The empirical evidence for the social-ecological impacts of seaweed farming

Seaweed farming is widely expected to transform the way we approach sustainable developments, particularly in the context of the ‘Blue Economy’. However, many claims of the social and ecological benefits from seaweed farming have limited or contextually weak empirical grounding. Here we systematically review relevant publications across four languages to form a comprehensive picture of observed—rather than theorised—social and environmental impacts of seaweed farming globally. We show that, while some impacts such as improved water quality and coastal livelihoods are consistently reported, other promulgated benefits vary across cultivation contexts or are empirically unsubstantiated. For some communities, increasing dependence on seaweed farming may improve or worsen the cultural fabric and their vulnerability to economic and environmental shocks. The empirical evidence for the impacts of seaweed farming is also restricted geographically, mainly to East Asia and South-East Asia, and taxonomically. Seaweed farming holds strong potential to contribute to sustainability objectives, but the social and ecological risks associated with scaling up global production remain only superficially understood. These risks require greater attention to ensure just, equitable, and sustainable seaweed industries can be realised.