Introduced species are a growing and imminent threat to living marine resources in the United States. Hundreds of species arrive in U.S. waters from overseas each day, playing a game of ecological roulette with ecosystem and economic stability. These species arrive by way of ships' ballast water and hull fouling, by fisheries activities, and by other means. Hundreds of introductions have occurred and non-native species now inhabit many coastal marine communities from the Hawaiian Islands to New England. Every assessment indicates that the rate of marine introductions in U.S. waters has increased exponentially over the past 200 years and there are no signs that these introductions are leveling off. New introductions are occurring regularly on all coasts, producing immediate and damaging impacts, and leading to millions of dollars in expenditures for research, control, and management efforts. In San Francisco Bay alone, for example, an average of one new introduction was established every 14 weeks between 1961 and 1995.
Prevention is the most important step in the management of introductions. For most vectors, no formal legal or regulatory management tools are in place to prevent or reduce introductions, or to control newly discovered introductions. With coastal ecosystems threatened by a broad array of human impacts, U.S. marine environments may be increasingly susceptible to introductions of nonindigenous species. There is a need for national compulsory ballast and fouling management programs, an intentional introductions management program, a national rapid-response and early-warning invasions system, a vastly expanded bioinvasions research program with regional marine bioinvasion monitoring surveys, and a greatly expanded education and public awareness campaign.