Long Island Sound is an estuary, a place where salt water from the ocean mixes with fresh water from rivers draining from the land. Like other estuaries, Long Island Sound abounds in fish, shellfish, and waterfowl. It provides feeding, breeding, nesting, and nursery areas for diverse animal and plant life. Long Island Sound also supports many recreational and commercial uses. More than 8 million people live in the Long Island Sound watershed and millions more flock yearly to the Sound for recreation. More than $5 billion is generated annually in the regional economy from boating, commercial and sport fishing, swimming, and beachgoing. The ability of the Sound to support these uses is dependent on the quality of its waters, living resources, and habitats. Sound Health 2001 highlights water quality conditions, the status of living resources that call the Sound home, trends in land use and development, and other indicators of environmental health. By providing a snapshot of current conditions and trends, Sound Health 2001 helps to assess the effectiveness of efforts to deal with issues such as nitrogen pollution, sediment contamination, habitat restoration, and the health and abundance of living resources.