Wildlife and aquatic plants and animals can also be harmed through the consumption of contaminated fish and water. Intentional or accidental introduction of invasive species can often result in unexpected ecological, economic, and social impacts on the estuarine environment. Through predation and competition, introduced species have contributed to the loss of some native populations and the drastic reduction of others. Overpopulation of some introduced herbivorous species has resulted in overgrazing of wetland vegetation and degradation and loss of marsh habitat. Other impacts include increased erosion and interference with sport and commercial fishing and beach use.
Marine debris enters an estuary by washing in from storm sewers and with the tide.
Marine debris is one of the more widespread pollution problems threatening estuarine and coastal systems. Debris comes from many sources, including improper disposal of trash on land, storm water runoff and combined sewer overflows to rivers and streams, ships and other vessels, and offshore oil and gas platforms. Once litter gets into the estuarine environment, it seriously affects wildlife, the environment, humans, and our economy. Coastal communities lose considerable income when littered beaches must be closed or cleaned up. Through its approach of inclusive, community-based planning and action on the watershed level, the NEP is an important initiative in conserving our estuarine resources and an effective model for the protection and management of other coastal areas.