Application of the European Regional Seas Ecosystem Model (ERSEM) to assessing the eutrophication status in the OSPAR Maritime Area, with particular reference to nutrient discharges from Scottish salmonid aquaculture

Aquaculture production of salmonids in Scotland has grown over the last 15 years, exceeded 150,000 tonnes in 2001. There have been conflicting views as to the likely ecological impact of nutrient discharges from this activity. Whilst quantitative assessments of aquaculture nutrient discharges have been carried out, the debate regarding possible eutrophication impacts of these discharges has so far been largely speculative. In order to provide a quantitative basis for this discussion, a marine ecosystem model was used to simulate the consequences of a 50% reduction in aquaculture nutrient discharges, and the results are presented here.