduced environmental footprint, the endocannabinoid, anandamide and nine other compounds sharing structural or functional features were tested for their ability to inhibit zebra mussel byssal attachment. A byssal attachment bioassay identified six efficacious compounds; four compounds also had no negative impact on mussels at concentrations maximally inhibiting byssal attachment and three of them had no significant cumulative toxicity towards a non-target organism, Daphnia magna. This discovery demonstrates that both naturally occurring and synthetic cannabinoids can serve as non-toxic efficacious zebra mussel antifoulants. Applications with this technology may lead to a new genre of cleaner antifoulants, because the strategy is to prevent attachment rather than to poison mussels.