In recent years, many people have become increasingly aware that the globalization of trade, the increased speed of travel, the massive volume of cargo shipments, and rising tourism have combined to increase the chance of accidental introductions of foreign species into the United States. Aquatic species arrive through a variety of mechanisms -- unintentionally when attached to vessel hulls or carried in vessel ballast water and intentionally when imported for aquaria display, as live seafood for human consumption, or as a transplant to increase sport fishing opportunities. The arrival of zebra mussels in the Great Lakes and their subsequent damage to city water supplies and electric utilities has focused significant attention on ballast water discharge by cargo ships as a high-risk mechanism for species invasion. New management efforts attempt to address this concern. Congress is considering legislative proposals to amend and reauthorize the Nonindigenous Aquatic Nuisance Prevention and Control Act, including specific provisions that would modify how ballast water is managed. This report provides background on various approaches to ballast water management and reviews current ballast water management laws and programs. This report will be updated as this issue evolves.

Cover title. "April 8, 2004." Includes bibliographical references.