Letter to editor regarding Kotta et al. 2020: Cleaning up seas using blue growth initiatives: Mussel farming for eutrophication control in the Baltic Sea

摘要

In their recent article, Kotta et al. (2020) argue that mussel farming is a viable measure to address the extensive eutrophication of the Baltic Sea and that establishing 900 km~2 of mussel farms in the Baltic proper would be a realistic way to reach the target for reduced nutrient emissions in the Helcom Baltic Sea Action Plan (BSAP). The article provides valuable data on mussel farm yields and costs for nutrient removal in the strong salinity gradient of the Baltic Sea, showing to what extent the slow growth rate in the central and inner Baltic Sea results in lower farming yield and nutrient uptake capacity compared to a more optimal farming environment. However, as shown below, we find the estimated potential for nutrient uptake at the Baltic Sea scale grossly overestimated and poorly supported by empirical data.