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Vol. 2, No. 2

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Ballast water a vehicle for exotic marine species invasions

Gulf of Maine "Exotic" sounds enticing in a travel brochure or on a dinner menu, but when the word refers to organisms spread from one port to another in a ship's ballast water, it means trouble.

Ballast water pumped onto a ship while it is in port contains marine species native to that area. When the water is later discharged into another port, those organisms can colonize there, affecting the ecosystem.

"Once every hour, about two million gallons [7.6 million liters] of ballast water which equals two million gallons of plankton from foreign ports is released in US coastal waters. We refer to this as marine ecological roulette," said James T. Carlton, professor of marine sciences at Williams College in Williamstown, Massachusetts. He noted that the National Research Council in 1995 ranked exotic species invasion as one of five major issues in marine ecosystems management.

Ballast water is a necessary component of shipping. "When cargo is unloaded, the ship floats high like a cork. You put 15 to 35 thousand tons [13 to 32 thousand metric tons] of ballast water into it, depending on the size of the ship, to weight the ship to counteract the buoyancy, which gives the ship better stability and maneuverability," explained Kevin Collard, Director of Operations, Environment and Safety for Marbulk Shipping, an international shipping company based in Salem, Massachusetts.

But in an effort to prevent invasions of coastal ecosystems by non-native species, shippers are being urged to exchange their ballast water in the open ocean, so that the water they discharge into their next port does not contain organisms from their last one.

"The actual process which makes exchanging ballast water at sea effective is, you replace coastal water organisms with [less adaptable] mid-ocean organisms, which are less likely to survive in coastal waters," said Lt. Larry Greene, Aquatic Nuisance Species Control Program manager for the US Coast Guard (USCG).

Invaders can devastate

Image: Ships must take on and discharge ballast water as they load and unload cargo in order to remain stable and maneuverable. To reduce the number of problematic foreign organisms brought into ports, the International Maritime Organization and US Coast Guard are urging shippers to exchange their ballast water in the open ocean."A typical ballast tank could be the size of an auditorium that seats 700 people," said Carlton. When ballast water transfer takes place in port, the discharged water can introduce what he described as a "staggering diversity of living organisms," to coastal waters, including non-native aquatic organisms and pathogens, such as cholera.

Not all of these organisms will survive in their new surroundings, but some are extremely hardy, have no natural predators in their new environment, and multiply profusely. Some invasive organisms can become toxic, posing threats to other species, aquaculture stocks, and humans. Non-native aquatic organisms can also crowd out native species by reducing the food supply or changing characteristics of the habitat.

The infamous European zebra mussel's introduction into the North American Great Lakes, and its subsequent spread to central US rivers, has jeopardized commercial and recreational fisheries, and caused expensive infrastructure problems. The mussels consume huge amounts of microscopic plants and animals, reducing available food for other species, and they have become so prolific that power plants and water delivery systems have been forced to spend millions of dollars on removing them from underwater structures and water pipes.

In the Gulf of Maine, the European green crab, European periwinkle, Japanese sputnik weed, and grey and orange sea squirts, are all non-native species. Fortunately, none have caused problems on the scale of the troubles brought by the zebra mussel. Nevertheless, cautioned Carlton, without precautions, "It's only a matter of time until we register a front-page, major invasion in the Gulf of Maine. We are not able to predict what it will mean, so we'd rather it not happen."

Mandatory compliance coming

The International Maritime Organization (IMO) in 1991 adopted voluntary guidelines for preventing marine species invasions via ballast water, and is developing mandatory guidelines that may be approved as soon as 2000, although ratification may take several years.

Meanwhile, shippers entering US ports were given three years to voluntarily comply with open ocean ballast water exchange guidelines under the US National Invasive Species Act of 1996, which is enforced by the USCG. The Act states that shippers should exchange ballast water at sea unless "that exchange threatens the safety or stability of the vessel, its crew, or its passengers." According to Green, mandatory reporting of ballast water exchange will probably begin later this year.

Greene said the USCG is developing an instrument that can differentiate between coastal and mid-ocean water that its officers will use to test ballast water on board ships. If the USCG determines at the end of the current three-year period that the voluntary compliance with the US guidelines is inadequate, mandatory requirements would likely take effect in 2001. Those requirements could be implemented on a regional or national basis, according to Bob Peoples, Executive Secretary of the Intergovernmental Aquatic Nuisance Species Task Force, established under the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990.

