Environmental impacts from macroalgal culturing: risk assessment for Norwegian waters.
The interest in cultivation of macroalgae is increasing and the environmental conditions along the Norwegian coast should be well suited for this activity. This report describes the knowledge basis for managing aquaculture permits for macroalgae and assesses the risk for environmental impact of macroalgae cultivation at the present and expected future upscaled levels in Norwegian waters. It is recommended that the management of algal culturing is adapted to the environmental impact it represents which in important ways differs from other types of aquaculture with generally less environmental impact compared to e.g. fish farming. Still there is little knowledge of the environmental impact from algal cultural farms and in particular farms of a size that has yet to be developed and tested in Norway. Overall, dispersal of invasive species is regarded as the biggest threat for the environment. The most important knowledge gaps are dispersal of species, including invasive species, microorganisms and diseases, and genes.