Marine spatial planning (MSP), incorporating multiple factors for consideration in the development of offshore aquaculture, is commonly used in site selection as well as a key tool for digital environmental impact assessments (D-EIA). By accounting for cumulative impacts from multiple farms and associated linkages, MSP tools are critical to ensure the impacts of a new developments are not underestimated within the context of existing developments. We demonstrate the application of MSP as a D-EIA tool for site selection of salmon farms in the west coast of Scotland with a focus on sea lice infestation risk and management. With plans to double production by 2030, the aquaculture industry in Scotland is developing innovative solutions to optimise site selection for reduced environmental impact.
The MSP tool combines multiple layers in a GIS workbook to include sensitive habitats, alternative industry uses, base line monitoring, impact maps for sea lice, treatment toxicants and farm waste. By integrating spatial mapping, background data and model output from both existing and proposed farms into the D-EIA process, commercial operators as well as regulators can perform multi-criteria assessments as part of the site selection process (Figure 1). For example, sea lice infestation risk from regionally linked farms as well as the environmental impacts of bath treatments. The MSP tool supports a holistic, system scale assessment of environmental impacts of individual farm operations while incorporating cumulative impacts associated with multiple farms within a distinct region. This allows regulators to understand the broader impact of multiple farms, while enabling industry to visualise the site selection process using a virtual environment with quantitative measures of risk.