Coasts

The U.S., including the island territories, has approximately 90,000 miles of marine tidal shoreline and an Exclusive Economic Zone (EEZ) jurisdiction of 3.36 million square nautical miles of coastal ocean. The coastal zone itself is comprised of a wide range of ecologically important, unique, and often highly productive ecosystems. Coastal environments can include coral reefs, seagrass meadows, barrier islands, maritime forests, beaches and rocky shores, tidal flats, "upwelling zone", and wetlands such as salt or freshwater marshes and mangroves.

The most highly productive coastal environments are estuaries, which are the connection between the ocean and inland freshwater systems. Hundreds of estuaries indent the US. coast where they provide critical habitat for much of the fish and shellfish production and coastal wildlife diversity of the Nation. For example, 77 percent of U.S. commercial fish landings are comprised of estuarine dependent species. It is along and within estuaries, however, that the greatest human pressures are exerted.

The Problem

• Large portions of the original coastal ecosystems of the US. have been and continue to be destroyed, altered, degraded, or reduced.
• Likewise, numerous plant and wildlife species or populations have been extirpated or are vastly reduced from historic levels.
• Shellfish and fishery closures, beach closures, waters affected by eutrophication, contaminated sediments, non- indigenous species, oil slicks, marine debris, sewage discharge, urban runoff, agricultural runoff, leaking septic systems, industrial pollution, boating waste and burgeoning development are common throughout coastal and estuarine environments.
• Although coastal wetland destruction has slowed considerably since the 1970s, an estimated 31 square miles-about one and one-half Manhattans-are being lost each year. Approximately one-half of the wetlands in the lower 48 have already been destroyed since the late 1700s.

The Causes

• Overall changes to the nation's coastal environments are less the result of any one or two major causes than a series of different human activities, many extending over long time periods, whose effects interact and accumulate.
• Coastal urbanization, residential and industrial growth, highways, agriculture and silviculture, golf courses' marinas' and a wide range of other development activities reduce and fragment natural environments and disrupt wildlife populations.
• Upstream water diversions and damming (for irrigation, hydropower, flood protection, etc.) have resulted in changes in the quantity, rate, and timing of freshwater flow and the reduction of sediment and nutrient discharge into estuaries. Overall effects can range from increased coastal erosion because of reduced sediment input to reductions in commercial fishery species because of increases in estuarine salinity. By destroying spawning grounds, dams have been a major factor in the loss of many distinct races of salmon.
• Toxic chemical pollution from, among other sources, industry, agriculture and urban run-off can cause a variety of effects, including the development of cancer, lesions, genetic and developmental deformities, behavioral abnormalities, reproductive failures, sex change and death in marine animals.
• Nutrient pollution from agriculture, sewage plants, septic tanks, automobile exhaust, and numerous other sources have resulted in losses of seagrass meadows; degradation of coral reefs; fish and invertebrate kills; and local loss of species; and have likely contributed to the apparent increase in harmful algal blooms.
• Commercial shipping continues to pose a serious hazard to endangered east coast right whales, is an important vector for the transfer of non-indigenous marine organisms and is a major cause of marine debris and oil spills. Recreational boating continues to kill the endangered manatees of Florida.
• Some fisheries continue to reduce fish and shellfish populations and damage bottom habitat.

The Context

• Approximately half the US. population lives on or near the coast, despite the fact that coastal counties account for just 11 percent of the area of the lower 48 states. The coastal population density for the contiguous U.S. is approximately 340 people per square mile, more than four times the US. average. It is estimated that, by the year 2025, three out of every four Americans will live within an hour's drive of the shoreline.

The Solutions

• There is widespread agreement among naturalists and scientists monitoring marine and estuarine environments that the effect of human activities on the Nation's coastal regions have been-and continue to be- profound. Though many factors are involved, it would appear evident that human population size and growth, overall lifestyle choices, and approaches to "development" will continue to play significant roles.
• Management programs that do not take into account these, and other, driving forces run the risk of being reactive and, ultimately, ineffectual. With this in mind, management-based solutions will necessarily require long-term planning, strong governmental leadership, and the expansion of government partnership programs with local communities and citizen groups.
• Important steps in this process include such current initiatives as the EPA's National Estuary Program or the Fish and Wildlife Service program to restore habitat through cooperative voluntary arrangements with landowners. Also, local initiatives to place caps on coastal development are beginning to show up on ballots.