This chapter presents a positive example of marine management with nutrient management in the Baltic Sea and shows that it is essential to have effective international treaties, sound scientific analysis of the problem to find the right solution, and multi-factorial solutions. Nutrient pollution is a major threat to coastal ecosystems, and can cause algal blooms that lead to oxygen depletion or dead zones or kill coastal vegetation. Point sources of pollution in the Baltic come from municipal settlements and can be dealt with through wastewater treatment plants, but other sources include agriculture and traffic emissions of nitrogen oxides. Innovative solutions are needed to extract nutrients as well as to prevent the addition of more nutrients to the Baltic. Most of the Baltic countries are EU member states; governance of this problem is essential.