Almost 40 percent of the world's population lives within 100 km of a coastline, an area that accounts for only about 20 percent of the land mass. Population increase and conversion for development, agriculture, and aquaculture are reducing mangroves, coastal wetlands, seagrass areas, and coral reefs at an alarming rate. Fish and shellfish provide about a sixth of the animal protein consumed by people worldwide. A billion people, mostly in developing countries, depend on fish for their prime source of protein. Coastal ecosystems have already lost much of their capacity to produce fish because of overfishing, destructive trawling techniques, and destruction of nursery habitats. Rising pollution levels are associated with increasing use of synthetic chemicals and fertilizers.