Environmental impact of kelp (Saccharina latissima) aquaculture. (June 2020) - Visch, Wouter
Abstract: The aim of the study was to assess the effect of seaweed cultivation on the coastal environment. We analysed a multitude of environmental parameters using an asymmetrical before after control impact (BACI) design, comparing the seaweed farm (impact) with multiple unaffected locations (controls). The seaweed farm had a significant positive effect on benthic infauna (p < 0.05) and was found to attract 17 mobile faunal and 7 other seaweed species, indicating that the farmed crop may provide habitat to mobile faunal species. A light attenuation of approximately 40% at 5 m depth was noted at the peak of the seaweed biomass just before harvest. No changes were observed in benthic oxygen flux, dissolved nutrient concentrations, and benthic mobile fauna between farm and control sites. These results show that seaweed aquaculture has limited environmental effects, especially compared to other forms of aquaculture such as fish and bivalve farming. Highlights: The environmental impact of seaweed aquaculture was assessed comparing the farm site with multiple control locations The seaweed farm had a positive effect on benthic infauna and was found to attract pelagic mobile fauna A shading effect of approx. 40 % at 5 m depth was noted at the peak of the seaweed biomass Benthic oxygen flux, dissolved nutrient concentrations, and benthic mobile fauna did not differ between farm and controls These results may offer a basis for the development of management policy for future seaweed aquaculture