In an annex to his thesis this author put forward three viewpoints related to the degree of eutrophication of Dutch coastal waters and the southern North Sea (POSTMA, 1954; fig. 1).The first of these said that the IJsselmeer, a fresh water lake created in 1930 by the enclosure of the Zuiderzee, was in a stage of increasing eutrophication. The second expressed concern on the unlimited discharge of (organic) waste into the Ems-Dollard estuary, part of the Wadden Sea estuarine system. The third stated that the nutrient supply of the Thames river was too small to exert an influence on fish production in the southern North Sea. This last statement was a reaction to a publication of KALLE (1953) which expressed the opposite opinion.