NOAA 2007-R520
Contact: Daniel Parry
NOAA News Releases 2007
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NOAA and the Smithsonian released a technical report today that finds ship captains can dramatically reduce the supply of invasive aquatic species delivered to U.S. ports, if they flush and refill ballast tanks with ocean water before arrival. The report describes the effectiveness of ballast water exchange procedures as a way to reduce aquatic invasive species discharged into U.S. waters, including the Great Lakes and Chesapeake Bay.

If ports are exposed to non-native species, these organisms may establish themselves in the new habitat, like zebra mussels and gobies in the Great Lakes, and potentially cause harm to native populations of aquatic animals and plants. An estimated 70 million metric tons—roughly 50 million gallons per day—of ballast water is discharged in U.S. water annually.

“Research and development to produce alternative ballast treatment methods and technology-based ballast treatment systems should continue to be pursued as a high priority toward the reduction of organism transfers,” said Richard Spinrad, assistant administrator for NOAA Oceanic and Atmospheric Research. “This report assesses what is currently known about ballast water exchange, and provides analysis of its likely effects.”

NOAA’s National Center for Research on Aquatic Invasive Species and Smithsonian Environmental Research Center analyzed the delivery of ballast water to the Great Lakes and Chesapeake Bay. These studies indicate reductions in the risk of invasive species introductions as a result of ballast water exchange. The analysis provides further confidence that overall, there has been a decline in the risk of invasion from ballast water in these regions. In addition, the report addresses a potential gap in the coastal ballast management protection framework whereas ships traveling less than 200 miles from the U.S. coast are not covered.

“Measurements made aboard ships during normal operations demonstrate that ballast water exchange, when properly conducted, can be highly effective, removing or killing approximately 90 percent or more of the coastal planktonic organisms from most ballast tanks,” said David Reid, senior physical scientist, NOAA National Center for Research on Aquatic Invasive Species. “Some residual coastal organisms may remain in ballast water after exchange, and also in tanks with residual water and sediments, both which may pose some invasion risk during subsequent ballast discharge.

“It is clear that ballast water exchange has significantly reduced species transfers and invasion risk associated with ships’ ballast operations,” said SERC senior scientist Gregory Ruiz. “But the expected (albeit reduced) rate of invasions for the organisms that remain after exchange is not known. This represents a gap in scientific understanding that limits effective management decisions.”

The report suggests that a standardized survey program, targeting key coastal ecosystems in the U.S., could provide the high-quality data necessary to (a) assess current invasion risk and (b) measure the performance of multiple management actions, including those of ships and other transfer mechanisms, in terms of invasion occurrence. No such program currently exists for the nation.

The report (TM-142) is available on the Web at:

National Center for Research on Aquatic Invasive Species assures NOAA-wide leadership, communication, and coordination for NOAA's research investments in support of understanding, prevention, response, and management of aquatic species invasions in the U.S. coastal ecosystems. The center’s goal is to foster, coordinate, and support development of aquatic invasive species research throughout and across NOAA.

National Oceanic and Atmospheric Administration, an agency of the U.S. Commerce Department, is celebrating 200 years of science and service to the nation. From the establishment of the Survey of the Coast in 1807 by Thomas Jefferson to the formation of the Weather Bureau and the Commission of Fish and Fisheries in the 1870s, much of America's scientific heritage is rooted in NOAA.

NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and information service delivery for transportation, and by providing environmental stewardship of our nation's coastal and marine resources. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, more than 60 countries and the European Commission to develop a global monitoring network that is as integrated as the planet it observes, predicts and protects.

On the Web:

National Oceanic and Atmospheric Administration:

Great Lakes Environmental Research Laboratory:

Oceanic and Atmospheric Research:

National Center for Research on Aquatic Invasive Species:

National Sea Grant:

Smithsonian Environmental Research Center: