Frequently Asked Questions

Q. What is ballast water?

A. Ballast water is a certain amount of water that ships take in for stability and trim before a voyage. Once the ship arrives at its destination it may release this ballast water into the destination harbor. Ballast is primarily composed of water, and is full of stones, sediment, and thousands of living species; hence, foreign ballast water is the main avenue for the introduction of exotic aquatic species into indigenous waters.

Q. How much foreign ballast water is dumped in the United States?

A. Estimates are that ships pump more than 21 billion tons of ballast water into U.S. waters every year; that is, 40,000 gallons a minute or nearly 700 gallons a second. One ship alone can carry up to 10 million gallons of ballast water.

Q. What types of organisms are carried in ballast water?

A. Over 3,000 marine species travel around the world in ships’ ballast water on a daily basis. They range from microscopic bacteria to large fish and plants.

Q. Are any foreign ballast water species dangerous to human health?

A. Yes. Recent testing of ballast water revealed that many contained large volumes of harmful viruses and bacteria. Of particular concern is the bacteria that causes cholera, a deadly disease. Scientists believe that cholera is being spread rapidly around the world via ballast water.

Q. How do ballast water foreign species affect the economy?

A. One study estimates that the total costs of invasive species in the United States amount to more than $100 billion each year. For example, the zebra mussel invasion has caused billions of dollars in damages by clogging the water systems of cities, factories, and power plants. Similarly, the invasive sea lamprey has decimated trout and other fish stocks in the Great Lakes, resulting in $13 million a year being spent by Canada and the U.S. in an attempt to control this pest.

Q. How do ballast water foreign species affect ecosystems?

A. When alien species enter into an ecosystem, they can disrupt the natural balance, reduce biodiversity, degrade habitats, alter native genetic diversity, transmit exotic diseases to native species, and further jeopardize endangered plants and animals. In addition, when there are no established natural controls, such as predators to keep the non-native, harmful species in check, there can be a population explosion of the invasive non-native species, causing an ecological catastrophe.

Q. Do ballast water foreign species increase the threat of endangered species?

A. Yes. Some 20 percent of all freshwater fish species are at risk of becoming extinct in the near future because of invasive species. Also, invasive species impact nearly half of the species currently listed as threatened or endangered under the U.S. Endangered Species Act.

Q. How can organisms survive long journeys inside the bowels of a ship?

A. A modern cargo ship can carry up to 10 million gallons of ballast water. Given that most ships dump their ballast water every two or three weeks, this much water gives traveling organisms an ample amount of oxygen and other nutrients to survive. In addition, when faced with unfavorable conditions, some microorganisms and plankton species will form spores or other tough outer coverings for protection. As a spore, an organism may survive for a long time without food or in a different salinity or temperature than its natural environment. Once the environment becomes favorable again, such as when they are discharged into a port, the organism may change back to its active form.

Q. Ships have been traveling the world for hundreds of years, why is there a problem now?

A. It is true that exotic species have successfully invaded foreign waters over the years. However, with the advent of “free trade,” the advanced speed of modern ships, and the enlarged volume of ballast water, the number of successful invasions is rapidly increasing. In addition, prior to the early 1970’s ballast water was less of a concern because many of our harbors were so polluted that neither native species nor alien species could survive in them.

Q. What is “Open-Sea Exchange?”

A. Ballast water exchange involves replacing coastal water with open-ocean water during a voyage. This process reduces the density of coastal organisms in ballast tanks that may be able to invade a recipient port, replacing them with oceanic organisms with a lower probability of survival in near-shore waters.

Q. Why isn’t it wrong to dump ballast water in the open sea?

A. Most foreign species stowed away in ballast tanks die when released into the nutrient-poor, salty open sea. The species that do survive will not have an ecological impact because the open sea has already been exposed to them.

Q. Can you detect if a ship did not exchange ballast water in the open sea?

A. Yes. The U.S. Coast Guard tests ballast water for a minimum salinity level of at least 30 parts per thousand. If it is below 30 parts per thousand, the ballast water was, most likely, not exchanged in the open sea.

Q. What can I do?

A. Each individual plays an important role in slowing the introduction and spread of unwanted non-native species. While we cannot eliminate unwanted introductions, we can minimize them. Here are some suggestions on how you can help:

• Teach your children about the richness of ecosystems. Explain that plants, animals, and microbes all live as part of a larger system – one cannot be affected without impacting another.
• Participate in community groups designed to restore habitat or to survey, remove, and report sightings of invasive species.
• Never release unwanted pets or try to establish a favorite fish, shellfish, or plant species in a new body of water.
• Always remove any aquatic weeds, mollusks, or other accidental hitchhikers on your boat, diving gear, jet skis, trailers, floatplanes, or other equipment before leaving an area. Drain water from your boat and any other areas that hold water.
• Empty bait buckets on land or into the trash.