The Canadian Coast Guard and Fisheries and Oceans Canada are evaluating compliance with the voluntary IMO regulations in Canadian Ports. Canada has no national regulations in place, and none that cover the maritime region, according to James Lawson, Senior Regional Pollution Prevention Officer for Transport Canada.

But if IMO's guidelines become mandatory, Canada's federal government will likely issue enforceable guidelines for all of its ports that are similar to those in place on the Great Lakes and in Vancouver, requiring ships to exchange their ballast water outside of those waters, said Captain Peter Turner, Harbor Master for the Saint John Port Corporation in New Brunswick. He noted that ballast water from ships docking at the Irving terminal there is treated on shore, then discharged.

Greene said the US and Canada have coordinated closely on ballast water regulations for the Great Lakes, and would likely do so for the Gulf of Maine, noting, "It's in the interest of both nations to prevent invasions."

But while Greene described the spread of invasive species as "a global environmental problem," he said, "Our biggest concern right now is the safety of life at sea and whether vessels can safely conduct what we're asking them to do."

According to Collard, "Ships' captains must always consider prevailing navigation and sea conditions, structural safety of the vessel, and resulting stress on the ship's hull from ballast exchange." But he stated that Marbulk complies with all ballast water guidelines, whether voluntary or mandatory. "We're a service-based industry. We can't go polluting places and upsetting the ecosystem. In areas of the globe where standards are lower, we still maintain North American standards," he said.

Some wonder whether ballast water restrictions make ports more or less attractive to shippers. Ron Huber of the Rockland, Maine-based Coastal Waters Project said the Maine legislature considered a bill in 1997 directing the state to join the National Aquatic Nuisance Species Task Force, created by the 1990 Act. Lawmakers, however, worried that implementing more stringent ballast water restrictions in Maine ports might make them "less desirable to shipping."

But Sean Brilliant, Executive Director of Atlantic Coastal Action Program-Saint John, said his group worries that as international quality standards become more rigorous, New Brunswick ports without stringent ballast water plans could be considered less desirable destinations. The group plans to begin sampling the quality of ballast and bilge water entering and leaving Saint John harbor.

Researchers explore remedies

Image: Plankton sampling can reveal the kinds of organisms ballast water contains. Researchers are exploring ways to treat ballast water before it is discharged   including filtration, heat, and irradiation   to kill exotic organisms that could invade coastal areas.Research organizations are exploring ways shippers can address ballast water issues. Allegra Cangelosi, Senior Policy Analyst and co-principal investigator with the Great Lakes Ballast Technology Demonstration Project, is testing the effectiveness of filtering organisms from ballast water.

Open-ocean ballast water exchange is simply not feasible in all cases due to weather conditions, routing, or a ship's structure, Cangelosi said. "We are in desperate need of more broadly applicable approaches," she said, adding that her organization is "looking for technologies that can be used anywhere on the globe," including the Gulf of Maine.

Battelle Memorial Institute, a not-for-profit international organization, is also researching ways of treating ballast water as it is pumped onto a vessel to kill the organisms in the water, including ultrasonic treatment, irradiation, and heating the water, said Deborah Tanis, a research scientist based in Battelle's Duxbury, Massachusetts office.

Treating ballast water chemically may also be an option, but Carlton said, "We want to be conservative with biocides and cautious about diverting more chemicals into the system unless they have a very short half-life and are biodegradable."

Though open-ocean exchanges are currently the accepted method for handling potentially contaminated ballast water, both Tanis and Cangelosi agree that other options are needed. Said Tanis, "We need methods that are more effective than ballast water exchange and more feasible for shippers. We're studying the actual biological effectiveness of exchanges. It certainly will help, but I don't know that it's 100 percent foolproof. There's a need to bridge the gap between science and industry, and that means we need to come to some determination that benefits both."

MIT Sea Grant, in association with other organizations, is sponsoring a January 1999 Marine Bio-invasion Conference that will emphasize ballast water issues. Visit the conference web site or E-mail Judy Pederson at for more information.

For more information on aquatic nuisance species and marine invasions, visit these web sites:

Great Lakes Commission

International Maritime Organization

Northeast-Midwest Institute

US Geological Survey