Effects of the dam After building the Brouwersdam there was no water flow in the Grevelingen for there were no tidal movements. This was a problem for many birds who are used to find their food at low tide on the banks. Because their habitat changed many shellfish and plants which are used to be flooded on a regular base died within several days. Two weeks after closing the Grevelinge the shores were an immense grave yard. First life in the water was no problem. But because the water was not refreshed there came a lack of oxygen. Also food and micro-organism for shell fish from the North Sea diminished. Many animals and plants died and started to decay. For this process oxygen was needed. The extinction was accelerated. But nature is strong and many species adapted and survived. For the lack of tidal movements the shores dried out and were damaged. To stop the erosion of the shores grasses and other plants were sowed. Also wooden fences and other obstructions were placed for the sand stop to be blown away an to start creating dunes. This new profiled landscape was adopted by many other than the original bird species. Also in the water many new species are found. Many people were afraid that the closing of the Gevelingen would be the end of the world’s famous Zeeuwse oysters. Because most of the oysters already died in the winter of 1962-1963 they thought this dam would be the end of this industry... But one day they discover oysters in the Grevelingen. They have survived and are still reproducing. The future of the oyster industry was ensured.