The “Blue Economy” is used to describe all of the economic activities related to the sea, with a special emphasis on sustainability. Traditional activities such as fisheries, but also undersea mining, tourism, and scientific research are included, as well as the phenomenal growth of aquaculture during the past decade. All of these activities, and the irresistible prospect of another new frontier, has led to enthusiastic and, most likely, overenthusiastic assessments of the possibilities to exploit the sea to feed the world, provide low-cost energy, become a new source of minerals, and...