Does Mussel Farming Promote Cost Savings and Equity in Reaching Nutrient Targets for the Baltic Sea?

Mussel farming has been suggested as a low-cost option for reducing nutrient content in eutrophied waters. This study examines whether mussel farming contributes to reductions in total nutrient abatement cost and increases in equity for achieving nutrient load reduction targets to the Baltic Sea under different international policy regimes (cost-effective, country targets set by the Baltic Sea Action Plan (BSAP), and nutrient-trading markets). A cost-minimizing model is used to calculate the cost savings, and the analytical results show that mussel farming is a cost-effective option only when the marginal abatement cost is lower than for other abatement measures. The numerical cost-minimizing model of the Baltic Sea indicates that the largest abatement cost reductions from introduction mussel farming, approximately 3.5 billion SEK (9.36 SEK = 1 Euro), are obtained under the cost-effective and nutrient-trading systems. Equity, as measured by abatement cost in relation to affordability in terms of gross domestic product, is improved by mussel farming under the cost-effective regime but reduced under the BSAP country targets and nutrient-trading regimes.